Bollos Christine Anne Leah Locsin, Ryosuke Kasai, Hideki Otsuka, Youichi Otomi, Koji Yamaguchi, Tomomi Matsuura, Tamaki Otani, Takanori Bandoh, Yuya Ueki, Noritake Matsuda, Satoru Takashi, Shota Azane, Yamato Kunikane, Shoichiro Takao, Shusuke Yagi, Masataka Sata, Hitoshi Ikushima and Masafumi Harada : Ventilation/Perfusion Mismatch in Pulmonary Vein Stenosis Secondary to Atrial Fibrillation Ablation, Asia Oceania Journal of Nuclear Medicine & Biology, Vol.13, No.1, 62-69, 2024.
(Summary)
We present two patients with a history of paroxysmal atrial fibrillation who developed pulmonary vein stenosis (PVS) following atrial fibrillation (AF) ablation. Case 1 involved a female patient in her 50s who was asymptomatic for pulmonary symptoms but was found to have a high degree of left superior PVS 15 months after AF ablation. This was demonstrated using contrast-enhanced computed tomography (CE-CT) and supported by findings of perfusion defects on ventilation-perfusion (V/Q) scan. Case 2 was a male patient in his 60s who developed progressive left superior PVS nine months after AF ablation, evidenced by serial CE-CT and V/Q scans. PVS is a rare but well-known complication of pulmonary vein ablation for the treatment of AF that can lead to severe complications if left untreated. V/Q scans effectively assess the functional significance of PVS by detecting abnormal blood flow segments. Although a V/Q mismatch characterized by reduced perfusion defects is more commonly used in evaluating pulmonary embolism, PVS should not be disregarded as a differential diagnosis. Few studies emphasize the utility of V/Q scans in managing PVS and highlight V/Q mismatch as a notable finding. This case report aimed to highlight their significance.
MATSUDA Noritake, Hideki Otsuka, Ryosuke Kasai, Tamaki Otani, BOLLOS CHRISTINE ANNE LEAH LOCSIN, Shota Azane, Yamato Kunikane, Youichi Otomi, UEKI Yuya, Mana Okabe, Masafumi Amano, Masanori Tamaki, Shu Wakino, Shoichiro Takao and Masafumi Harada : Quantitative evaluation of 67Gacitrate scintigraphy in the management of nephritis, Scientific Reports, Vol.14, No.16313, 16313, 2024.
(Summary)
In Ga-citrate scintigraphy (Ga-S), visual assessment is used by evaluating renal-uptake comparison with liver and spine and is simple and objective. We adopted the standardized uptake value (SUV) for Ga-citrate and proposed two quantitative indices, active nephritis volume (ANV) and total nephritis uptake (TNU). This study clarified the utility of new Ga-S-based quantitative indices in nephritis management. Before SUV measurement, the Becquerel calibration factor of Ga-citrate was obtained using a phantom experiment. Seventy patients who underwent SPECT/CT imaging were studied. SUV, ANV, and TNU were calculated using a quantitative analysis software for bone SPECT. SUV, ANV, and TNU were analyzed using the (1) threshold method (set 40%) and constant-value method for (2) vertebral SUV, and (3) vertebral SUV. ROC analysis was used to evaluate SUV, ANV, and TNU diagnostic abilities to distinguish nephritis presence and absence as well as interstitial nephritis (IN) and non-IN. The area under the curve (AUC) for nephritis presence or absence had a good value (0.80) for SUV (1), ANV (3), and TNU (3). The AUC for differentiation between IN and non-IN groups had a good value (0.80) for SUV (1). Thus, the new Ga-S-based quantitative indices were useful to evaluate nephritis and distinguish IN and non-IN.
(Keyword)
Humans / male / female / Middle Aged / Gallium Radioisotopes / Aged / Gallium / Adult / Nephritis / Citrates / ROC Curve / Aged, 80 and over / Radiopharmaceuticals / Single Photon Emission Computed Tomography Computed Tomography
Yuya Ueki, Hideki Otsuka, Tamaki Otani, Ryosuke Kasai, Youichi Otomi, Daiki Ikemitsu, Shota Azane, Yamato Kunikane, Takanori Bandoh, Noritake Matsuda, Yasuyuki Okada, Tetsuji Takayama and Masafumi Harada : Combined visual and quantitative assessment of somatostatin receptor scintigraphy for staging and restaging of neuroendocrine tumors, Japanese Journal of Radiology, Vol.42, No.5, 519-535, 2024.
(Summary)
Somatostatin receptor scintigraphy (SRS) using In-DTPA-DPhe-octreotide (pentetreotide) has become an integral part of neuroendocrine neoplasm management. The lack of precise quantification is a disadvantage of SRS. This study aimed to adapt the standardized uptake value (SUV) to SRS, establish the SUV range for physiological uptake in the liver, kidney, and spleen, and elucidate the utility of combined visual and quantitative SRS assessment for staging and restaging of neuroendocrine tumors (NETs). This study included 21 patients with NETs who underwent In-pentetreotide SRS. The SUV of physiological and pathological uptake was calculated using bone single-photon emission computed tomography (SPECT) quantitative analysis software (GI-BONE). For visual analysis, the primary and metastatic lesions were scored visually on planar and SPECT images using a five-point scale. We assessed the relationships between the SUVs of the liver, kidney, and spleen in the dual phase, and among quantitative indices, visual score, and pathological lesions classification. Sixty-three NEN lesions were evaluated. The mean ± standard deviation maximum SUVs (SUVmax) were liver: 4 h, 2.6 ± 1.0; 24 h, 2.2 ± 1.0; kidney: 4 h, 8.9 ± 1.8; 24 h, 7.0 ± 2.0; and spleen; 4 h, 11.3 ± 4.5; 24 h, 11.5 ± 7.6. Higher SUVmax was significantly associated with higher visual scores on dual-phase SPECT (4 h, p < 0.001; 24 h, p < 0.001) (4 h: scores 3 and 4, p < 0.05; scores 3 and 5: p < 0.01; scores 4 and 5: p < 0.01; 24 h: scores 3 and 4, p = 0.0748; scores 3 and 5: p < 0.01; scores 4 and 5: p < 0.01). We adapted the SUV to SRS and established the range of SUV for physiological uptake in the liver, kidney, and spleen. Combined visual and quantitative assessment is useful for imaging individual lesions in greater detail, and may serve as a new tumor marker of SRS for staging and restaging of NETs.
Leah L. Christine Anne Bolls, Yueren Zhao, Gil P. Soriano, Tetsuya Tanioka, Hideki Otsuka and Rozzano Locsin : Technologies, Physician's Caring Competency, and Patient Centered Care : A Systematic Review, The Journal of Medical Investigation : JMI, Vol.70, No.3,4, 307-316, 2023.
(Summary)
This study aimed to conduct a systematic review to clarify patient understanding, understanding of caring concepts, understanding of technology, competency to express compassion, appropriate involvement in caring, and ethical and moral attitudes and responses toward patients. This systematic review was conducted through an electronic search across PubMed, Google Scholar, MEDLINE, and Science Direct. Authors independently appraised the methodological quality of the studies using the Mixed Method Appraisal Tool. A narrative synthesis approach was used to present these findings. Nine studies met the inclusion criteria and quality appraisal guidelines. Through thematic analysis, four major themes were identified:Technology and caring competency, Technology and patient-centered care, Empathetic skills, and Caring competency. This review has shown that patients choose physicians considering their emotions and communicate well with them, empowering them to take responsibility of their own or their loved ones' healthcare. In the age of technological advancement and availability of vast sources of information, it is expected of physicians to adapt to these character priorities while maintaining their sense of humanness, not only focusing on healing modalities, but also to guide, educate, and appropriately empower their patients toward achieving their healthcare goals. J. Med. Invest. 70 : 307-316, August, 2023.
(Keyword)
Technological competency / Caring / Empathy / Patient-centered care
Tamaki Ohtani, Hitoshi Ikushima, Yoshimi Bando, Michiko Yamashita, Kenmei Kuwahara, Hideki Otsuka, Kazuya Kondo and Hirokazu Miyoshi : Early Prediction of Radiotherapeutic Effecacy in a Mouse Model of Non-Small Cell Lung Carcinoma Using 18F-FLT and 18F-FDG PET/CT, The Journal of Medical Investigation : JMI, Vol.70, No.3,4, 361-368, 2023.
(Summary)
This study investigated the usefulness of [18F]-3'-deoxy-3'-fluorothymidine (18F-FLT) and [18F]-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging for predicting the therapeutic efficacy of non-small cell lung cancer (NSCLC) irradiation at an early stage after radiation treatment. Mice were xenografted with the human lung adenocarcinoma line A549 or large cell lung cancer line FT821. Tumour uptake of 18F-FLT and 18F-FDG was imaged using PET/CT before and 1 week after irradiation. In A549 tumours, 18F-FLT uptake was significantly decreased, and 18F-FDG uptake was unchanged post-irradiation compared with pre-irradiation. In FT821 tumours, uptake of both 18F-FLT and 18F-FDG uptake was substantially decreased post-irradiation compared with pre-irradiation. In both xenografts, tumour volumes in the irradiated groups were significantly decreased compared with those in the control group. 18F-FLT is expected to contribute to individual NSCLC therapy because it accurately evaluates the decrease in tumour activity that cannot be captured by 18F-FDG. 18F-FDG may be useful for evaluating surviving cells without being affected by the inflammatory reaction at an extremely early stage, approximately 1 week after irradiation. Combined use of 18F-FLT and 18F-FDG PET/CT imaging may increase the accurate prediction of radiotherapy efficacy, which may lead to improved patient outcomes and minimally invasive personalised therapy. J. Med. Invest. 70 : 361-368, August, 2023.
Noritake Matsuda, Hideki Otsuka, Tamaki Otani, Shota Azane, Yamato Kunikane, Yoichi Otomi, Yuya Ueki, Masahiro Kubota, Masafumi Amano, Shusuke Yagi, Masataka Sata and Masafumi Harada : New quantitative indices of cardiac amyloidosis with 99mTc-pyrophosphate scintigraphy, Japanese Journal of Radiology, Vol.41, No.4, 428-436, 2023.
(Summary)
Amyloid light chain (AL) and transthyretin (ATTR) are the major subtypes of cardiac amyloidosis (CA). Tc-pyrophosphate (PYP) scintigraphy is used to differentiate ATTR from other CA subtypes. We adapted the standardized uptake value (SUV) for Tc-PYP and proposed two quantitative indices, amyloid deposition volume (AmyDV) and total amyloid uptake (TAU). This study aimed to evaluate the utility of these quantitative indices in differentiating ATTR from non-ATTRs. Before the SUV measurement, the Becquerel calibration factor (BCF) of Tc was obtained by a phantom experiment. Thirty-two patients who had undergone hybrid SPECT/CT imaging 3 h after injection of Tc-PYP (370 MBq) were studied. CT attenuation correction for image reconstruction was applied in all. We calculated SUV, AmyDV, and TAU using a quantitative analysis software program for bone SPECT (GI-BONE) and analyzed AmyDV using two methods: threshold method (set 40%); and constant value method (average SUV of ribs). We assessed the diagnostic ability of heart-to-contralateral lung (H/CL) ratio, SUV, AmyDV, and TAU to differentiate ATTR from non-ATTR using receiver operating characteristic (ROC) analysis. Statistically significant differences in all quantitative indices were observed between ATTR and non-ATTR. The area under the curve of each quantitative index for discriminating between ATTR and non-ATTR were as follows: H/CL, 0.997; SUV, 0.953; SUV (M1), 0.964; SUV (M2), 0.969; AmyDV (M1), 0.875; AmyDV (M2), 0.974; and TAU, 0.974. The AmyDV (M2) had higher diagnostic ability than AmyDV (M1). Thus, TAU was calculated as AmyDV (M2) × SUV (M2). In the ROC curve, SUV, AmyDV, and TAU had almost the same diagnostic ability as H/CL in distinguishing ATTR from non-ATTRs. We propose two novel 3D-based quantitative parameters (AmyDV and TAU) that have almost equal ability to discriminate ATTR from non-ATTR.
Ryosuke Kasai and Hideki Otsuka : Noise Reduction Using Singular Value Decomposition with Jensen-Shannon Divergence for Coronary Computed Tomography Angiography, Diagnostics, Vol.13, No.6, 2023.
(Summary)
Coronary computed tomography angiography (CCTA) is widely used due to its improvements in computed tomography (CT) diagnostic performance. Unlike other CT examinations, CCTA requires shorter rotation times of the X-ray tube, improving the temporal resolution and facilitating the imaging of the beating heart in a stationary state. However, reconstructed CT images, including those of the coronary arteries, contain insufficient X-ray photons and considerable noise. In this study, we introduce an image-processing technique for noise reduction using singular value decomposition (SVD) for CCTA images. The threshold of SVD was determined on the basis of minimization of Jensen-Shannon (JS) divergence. Experiments were performed with various numerical phantoms and varying levels of noise to reduce noise in clinical CCTA images using the determined threshold value. The numerical phantoms produced 10% higher-quality images than the conventional noise reduction method when compared on a quantitative SSIM basis. The threshold value determined by minimizing the JS-divergence was found to be useful for efficient noise reduction in actual clinical images, depending on the level of noise.
Yuka Hiroshima, Youichi Otomi, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : F-FDG PET/CT in the Evaluation of Adult Alveolar Rhabdomyosarcoma., Molecular Imaging and Radionuclide Therapy, Vol.32, No.1, 62-64, 2023.
(Summary)
C-methionine PET/CT for accurately assessing the extent of alveolar rhabdomyosarcoma, especially in cases with intracranial infiltration or those approximating the brain.
Youichi Otomi, Saho Irahara, Hiroaki Inoue, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : Increased 18F-FDG Uptake in the Axillary Lymph Nodes of Vaccinated Side Associated with COVID-19 Vaccination, Molecular Imaging and Radionuclide Therapy, Vol.31, No.2, 169-171, 2022.
(Summary)
A 50-year-old female patient underwent (fluorine-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) following modified radical mastectomy for cancer of the left breast. Ten days before the PET/CT, the coronavirus disease-2019 (COVID-19) vaccine was injected intramuscularly into the right deltoid muscle. Increased (F-FDG uptake of maximum standardized uptake value (11.0) was observed in the lymph nodes of the right axilla, which had not been observed in the previous PET/CT. The size of the oval-shaped lymph nodes was up to approximately 11×9 mm; however, it was larger than that observed on the previous PET/CT. We contemplate that the increased (F-FDG uptake was a reactive change in the lymph nodes associated with the COVID-19 vaccine.
Nahomi Shono, Youichi Otomi, Hideki Otsuka, Takayoshi Shinya and Masafumi Harada : Multicystic Biliary Hamartoma With Xanthogranulomatous Inflammation on 18F-FDG PET/CT., Clinical Nuclear Medicine, Vol.47, No.10, 882-884, 2022.
(Summary)
A 70-year-old man with a liver tumor was pathologically diagnosed with multicystic biliary hamartoma with xanthogranulomatous inflammation. Plain CT revealed an inhomogeneous low-density liver tumor, measuring 43 × 35 mm. Dynamic contrast-enhanced CT revealed a cyst, measuring approximately 15 mm, with a ring-shaped enhancement, within the tumor. There was delayed enhancement on the outer portion of the tumor. Mild peripheral bile duct dilation was also observed. 18F-FDG PET/CT showed focal high uptake with an SUVmax of 5.2 near the cyst. The findings of this case mimicked that of intrahepatic cholangiocellular carcinoma.
Youichi Otomi, Yuta Arai, Maki Ohtomo, Saho Irahara, Kaori Terazawa, Michiko Kubo, Takashi Abe, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : Increased physiological [18F] FDG uptake in the liver and blood pool among patients with impaired renal function, Nuclear Medicine Review. Central & Eastern Europe, Vol.25, No.2, 95-100, 2022.
(Summary)
In the daily clinical course, the liver uptake may seem to be increased in patients with renal failure. The purpose of this study was to investigate whether or not the FDG uptake of the liver, and the FDG uptake of blood pool which is generally used as a reference site as well as liver, is increased in patients with renal failure. We retrospectively analyzed 233 patients who underwent FDG positron emission tomography/computed tomography (PET/CT). Renal failure is defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2. We compared the FDG uptake in the liver and mediastinal blood pool of 67 patients with impaired renal function to that in 166 patients with a normal renal function (eGFR ≥ 60 mL/min/1.73 m2). Correlations between the liver or mediastinal blood pool FDG uptake and the eGFR were also analyzed by Spearman's correlation test. Maximum and mean standardized uptake values (SUVmax and SUVmean, respectively) of the liver and the SUVmean of the mediastinal blood pool were 3.48 ± 0.57, 2.56 ± 0.37, and 1.90 ± 0.28 in the impaired renal function group, respectively, and 3.13 ± 0.45, 2.29 ± 0.33, and 1.66 ± 0.23, in the normal group, respectively. The SUVmax and SUVmean of the liver and SUVmean of the mediastinal blood pool in the impaired renal function group were significantly higher than those in the normal group (p < 0.001, < 0.001, and < 0.001, respectively). The SUVmax and SUVmean of the liver and SUVmean of the mediastinal blood pool of patients showed a significant negative correlation with the eGFR (Spearman's p = -0.25, -0.30, and -0.40, respectively, each p < 0.001). FDG uptake in both the liver and mediastinal blood pool was higher in patients with impaired renal function.
Moriaki Yamanaka, Shoichiro Takao, Hideki Otsuka, Youichi Otomi, Saho Irahara, Yamato Kunikane, Satoru Takashi, Airi Yamamoto, Masataka Sata and Masafumi Harada : The Utility of a Combination of <sup>99m</sup>Tc-MIBI Washout Imaging and Cardiac Magnetic Resonance Imaging in the Evaluation of Cardiomyopathy, Annals of Nuclear Cardiology, Vol.7, No.1, 8-16, 2021.
(Summary)
Background: In cardiomyopathy, 99mTc-MIBI washout can reflect mitochondrial dysfunction and late gadolinium enhancement (LGE) on cardiac magnetic imaging (MRI) is associated with tissue fibrosis. We sought to determine the relationship between 99mTc-MIBI uptake, 99mTc-MIBI washout, and LGE on MRI in patients with cardiomyopathy. Methods: Twenty-one patients underwent rest myocardial perfusion scintigraphy at 45 minutes (early) and 4 hours (delayed) after intravenous 99mTc-MIBI administration and cardiac MRI. We assessed myocardial perfusion, 99mTc-MIBI washout, and LGE. We divided the left ventricle (LV) wall into 16 segments using a polar map. Then, we classified each segment into 5 groups according to 99mTc-MIBI uptake in early-rest images and washout. Additionally, we created a contingency table based on LGE presence/absence in the groups. Results: We evaluated 336 segments in 21 patients. 99mTc-MIBI uptake was decreased in 168 segments in the early-rest 99mTc-MIBI images. 99mTc-MIBI washout was observed in 108 segments with either normal perfusion or reduced perfusion in the early-rest 99mTc-MIBI images. LGE was positive in 104 segments. A contingency table analysis with Fisher窶冱 exact test showed that LGE was observed significantly more frequently in the segments with decreased 99mTc-MIBI uptake (p < 0.001). In segments without a decreased 99mTc-MIBI uptake, there was a significant correlation between increased 99mTc-MIBI washout and the presence of LGE (p = 0.033). Conclusions: In cardiomyopathy, the mitochondrial dysfunction in the early stage is shown as 99mTc-MIBI washout, and fibrotic changes in the myocardium in advanced stages are shown as LGE on cardiac MRI. The severity of myocardial damage and the clinical stage of cardiomyopathy can be evaluated using multimodal imaging.
(Keyword)
<sup>99m</sup>Tc-MIBI / Cardiomyopathy / Late gadolinium enhancement (LGE) / Washout
Tamaki Otani, Hideki Otsuka, Kou Matsushita, Yoichi Otomi, Yamato Kunikane, Shota Azane, Masafumi Amano, Masafumi Harada and Hirokazu Miyoshi : Effect of different examination conditions on image quality and quantitative value of amyloid positron emission tomography using F-flutemetamol., Annals of Nuclear Medicine, Vol.35, No.9, 1004-1014, 2021.
(Summary)
The recommended start time for F-flutemetamol amyloid positron emission tomography (PET) examination is 60-120 min after F-flutemetamol injection, while an acquisition time of 10-30 min is generally recommended. We aimed to elucidate the effects of different examination conditions on image quality, diagnostic ability, and quantitative value of amyloid PET using F-flutemetamol. We acquired data on a Discovery PET/computed tomography 710 scanner using Hoffman brain and pillar phantoms with 20 MBq of F for 30 min. The images were reconstructed into 10-, 20-, and 30-min periods. The ordered subset-expectation maximization algorithm was used for image reconstruction, which uses a 2- or 4-mm Gaussian filter and a combination of iteration and subset numbers. The percentage contrast and coefficient of variation (CV; as the image noise) were used as physical evaluation indices for reconstructed images, and images with superior contrast and low image noise were selected for clinical evaluation. The imaging data of 15 symptomatic patients (n = 7 and n = 8 for positive and negative diagnoses of Alzheimer's disease, respectively) were reconstructed under the phantom study conditions. Radiographers visually evaluated and ranked the clinical images based on the overall contrast and image noise, and nuclear medicine specialists diagnosed Alzheimer's disease. We compared the standardized uptake value ratio (SUVR) obtained with different acquisition conditions. The basic study using the phantom revealed high convergence of contrast and image noise in five patterns of acquisition time and filter strengths. Regarding visual evaluation, the use of a 2-mm Gaussian filter caused difficulties in diagnosis because the brain parenchymal accumulation was mottled with high image noise. Differences in image quality and diagnostic ability due to different examination times were not significant. Differences in the SUVR were not significant in patients with a negative Alzheimer's disease diagnosis; in patients with a positive diagnosis, the SUVR showed significant fluctuation depending on the acquisition conditions. The differences in image quality and diagnostic performance due to the differences in 10-min acquisition time were not significant; however, of note, SUVR showed significant fluctuation depending on the acquisition conditions in patients diagnosed with Alzheimer's disease.
Ryota Bando, Hideki Otsuka, Tamaki Otani, Noritake Matsuda, Shota Azane, Yamato Kunikane, Yoichi Otomi, Wataru Sako, Yuishin Izumi and Masafumi Harada : A new quantitative index in the diagnosis of Parkinson syndrome by dopamine transporter single-photon emission computed tomography., Annals of Nuclear Medicine, Vol.35, No.4, 504-513, 2021.
(Summary)
Dopamine transporter single-photon emission computed tomography (DAT SPECT) has been widely used to diagnose Parkinson syndrome. Using the standardized uptake value (SUV) of DAT SPECT, we propose "functional dopamine transporter volume (f-DTV)" as a new quantitative index to evaluate the three-dimensional volume of functional dopamine transporters and assess its diagnostic ability in differentiating dopaminergic neurodegenerative diseases (dNDD) from non-dNDD. Seventy-nine patients were enrolled (42 dNDD, 37 non-dNDD; 38 men; age 24-88 years). We analyzed seven quantitative indices. The specific binding ratio (SBR) was calculated using a program specialized for DAT SPECT (SBR_Bolt). The SUVmax, SUVpeak, and SUVmean were calculated using a quantification program for bone SPECT. SBR_SUV was calculated by dividing striatal SUVmean by the average of background SUVmean. The cutoff value of the active dopamine transporter level was examined using three methods (threshold of 40% of SUVmax, SUV 2, and SUV 3) to calculate the active dopamine transporter volume (ADV). The f-DTV was calculated by multiplying ADV and SUV. We assessed the correlations between SBR_Bolt and SBR_SUV, and compared the mean value of each index between the dNDD and non-dNDD groups. The abilities of SBR_Bolt, SBR_SUV, SUVmax, SUVpeak, SUVmean, ADV, and f-DTV in differentiating dNDD from non-dNDD were determined by the area under the receiver operating curve (AUC) generated by the receiver operating characteristics analysis. The SBR_Bolt and SBR_SUV highly correlated with each other (r = 0.71). The cutoff value of the active dopamine transporter level was determined as SUV 3. All seven quantitative indices showed lower values in the dNDD group than in the non-dNDD group, and the difference between the two groups was statistically significant (p < 0.05). Sensitivity, specificity, and AUC of f-DTV were slightly lower than those of SBR_Bolt (71%, 79%, and 0.81, respectively, for f-DTV, and 81%, 84%, 0.88, respectively, for SBR_Bolt). The difference in AUC between f-DTV and SBR_Bolt was not statistically significant. This study demonstrates the utility of f-DTV as a novel quantitative index for evaluating the three-dimensional volume of functional dopamine transporters, and that f-DTV has almost the same diagnostic ability to differentiate dNDD from non-dNDD using DAT SPECT.
(Keyword)
Adult / Aged / Aged, 80 and over / Biological Transport / Diagnosis, Differential / Dopamine Plasma Membrane Transport Proteins / female / Humans / Iodine Radioisotopes / male / Middle Aged / Nortropanes / Parkinson's disease / Phantoms, Imaging / ROC Curve / Retrospective Studies / Tomography, Emission-Computed, Single-Photon
Youichi Otomi, Nahomi Shono, Hajime Onishi, Ryota Mitsuhashi, Saya Matsuzaki, Yukiko Takaoka, Hideaki Enomoto, Yuko Sakamoto, Mihoko Sasahara, Takashi Abe, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : A reduced physiological 18 F-fluorodeoxyglucose uptake in the brain and liver caused by malignant lymphoma being deprived of the tracer, The Journal of Medical Investigation : JMI, Vol.68, No.1. 2, 181-185, 2021.
(Summary)
Purpose : To investigate whether or not the physiological brain and liver FDG uptake are decreased in patients with highly accelerated glycolysis lesions. Methods : We retrospectively analyzed 51 patients with malignant lymphoma. We compared the FDG uptake in the brain and liver of the patients with that in a control group. In 24 patients with a complete response (CR) or partial response (PR) to treatment, we compared the brain and liver uptake before and after treatment. Results : The maximum standardized uptake value (SUVmax) and total glycolytic volume (TGV) of the brain as well as the SUVmax and mean standardized uptake value (SUVmean) of the liver in malignant lymphoma patients were 13.1 ± 2.3, 7386.3 ± 1918.4, 3.2 ± 0.5, and 2.3 ± 0.4, respectively ; in the control group, these values were 14.9 ± 2.4, 8566.2 ± 1659.5, 3.4 ± 0.4, and 2.5 ± 0.3, respectively. The SUVmax and TGV of the brain and the SUVmean of the liver in malignant lymphoma patients were significantly lower than the control group. The SUVmax and TGV of the brain after treatment were significantly higher than before treatment. Both the SUVmax and SUVmean of liver after treatment were higher than before treatment, but not significant. Conclusion : A decreased physiological brain and liver FDG uptake is caused by highly accelerated lesion glycolysis. J. Med. Invest. 68 : 181-185, February, 2021.
Takayoshi Shinya, Otomi Yoichi, Toshihiko Nishisho, B Beuthien-Baumann, Saho Irahara, Michiko Kubo, Hideki Otsuka, Yoshimi Bando, Koichi Sairyo and Masafumi Harada : Clinical application of dynamic 18F-fluorodeoxyglucose positron-emission tomography / computed tomography in the differential diagnoses of musculoskeletal lesions, The Journal of Medical Investigation : JMI, Vol.68, No.1. 2, 96-104, 2021.
(Summary)
<p>We aimed to assess the differential diagnostic efficacy of dynamic F-18 fluorodeoxyglucose (FDG) positron emission tomography / computed tomography (PET / CT) and to evaluate the appropriate scan timings for diagnosis of musculoskeletal lesions (MSLs). Dynamic scans (5-15 [phase 1], 15-25 [phase 2], and 25-35 [phase 3] min after F-18 FDG injection) and dual-time-point scans (1 and 2 h after injection) were acquired for 23 MSLs [4 benign MSLs (BMSLs). 10 primary malignant musculoskeletal tumors (PMMSTs), and 9 metastatic musculoskeletal tumors (MMSTs)]. We compared the maximum standardized uptake values (SUVmax) and corresponding retention indices for dynamic (RI-SUVdyn) and dual-time-point (RI-SUVdual) scans and evaluated diagnostic efficacy using receiver operating characteristic (ROC) curve analyses. The SUVmax gradually decreased or was almost identical with minimal fluctuation in 3 BMSLs and 1 PMMST. SUVmax increased over time after phase 2 in 18 malignant MSLs (MMSLs). There were significant differences in SUVmax (for all time phases) and RI-SUV dual between BMSLs and MMSLs and between PMMSTs and MMSTs. In the ROC analyses, the areas under the curve for SUV in phases 2 and 3 were highest for differentiating BMSLs from MMSLs and PMMSTs from MMSTs, respectively. Dynamic F-18 FDG PET / CT is valuable for diagnosis of musculoskeletal lesions. J. Med. Invest. 68 : 96-104, February, 2021</p>
(Keyword)
bone and soft tissue tumors / dynamic scan / musculoskeletal lesion / positron emission tomography computed tomography / sarcoma
Hiroaki Toba, Naoya Kawakita, Mika Takashima, Daisuke Matsumoto, Hiromitsu Takizawa, Hideki Otsuka and Akira Tangoku : Diagnosis of recurrence and follow-up using FDG-PET/CT for postoperative non-small-cell lung cancer patients, General Thoracic and Cardiovascular Surgery, Vol.69, No.2, 311-317, 2021.
(Summary)
There is currently no consensus regarding the best program for postoperative follow-up and surveillance after a curative resection for non-small-cell lung cancer (NSCLC) patients. We examined the diagnostic capability of F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for detecting recurrence in postoperative NSCLC patients, and we evaluated the results of postoperative surveillance using FDG-PET/CT in asymptomatic patients. Between 2005 and 2013, 496 FDG-PET/CT examinations were performed to detect recurrences for 187 NSCLC patients who had undergone potentially curative operations at our institution. Follow-up FDG-PET/CT was performed ≥ 1 × /year in principle in 172 asymptomatic patients without clinical or radiological evidence of recurrence, and the results were retrospectively reviewed. FDG-PET/CT correctly diagnosed recurrence in 46 of 47 (97.9%) patients and 68 of 69 (98.6%) recurrent sites. The following were obtained: 97.9% sensitivity, 97.1% specificity, 92.0% positive predictive value, 99.3% negative predictive value, and 97.3% accuracy. In six patients, other diseases were detected and treated appropriately. In asymptomatic patients, the detection rate of recurrence in the stage III group was significantly higher than the detection rates in the stage I and II groups, and FDG-PET/CT performed ≤ 3 years post-resection detected significantly more FDG-positive lesions compared to that performed after 4 years. FDG-PET/CT is very useful for detecting recurrence in NSCLC patients after a potentially curative operation. It might be sufficient to perform follow-up FDG-PET/CT until 3 years post-resection for advanced-stage patients. Further randomized clinical trials are needed to determine whether the early detection of recurrences leads to better prognoses.
Takayoshi Shinya, Youichi Otomi, Toshihiko Nishisho, Bettina Beuthien-Baumann, Michiko Kubo, Hideki Otsuka, Yoshimi Bando, Hiroaki Yanagawa, Koichi Sairyo and Masafumi Harada : Preliminary clinical assessment of dynamic carbon-11 methionine positron-emission tomography/computed tomography for the diagnosis of the pathologies in patients with musculoskeletal lesions: a prospective study., European Journal of Hybrid Imaging, Vol.26, No.4, 15, 2020.
(Summary)
Dynamic C-11 MET PET scans have the potential to be good predictors of discriminating MSLs in patients with primary unknown MSLs in clinical practice.
Naoya Kawakita, Hiroaki Toba, Yukikiyo Kawakami, Hiromitsu Takizawa, Yoshimi Bando, Hideki Otsuka, Daisuke Matsumoto, Mika Takashima, Mitsuhiro Tsuboi, Mitsuteru Yoshida, Kazuya Kondo and Akira Tangoku : Use of a prognostic risk score that aggregates the FDG-PET/CT SUVmax, tumor size, and histologic group for predicting the prognosis of pStage I lung adenocarcinoma, International Journal of Clinical Oncology, Vol.25, No.6, 1079-1089, 2020.
(Summary)
pStage I includes clinicopathologically diverse groups. This study aimed to identify the prognostic factors for pStage I lung adenocarcinoma. We retrospectively reviewed 208 patients with pStage I adenocarcinomas who underwent curative resection in our institute between 2006 and 2013. The maximum standardized uptake value (SUVmax) on [F18]-fluoro-deoxy-D-glucose positron emission tomography-computed tomography (PET/CT) was evaluated. Adenocarcinomas were categorized into the following histologic groups: group 0 (minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma), group 1 (papillary predominant adenocarcinoma), and group 2 (acinar predominant adenocarcinoma and all the remaining subtypes). We assessed the relationship between disease-free survival (DFS) and clinicopathological factors. Multivariate analysis of DFS demonstrated that SUVmax > 3.0 (p < 0.001), total tumor size > 20 mm (p = 0.016), and histologic groups (p < 0.05) were independent prognostic factors. The prognostic risk score (PRS) was calculated using the following equation: PRS = SUVmax (≤ 3.0: 0 point, > 3.0: 2 points) + total tumor size (≤ 20 mm: 0 point, > 20 mm: 1 point) + histologic group (group 0: 0 point, group 1: 1 point, group 2: 2 points). Patients were divided into the following three risk groups: low-risk (PRS 0-2 points, n = 136), intermediate-risk (PRS 3-4 points, n = 49), and high-risk groups (PRS 5 points, n = 13). The 5-year DFS rates were 93.2%, 50.6%, and 30.8% for the low-, intermediate-, and high-risk groups, respectively (p < 0.001). The PRS aggregating the FDG-PET/CT SUVmax, total tumor size, and histologic group predicts the prognosis of pStage I lung adenocarcinoma.
Takaaki Isayama, Sadamitsu Nishihara and Hideki Otsuka : Proposal of a new method to prove that unnecessary information is not drawn on the image using statistical analysis, Radiological Physics and Technology, Vol.12, No.2, 156-160, 2019.
(Summary)
The purpose of this study is to propose a new method of image evaluation using statistical analysis. We used the Sign test and the Wilcoxon test to analyze the statistical significance of image differences. Using this method, we evaluated whether the small electrode of the DAP meter appears in the X-ray image. Two observed values, which were obtained by averaging all values under all exposure conditions, were compared. All the observation tests showed the same sign. Thus, the results proved that the small electrode of the DAP meter is not present on the image. Using this method, it became possible to prove that the electrode was not depicted, which was impossible to determine using conventional methods. The method combining both the Sign test and the Wilcoxon test can be useful in image evaluation.
(Keyword)
Dose area product (DAP) meter / Observer test / Sign test / Wilcoxon test / Small electrode
Nagahisa Murakami, Wataru Sako, Shotaroh Haji, Takahiro Furukawa, Yoichi Otomi, Hideki Otsuka, Yuishin Izumi, Masafumi Harada and Ryuji Kaji : Potential Utility of 123I-MIBG Scintigraphy as a Predictor of Falls in Parkinson's Disease, Frontiers in Neurology, Vol.10, 376, 2019.
(Summary)
Falls are associated with poor prognosis in patients with Parkinson's disease (PD). Although several factors related to falls were reported in patients with PD, objective predictors of falls are not identified. We aimed to determine whether I-meta-iodobenzylguanidine (MIBG) cardiac scintigraphy could be a useful biomarker to predict falls. Forty-five patients with PD were enrolled in this study. These subjects were followed up more than 5 years after MIBG scintigraphy and were divided into two groups: one with decreased uptake of MIBG and the other without decreased uptake of MIBG. The cut-off value for the delayed heart-to-mediastinum ratio was 1.8. Kaplan-Meier analysis and a log-rank test were performed to test the predictive power of MIBG cardiac scintigraphy for falls. Univariate analysis was selected because we did not have appropriate data for adjustment, such as motor and cognitive assessment. The group with decreased uptake of MIBG had a significantly higher incidence of falls than that without decreased uptake of MIBG ( = 0.022, log-rank test). Although the limitations of this study were lack of several key factors including motor and cognitive assessment, MIBG cardiac scintigraphy may be used to predict falls in patients with PD.
Yuki Kanazawa, Yuki Matsumoto, Masafumi Harada, Hiroaki Hayashi, Tsuyoshi Matsuda and Hideki Otsuka : Appropriate echo time selection for quantitative susceptibility mapping., Radiological Physics and Technology, Vol.12, 185-193, 2019.
(Summary)
The purpose of our study was to clarify the dependence of quantitative susceptibility mapping (QSM) on echo time (TE). We constructed a phantom consisting of six tubes; three tubes were filled with different concentrations (0.5, 1.0, and 2.5 mM) of gadopentetate dimeglumine (Gd-DTPA), and three were filled with different concentrations (100, 200, and 350 mg/mL) of calcium hydroxyapatite. Real and imaginary images from multi-echo spoiled gradient-echo data (12 echoes) were acquired. We then used four datasets with three serial echoes. The QSM procedure consists of four steps: field map estimation, phase unwrapping, background removal, and dipole inversion. For each sample, we compared the measured mean susceptibility value with the theoretical susceptibility value and conducted a linear regression analysis. Accordingly, the relationship between the measured susceptibility and concentration of Gd-DTPA was shown to agree well with the theoretical values (TEs = 16.4, 20.8, and 25.2 ms; slope = 0.24, R = 1.00). Furthermore, the relationship between the measured susceptibility and concentration of hydroxyapatite also showed good linearity (TEs = 16.4, 20.8, and 25.2 ms; slope = - 0.00121, R = 1.00). In conclusion, the optimization of the TE in QSM makes it possible to obtain more detailed information regarding the susceptibility of biomaterials.
Tamaki Otani, Kazuya Kondo, Hiromitsu Takizawa, Koichiro Kajiura, Haruhiko Fujino, Hideki Otsuka and Hirokazu Miyoshi : Noninvasive monitoring of cisplatin and erlotinib efficacy against lung cancer in orthotopic SCID mouse models by small animal FDGPET/CT and CT., Oncology Reports, Vol.41, No.1, 447-454, 2019.
(Summary)
We established patient-like models of lung cancer metastasis by orthotopically implanting human non-small cell lung cancer cell lines into SCID mice. We evaluated the utilities of small-animal computed tomography (CT) and positron-emission tomography-computed tomography (PET/CT) in these models to non-invasively and repeatedly monitor the anticancer effects of cisplatin and erlotinib. We orthotopically implanted three non-small cell lung cancer cell lines, A549, FT821 and PC-9, into SCID mice. These mice were then divided into three groups: Control, cis-diamminedichloroplatinum (II) (CDDP) (7-mg/kg CDDP, single administration intraperitoneally), and erlotinib (25 mg/kg erlotinib/day, oral administration 5 days/week). After treatment initiation, we repeatedly performed PET/CT and CT measurements and assessed anticancer effects based on tumor volumes and FDG uptake. A549 tumors were not affected by CDDP or erlotinib. FT821 tumors were highly responsive to CDDP. PC-9 tumors, which have an epidermal growth factor receptor mutation, were highly responsive to erlotinib. Histological results and metastatic rates correlated with the anticancer effects shown by CT. In our orthotopic SCID mouse lung cancer models, 18FDG-PET/CT and CT imaging non-invasively and repeatedly monitored the efficacies of cisplatin and erlotinib against not only implanted tumors, but also mediastinal lymph node metastases.
Youichi Otomi, Hideki Otsuka, Kaori Terazawa, Moriaki Yamanaka, Yuki Obama, Maki Arase, Maki Otomo, Saho Irahara, Michiko Kubo, Naoto Uyama, Takashi Abe and Masafumi Harada : The diagnostic ability of SPECT/CT fusion imaging for gastrointestinal bleeding: a retrospective study., BMC Gastroenterology, Vol.18, No.1, 183, 2018.
(Summary)
Blood loss from the gastrointestinal tract can be an acute and life-threatening event. For the treatment of gastrointestinal bleeding, it is important to accurately detect gastrointestinal bleeding and to localize the sites of bleeding. The purpose of this study was to retrospectively assess the capabilities of SPECT/CT in the diagnosis of gastrointestinal bleeding by a comparison with planar imaging alone as well as planar and SPECT. We conducted a retrospective analysis of 20 patients (21 examinations) who underwent gastrointestinal bleeding scintigraphy in the past 7ears and in whom the bleeding site was identified by endoscopy or capsule endoscopy, or in whom no evidence of gastrointestinal bleeding was identified during the clinical course. Five patients (5 examinations) were diagnosed by planar imaging (planar group). Eight patients (9 examinations) were diagnosed by planar imaging and SPECT (planar + SPECT group). Seven patients (7 examinations) were diagnosed by planar imaging and SPECT/CT (planar + SPECT/CT group). We calculated the diagnostic ability of each method in detecting the presence of bleeding, as well as the ability of each method to identify the sites of bleeding. The sensitivity, specificity, and accuracy of the methods were compared. The diagnostic ability of the three imaging methods in detecting the presence of gastrointestinal bleeding was as follows. Planar imaging showed 100% sensitivity (3/3), 100% specificity (2/2), and 100% accuracy (5/5). Planar + SPECT imaging showed 85.7% sensitivity (6/7), 100% specificity (2/2), and 88.9% accuracy (8/9). Planar + SPECT/CT imaging showed 100% sensitivity (6/6), 100% specificity (1/1), and 100% accuracy (7/7). The diagnostic ability of the three modalities in detecting the site of bleeding was as follows: planar, 33.3% (1/3); planar + SPECT, 71.4% (5/7); and planar + SPECT/CT, 100% (6/6). All 3 imaging methods showed good accuracy in detecting the presence of gastrointestinal bleeding. The addition of SPECT or SPECT/CT made the anatomical position of the uptake clear and contributed to the localization of the site of gastrointestinal bleeding. Planar + SPECT/CT imaging therefore showed the highest diagnostic ability for detecting the site of gastrointestinal bleeding.
Naoto Uyama, Hideki Otsuka, Takayoshi Shinya, Youichi Otomi, Masafumi Harada, Wataru Sako, Yuishin Izumi, Ryuji Kaji, Yuya Watanabe, Satoru Takashi and Yamato Kunikane : The utility of the combination of a SPECT study with [123I]-FP-CIT of dopamine transporters and [123I]-MIBG myocardial scintigraphy in differentiating Parkinson disease from other degenerative parkinsonian syndromes., Nuclear Medicine Communications, Vol.38, No.6, 487-492, 2017.
(Summary)
Molecular imaging of nigrostriatal dopamine transporters (DAT) and sympathetic cardiac innervation with single-photon emission computed tomography (SPECT) are useful tools for differentiating idiopathic Parkinson disease (PD) from other degenerative parkinsonian syndromes (non-PD). Nevertheless, these modalities are often insufficient for achieving a definite diagnosis. The aims of this study were to evaluate the diagnostic accuracy of the combination of these tools. The SPECT radiotracers [I]-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)-nortropane (FP-CIT) and meta-[I]-iodobenzylguanidine (MIBG) were used to research presynaptic dopaminergic projections (DAT SPECT) and myocardial adrenergic innervation (MIBG scintigraphy), respectively. PD patients (n=15; age: 61.5±13.6 years) and non-PD patients (n=19; age: 62.6±14.2 years) who underwent both tests were enrolled in this study. Receiver-operating characteristic analyses were used to set the cutoff values of the specific binding ratio in DAT SPECT and the heart to mediastinum ratio in delayed scan in MIBG scintigraphy for differentiating PD from non-PD. We calculated the sensitivity, specificity, and test accuracy of the individual methods and also the combination of these two modalities. When DAT SPECT and MIBG scintigraphy were used individually, they showed mild accuracy in differentiating PD from non-PD (DAT, 67.6%; MIBG, 67.6%). The combination of the two approaches using cutoff values of less than 3.24 for the specific binding ratio and less than 2.745 for the delayed heart to mediastinum ratio enabled more accurate differentiation between PD and non-PD. The accuracy of these indices in distinguishing PD from non-PD was 79.4%. These results suggested that the combination of DAT SPECT and MIBG scintigraphy may improve the diagnostic accuracy in differentiating PD from non-PD.
Youichi Otomi, Takayoshi Shinya, Hideki Otsuka, Terazawa Kaori, Irahara Saho, Nagase Saki, Takahashi Ayaka, Michiko Kubo and Masafumi Harada : Increased (18)F-fluorodeoxyglucose accumulation in bilateral adrenal glands of the patients suffering from vasovagal reaction due to blood vessel puncture., Annals of Nuclear Medicine, Vol.30, No.7, 501-505, 2016.
(Summary)
The purpose of the study was to evaluate the hypothesis that patients having a vasovagal reaction (VVR) after blood vessel puncture show increased FDG accumulation in bilateral adrenal glands. Over the past 8 years, 26 patients experienced a VVR after blood vessel puncture following intra-venous injection of FDG at our institution. Of the 26 patients, 16 underwent multiple-occasion FDG-PET/CT scans while suffering a VVR at only one examination. All 16 patients had no morphological abnormality in the adrenal glands on FDG-PET/CT and follow-up examination. For the 16, we retrospectively reviewed the FDG-PET/CT scan with respect to the adrenal glands and compared the result to that for the FDG-PET/CT scan of the same patient when there was no VVR event. We used both visual analysis and semi-quantitative analysis employing either maximum standardized uptake value (SUVmax) or adrenal-to-liver (A/L) SUVmax ratio. On visual analysis of the FDG-PET/CT with VVR, accumulations in both of the adrenal glands was judged positive, defined as higher than the hepatic accumulation, in 84 % of the cases. The SUVmax in the right adrenal gland was 2.79 ± 0.69 with VVR and 1.92 ± 0.33 without VVR; this value in the left adrenal gland was 3.07 ± 0.71 with VVR and 2.05 ± 0.39 without. Mean SUVmax of both adrenal glands was 2.93 ± 0.66 with VVR and 1.98 ± 0.35 without. The A/L SUVmax ratio in the right adrenal gland was 1.02 ± 0.26 with VVR and 0.69 ± 0.11 without; this value in the left was 1.11 ± 0.23 with VVR and 0.74 ± 0.15 without. The mean A/L SUVmax ratio of both adrenal glands was 1.06 ± 0.24 with VVR and 0.72 ± 0.13 without. Each parameter with VVR was significantly higher than that without. For the two adrenal glands, the mean SUVmax with VVR was 48 % higher than that without VVR. We confirmed the hypothesis that patients having a VVR after blood vessel puncture show increased FDG accumulation in their bilateral adrenal glands. This may reflect hyper-metabolism of the adrenal glands in synthesizing and secreting catecholamine.
Koji Nakaya, Hideki Otsuka, Kazuya Kondo, Tamaki Otani and Motoi Nagata : Tumor growth-inhibitory effect of an angiotensin-converting enzyme inhibitor (captopril) in a lung cancer xenograft model analyzed using 18F-FDG-PET/CT., Nuclear Medicine Communications, Vol.37, No.2, 139-146, 2016.
(Summary)
We administered an angiotensin-converting enzyme inhibitor (captopril) to mice implanted with a human lung adenocarcinoma epithelial cell line (A549 cells) and investigated the tumor growth-inhibitory effect of captopril from the viewpoint of glucose metabolism using (18)F-fluorodeoxyglucose ((18)F-FDG)-PET/CT. Subcutaneous implantation of A549 cells (1.9×10(6) cells) was carried out in the lower right flank of mice. Fifteen days after the transplantation of A549 cells, mice (six in each group) were treated with captopril (3.0 mg/mouse) or saline (1000 μl/mouse) for 5 days. We performed (18)F-FDG-PET/CT imaging of the mice before and after the treatment and evaluated the degree of (18)F-FDG accumulation in tumors. In both groups (the captopril-administrated and control groups), values for the metabolic tumor volume (MTV), maximum standardized uptake value, total lesion glycolysis, and tumor volume after treatment had a tendency to increase. However, tumor growth was suppressed in the captopril-administrated group compared with the control group. In terms of the growth rate, the MTV and tumor volume were significantly different (P<0.05). It was found that captopril exerted a potential tumor growth-inhibitory effect; this was because the captopril-administrated group showed low values of MTV, maximum standardized uptake value, total lesion glycolysis, and tumor volume in comparison with the control group.
Tamaki Otani, Hideki Otsuka, Kazuya Kondo, Hiromitsu Takizawa, Motoi Nagata, Mina Kishida and Hirokazu Miyoshi : Utility of respiratory-gated small-animal PET/CT in the chronologic evaluation of an orthotopic lung cancer transplantation mouse model., Radiological Physics and Technology, Vol.8, No.2, 266-277, 2015.
(Summary)
Our aim in this study was to clarify the effects of respiratory-gated PET in the evaluation of lung cancer according to the (18)F-FDG uptake in an orthotopic transplantation mouse model. We created such a model, and we performed PET/CT. The mice were divided into two groups according to tumor volume: a small-tumor group (<20 mm(3)) and a large-tumor group (>20 mm(3)). We reconstructed the following conditions based on list-mode data: non-gated (3D) images and gated (4D) images, divided based on the respiratory cycle (expiration phase, stable phase, and inspiration phase). We calculated the maximum standardized uptake values (SUVmax) in each phase. We used the % difference [= (4D SUVmax - 3D SUVmax)/3D PET SUVmax × 100 (%)] to evaluate the differences in the 4D SUVmax and 3D SUVmax. The 4D SUVmax values were significantly higher than the 3D SUVmax, regardless of the tumor size. The % difference for the small tumors was greater than that for the large tumors, and it was highest in the stable phase. We conclude that the SUVmax in the stable phase under respiratory-gated PET are the most reliable. The SUVmax observed under non-gated PET are considered to be more frequently underestimated in cases involving small tumors than in those involving large tumors. In the chronologic study evaluating the time course of tumor development, the size of the tumor is small in early stage, and respiratory-gated PET is effective in reducing the underestimation of such tumors caused by respiratory motion.
Sadamitsu Nishihara, Yuki Yamashita, Naoki Kawai and Hideki Otsuka : Usefulness of the SNR Using the Subtraction Method and Image Visibility Using the Howlett Chart Method in X-ray Fluoroscopic System, Open Journal of Medical Imaging, Vol.4, No.2, 65-71, 2014.
(Summary)
X-ray fluoroscopy has not only been used for diagnoses but also treatment, as in interventional radiology. The aim of this study is to assess the usefulness of the signal-to-noise ratio (SNR) using the subtraction method, which is used in the quality assurance/quality control (QA/QC) of magnetic resonance imaging (MRI) equipment, and image visibility using the Howlett chart method in the fluoroscopic examination. The fluoroscopy unit has a detector with an image intensifier and a color liquid crystal display. A 2620 dosimeter and an ionization chamber were selected for the dose measurement. Fluoroscopic images for visual and physical evaluations were collected as dynamic data. The skin surface absorbed dose rates in each tube current were measured using a dosimeter. The SNR using the subtraction method and image visibility using the Howlett chart method were examined. The results from both indicate that as the SNR improves, visual evaluation increases, but the rate of increase gradually saturate. Therefore, physical and visual evaluations are possible with the SNR using the subtraction method and the image visibility using the Howlett chart method.
(Keyword)
X-ray fluoroscopic system / signal-to-noise ratio / Howlett chart / visibility
Mohamed Mokhtar, Kazuya Kondo, Hiromitsu Takizawa, Tamaki Otani, Hideki Otsuka, Hitoshi Kubo, Koichiro Kajiura, Yasushi Nakagawa, Yukikiyo Kawakami, Mitsuteru Yoshida, Haruhiko Fujino, Shoji Sakiyama and Akira Tangoku : Non-invasive monitoring of anticancer effects of cisplatin on lung cancer in an orthotopic SCID mouse model using [¹⁸F] FDG PET-CT., Oncology Reports, Vol.31, No.5, 2007-2014, 2014.
(Summary)
Positron emission tomography-computed tomography (PET-CT) with [18F] fluorodeoxyglucose (FDG) has recently been applied for evaluating tumor response to anticancer therapy. The aim of the present study was to evaluate the utility of FDG PET-CT in monitoring non-invasively and repeatedly the inhibitory effect of cisplatin (CDDP) on an orthotopic lung cancer model. Validation of in vivo FDG uptake in human lung cancer Ma44-3 cell line in an orthotopic SCID mouse model was carried out. Next, we assessed the use of FDG PET-CT to monitor the response of orthotopic lung cancer to the anticancer effect of CDDP. SCID mice were divided into the CDDP group (7 mg/kg single dose intraperitoneally) and the control group. Tumor volume and maximal standardized uptake value (SUV max) were calculated for all mice. All mice were sacrificed for histopathologic analysis. Validation of FDG PET-CT showed that tumor volume and SUV max were significantly correlated with postmortem tumor length measured in specimens (P=0.023) and (P=0.012), respectively, and there was a significant correlation between SUV max and tumor volume (P=0.048). Response monitoring showed that significant growth inhibition by CDDP in the form of SUV max of the CDDP group was significantly lower than that of the control group on day 8 (P=0.02) and on day 13 (P=0.003). Tumor volume of the CDDP group was significantly lower than that of the control group on day 13 (P=0.03). The present study supports using FDG PET-CT in monitoring tumor progression and therapeutic response of lung cancer in an orthotopic model non‑invasively and repeatedly.
Hitoshi Kubo, Tamaki Otani, Hideki Otsuka and Masafumi Harada : The impact of self-shielded cyclotron operation on small-animal PET/CT equipment installed nearby, on the floor just above., The Journal of Medical Investigation : JMI, Vol.61, No.1-2, 46-52, 2014.
(Summary)
The purpose of this study was to evaluate the impact of a cyclotron on small-animal PET equipment installed directly above the cyclotron. The cyclotron equipment was HM-12, which has two targets, and the PET/CT equipment was Inveon. The equipment was installed in conformity to Japanese law and regulations. Before installation of the PET/CT equipment, the radiation dose, radio waves, and static and fluctuating magnetic fields were measured at the position where it would be placed, both when the cyclotron was in use and when it was not in use. After installation of the PET/CT, natural background and emission counts were measured at the same place under the same conditions. An increase of radiation dose was observed when the target nearest the PET equipment was used. There were no distinct effects of radio waves or static and fluctuating magnetic fields. A significant increase of emission counts, approximately 300 cpm, was observed when the nearest target was used. Though radio waves and static and fluctuating magnetic fields generated by running cyclotron had no influence, a significant increase in emission count was observed. Careful attention should be paid to this influence when very low-radioactivity PET measurements are done.
(Keyword)
Animals / Cyclotrons / Equipment Failure / Japan / Magnetic Fields / Positron-Emission Tomography / Radiation Dosage / Radio Waves / Static Electricity / Tomography, X-Ray Computed
Youichi Otomi, Hideki Otsuka, Kaori Terazawa, Hayato Nose, Michiko Kubo, Kenji Matsuzaki, Hitoshi Ikushima, Yoshimi Bando and Masafumi Harada : Comparing the performance of visual estimation and standard uptake value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography for detecting malignancy in pancreatic tumors other than invasive ductal carcinoma., The Journal of Medical Investigation : JMI, Vol.61, No.1-2, 171-179, 2014.
(Summary)
The utility of FDG PET/CT for the detection and evaluation of invasive ductal carcinoma has been widely reported, but a few studies have assessed the utility of FDG PET/CT to detect malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma. To compare the diagnostic performance of visual estimation with the semi-quantitative scores of FDG PET/CT for detecting malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma. Images of pathologically proven pancreatic lesions from 32 patients were retrospectively evaluated: 14 benign lesions, 7 borderline (low malignant) lesions, and 11 malignant lesions. The average scores from visual estimation by the two observers were compared to two semi-quantitative analyses of FDG uptake in the lesions, namely the maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean). Visual analysis value, SUVmax and SUVmean were 0.33 ± 0.21, 1.8 ± 0.7 and 1.5 ± 0.7 for the benign lesions, 0.70 ± 0.28, 5.0 ± 2.6 and 3.1±1.7 for the borderline lesions, and 0.73 ± 0.18, 4.7 ± 2.5 and 3.2 ± 1.6 for the malignant lesions, respectively. Receiver operating characteristic analysis revealed the areas under the curves for detecting non-benign (malignant or borderline) lesions through visual analysis, SUVmax, and SUVmean were 0.914, 0.954, and 0.875, respectively. For a variety of pancreatic lesions other than invasive ductal carcinoma, visual analysis and semi-quantitative analyses all showed strong diagnostic performance. However, semi-quantitative analysis with SUVmax proved to be the most effective method for detecting non-benign pancreatic lesions.
Hayato Nose, Hideki Otsuka, Youichi Otomi, K Terazawa, Shoichiro Takao, Seiji Iwamoto, Takashi Iwase, Hirotsugu Yamada, Masataka Sata and Masafumi Harada : The physiological uptake pattern of (18)F-FDG in the left ventricular myocardium of patients without heart disease., The Journal of Medical Investigation : JMI, Vol.61, No.1, 2, 53-58, 2014.
(Summary)
Purpose: The purpose of this study was to evaluate the physiological uptake pattern of 18F-FDG in the left ventricular myocardium of patients under preparation for tumor FDG-PET. Patients and Methods: We enrolled 188 patients without cardiac disease. The accumulation patterns were classified as either none, diffuse, focal or focal on diffuse. When a focal uptake was only observed on the basal wall, then the patterns were classified as having either a ring, over half or spot uptake. Results: The frequencies of the myocardial FDG uptake patterns were as follows: none, n=52 (27.7%); diffuse, n=63 (33.5%); focal on diffuse, n=40 (21.3%) and focal, n=33 (17.6%). The age, blood glucose level, weight and dose of FDG did not differ significantly for each pattern. The focal and focal on diffuse patterns were seen in 73 patients, and 65 patients had a focal uptake only on the basal wall; ring uptake in 29 patients, over half in 20 and spot uptake in 16 patients. Conclusions: The physiological myocardial uptake showed several patterns. Focal uptake was often seen in patients with cardiac disease, but it did not always indicate an abnormal finding when the accumulation was only on the basal wall.
(Keyword)
F-FDG PET / heart / physiological myocardial uptake / fasting state
Hitoshi Kubo, Masafumi Harada, Minoru Sakama, Tsuyoshi Matsuda and Hideki Otsuka : Preliminary observation of dynamic changes in alcohol concentration in the human brain with proton magnetic resonance spectroscopy on a 3T MR instrument, Magnetic Resonance in Medical Sciences, Vol.12, No.3, 235-240, 2013.
(Summary)
Purpose: Our purposes were to establish suitable conditions for proton magnetic resonance spectroscopy (MRS) to measure dynamic changes in alcohol concentration in the human brain, to evaluate these changes, and to compare the findings with data from analysis of breath vapor and blood samples. Materials and Methods: We evaluated 4 healthy volunteers (mean age 26.5 years; 3 males, one female) with no neurological findings. All studies were performed with 3-tesla clinical equipment using an 8-channel head coil. We applied our modified single-voxel point-resolved spectroscopy (PRESS) sequence. Continuous measurements of MRS, breath vapor, and blood samples were conducted before and after the subjects drank alcohol with a light meal. The obtained spectra were quantified by LCModel Ver. 6.1, and the accuracy of the MRS measurements was estimated using the estimated standard deviation expressed in percentage (%SD) as a criterion. Results: Alcohol peaks after drinking were clearly detected at 1.2 ppm for all durations of measurement. Good correlations between breath vapor or blood sample and MRS were found by sub-minute MRS measurement. The continuous measurement showed time-dependent changes in alcohol in the brain and various patterns that differed among subjects. Conclusions: The clinical 3T equipment enables direct evaluation of sub-minute changes in alcohol metabolism in the human brain.
Hiroaki Toba, Kazuya Kondo, Yohei Sadohara, Hideki Otsuka, Masami Morimoto, Koichiro Kajiura, Yasushi Nakagawa, Mitsuteru Yoshida, Yukikiyo Kawakami, Hiromitsu Takizawa, Koichiro Kenzaki, Shoji Sakiyama, Yoshimi Bando and Akira Tangoku : 18F-fluorodeoxyglucose positron emission tomography/computed tomography and the relationship between fluorodeoxyglucose uptake and the expression of hypoxia-inducible factor-1, glucose transporter-1 and vascular endothelial growth factor in thymic epithelial tumours., European Journal of Cardio-Thoracic Surgery, Vol.44, No.2, e105-e112, 2013.
(Summary)
OBJECTIVES: The objective of this study was to evaluate the usefulness of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and the relationships among the expressions of hypoxia-inducible factor-1 (HIF-1), glucose transporter-1 (Glut-1) and vascular endothelial growth factor (VEGF), histological type, other clinical factors and FDG uptake in thymic epithelial tumours. METHODS: Thirty-three patients who underwent FDG-PET/CT before treatment were reviewed. All types of tumours were reclassified into three subgroups: low-risk thymomas (types A, AB and B1), high-risk thymomas (types B2 and B3) and thymic carcinomas. Tumour contour, pattern of FDG uptake, tumour size and maximum standardized uptake value (SUVmax) were obtained. Expressions of HIF-1, Glut-1 and VEGF were analysed immunohistochemically, and these expressions were evaluated using grading scales. RESULTS: FDG uptake was visually recognized in all (100%) tumours. A homogeneous pattern of FDG uptake was increasingly observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas (P = 0.016). SUVmax for thymic carcinomas was significantly higher than that for thymomas (P = 0.008). With the optimal cut-off value of SUVmax of 5.6, the sensitivity, specificity and accuracy for diagnosing thymic carcinoma were 0.75, 0.80 and 0.79, respectively. Regarding the mean scoring of HIF-1, Glut-1 and VEGF, increasing trends were observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas. Tumour size revealed a significant correlation with SUVmax (r = 0.60, P < 0.001), and the expression of HIF-1 showed a moderate association, but the expression of Glut-1 showed no correlation with SUVmax. Regarding correlations between the expression of the three markers, there were moderate associations between HIF-1 and Glut-1, and HIF-1 and VEGF, and a significant correlation between Glut-1 and VEGF (r = 0.60, P < 0.001). In type B1 thymoma, HIF-1 and Glut-1 were partly expressed in non-neoplastic immature lymphocytes. CONCLUSIONS: FDG-PET/CT should be performed in patients with tumours in the anterior mediastinum because the pattern of FDG uptake and SUVmax are useful in the differential diagnosis of thymic epithelial tumours. Furthermore, the expressions of HIF-1, Glut-1 and VEGF might be associated with malignancy of thymic epithelial tumours. In contrast, FDG uptake might be dependent on tumour size rather than Glut-1 overexpression.
Hayato Nose, Hideki Otsuka, Youichi Otomi, Kaori Terazawa, Shoichiro Takao, Seiji Iwamoto and Masafumi Harada : Correlations between F-18 FDG PET/CT and pathological findings in soft tissue lesions., The Journal of Medical Investigation : JMI, Vol.60, No.3-4, 184-190, 2013.
(Summary)
Objective: To evaluate the correlations between F-18 FDG uptake imaged with PET/CT and pathological findings in soft tissue lesions. Methods: Fifty-four soft tissue lesions in 47 patients were evaluated. The correlations between the degree of FDG uptake, pathological type and grade, and MRI signal intensity and/or enhancement pattern were evaluated. Tumor FDG uptake was quantified by the maximum standardized uptake value (SUVmax). Results: Thirty-one lesions were malignant and twenty-three lesions were benign. The difference between SUVmax in the malignant and benign groups was statistically significant (p<0.001). Malignant myxoid lesions and well differentiated liposarcoma showed low FDG uptake. Benign neurogenic lesions showed low FDG uptake while malignant neurogenic tumors showed high FDG uptake, and the difference between SUVmax in the benign and malignant lesions was statistically significant (p<0.001). In a neurofibromatosis type-1 patient who had multiple neurogenic tumors, FDG-PET/CT could distinguish malignant peripheral nerve sheath tumors from other benign lesions with similar MRI findings. Conclusions: FDG-PET/CT is useful for differentiating malignant from benign soft tissue lesions, but malignant soft tissue lesions may show various patterns on FDG-PET, and MRI may be helpful for a differential diagnosis. J. Med. Invest. 60: 184-190, August, 2013.
Ayumi Nose, Hideki Otsuka, Hayato Nose, Yoichi Otomi, Kaori Terazawa and Masafumi Harada : Visual and semi-quantitative assessment of brain tumors using (201)Tl-SPECT., The Journal of Medical Investigation : JMI, Vol.60, No.1-2, 121-126, 2013.
(Summary)
To evaluate the usefulness of (201)Tl-SPECT in differentiating benign from malignant brain tumors. Eighty-eight patients (44 males and 44 females) with 58 high-grade (WHO grade III-IV) and 30 low-grade (WHO grade I-II) tumors were evaluated with (201)Tl-SPECT. (1) Visual assessment was performed by board-certificated radiologists using (201)Tl-SPECT. Tumors were classified in two groups (Tl-positive and Tl-negative) and scored using the five grade evaluation system. Receiver operating characteristic (ROC) analysis was performed in the Tl-positive group. (2) Semi-quantitative assessment involved measurement of early and delayed (201)Tl uptake, and the retention index (RI) was applied as follows: RI=delayed uptake ratio/early uptake ratio. Three combinations of RI using mean and maximum values of the region of interest were calculated. (1) Seventy-four Tl-positive and 14 Tl-negative tumors. The area under the ROC curve (AUC) estimated by three radiologists exceeded a value of 0.7. The value was greater when estimated by the more experienced radiologist. (2) In all RIs, the difference of RI between high-grade tumors and low-grade tumors was statistically significant. A visual and semi-quantitative assessment using (201)Tl-SPECT was found to be useful for differentiating benign from malignant brain tumors.
Yoichi Otomi, Hideki Otsuka, Kaori Terazawa, Hayato Nose, Michiko Kubo, Kazuhide Yoneda, Kaoru Kitsukawa and Masafumi Harada : (18)F-2-fluoro-2-deoxyglucose uptake in or adjacent to blood vessel walls., The Journal of Medical Investigation : JMI, Vol.60, No.1-2, 15-20, 2013.
(Summary)
Incidental (18)F-2-fluoro-2-deoxyglucose (FDG) uptake in blood vessel walls is sometimes demonstrated during routine oncologic imaging with positron emission tomography/computed tomography (PET/CT). FDG uptake in vessel walls can also be seen under some non-physiological conditions such as vasculitis and arteriosclerosis. Radiologists need to be aware of the diseases which can exhibit FDG uptake in the vessel wall for proper interpretation.
Hideki Otsuka : The utility of FDG-PET in the diagnosis of thymic epithelial tumors., The Journal of Medical Investigation : JMI, Vol.59, No.3-4, 225-234, 2012.
(Summary)
In this article, seven studies evaluating the utility of FDG-PET in the diagnosis of thymic epithelial tumors were reviewed and the results of an investigation conducted in Tokushima University Hospital are reported. FDG accumulation of low-risk thymoma is low, and FDG accumulation of thymic carcinoma is high. High-risk thymoma exhibits various degrees of accumulation and a definite conclusion has not yet been reached; however, overall, the higher the histological grade, the higher the FDG accumulation becomes, suggesting that this is correlated to staging. Our data also support the previous reports. FDG-PET may indicate lymph node metastasis and distant metastasis, which are sometimes difficult to detect using other modalities. When lymph node metastasis and/or distant metastasis are suspected in addition to thymic lesions, FDG-PET/CT, which allows for searching of the entire body at once, is useful. FDG-PET/CT is effective for estimating histopathological malignancy and staging in the diagnosis of thymic epithelial tumors and can be an important imaging test with high relevance to the prognosis of a patient.
Youichi Otomi, Hideki Otsuka, Naomi Morita, Kaori Terazawa, Kaori Furutani, Masafumi Harada and Hiromu Nishitani : Relationship between FDG uptake and the pathological risk category in gastrointestinal stromal tumors., The Journal of Medical Investigation : JMI, Vol.57, No.3-4, 270-274, 2010.
(Summary)
To evaluate (18)F-fluorodeoxyglucose (FDG) uptake and the pathological risk category of gastrointestinal stromal tumors (GISTs), and to investigate the possibility of determining the pathological risk category by positron emission tomography/computed tomography (PET/CT). Patients and We undertook 29 PET/CT studies in 20 patients with GISTs. Eleven of the 20 patients underwent PET/CT prior to therapy, with three of these also undergoing follow-up PET/CT after operation or imatinib therapy. All eleven lesions imaged before treatment were FDG-positive on PET/CT. Seven of these eleven primary lesions were categorized as high risk and the other four primary lesions were categorized as low or intermediate risk. There was a significant difference between the maximum standardized uptake value (SUVmax) of the primary lesions categorized as high risk (11.8±3.15) and that of the primary lesions categorized as low and intermediate risk (2.88±0.47) (p<0.001). Recurrent tumors were also shown as FDG-positive. Primary GISTs and recurrent tumors can be detected by PET/CT. Our study suggests that the degree of FDG uptake is a useful indicator of risk category. In addition, PET/CT is probably useful for follow-up examinations of GIST after operation or imatinib therapy. J. Med. Invest. 57: 270-274, August, 2010.
Hiroaki Toba, Kazuya Kondo, Hideki Otsuka, Hiromitsu Takizawa, Koichiro Kenzaki, Shoji Sakiyama and Akira Tangoku : Diagnosis of the presence of lymph node metastasis and decision of operative indication using fluorodeoxyglucose-positron emission tomography and computed tomography in patients with primary lung cancer., The Journal of Medical Investigation : JMI, Vol.57, No.3-4, 305-313, 2010.
(Summary)
PET/CT is superior to CT scan in lymph node staging. However, because the false-positive rate is high in PET-positive lymph nodes measuring less than 1 cm in diameter, we think that clinical background should be considered and other modalities or histological examinations should be undertaken if necessary. J. Med. Invest. 57: 305-313, August, 2010.
Masafumi Harada, Hitoshi Kubo, Takamasa Abe, Hiroshi Maezawa and Hideki Otsuka : Selection of endogenous 13C substrates for observation of intracellilar metabolism using the dynamic nuclear polarization technique, Japanese Journal of Radiology, Vol.28, No.2, 173-179, 2010.
(Summary)
The aim of this study was to select a suitable substrate candidate for dynamic nuclear polarization (DNP) studies and demonstrate its utility for evaluating intracellular metabolism. Hyperpolarized substances included 1-(13)C-pyruvate (Pyr), 1-(13)C-glucose (Glc), and 1-(13)C-acetate. A DNP polarizer and a 600-MHz vertical small-bore scanner were used for (13)C-MR spectroscopic measurements. After polarization for 1 h, the dissolved solution was injected via a capillary line into the nuclear magnetic resonance tube in the scanner. The sequential spectra of the hyperpolarized (13)C-labeled substrates were acquired in durations of more than 120 s, and a thermal spectrum was obtained more than 1 h thereafter. FM3A cancer cells of mammary tumors were cultured for intracellular detection of the hyperpolarized (13)C-substances. The greatest sensitivity was found using Pyr with the longest T1 decay (51.5 s); and remarkably, the least sensitivity was observed using Glc with a signal decay of less than 2 s. An effective increase in sensitivity was shown using the other substances. The hyperpolarized intracellular study using (13)C-Pyr showed distinct elevation of lactate levels. The DNP technique is useful for evaluating intracellular metabolism. However, Glc is not suitable for use with the DNP technique.
Kaori Terazawa, Hideki Otsuka, Youichi Otomi, Naomi Morita, Shoichiro Takao, Seiji Iwamoto, Kyosuke Osaki, Masafumi Harada and Hiromu Nishitani : How to manage RI venography in pre-orthopedic surgery patients, Annals of Nuclear Medicine, Vol.24, No.2, 107-113, 2010.
(Summary)
The preoperative evaluation of venous thromboembolism (VTE) is important to avoid complications, because VTE is often induced by orthopedic surgery. We focused on radioisotope venography (RIV) using 99mTc-macroaggregated human serum albumin, examining orthopedic patients. We conducted 34 examinations in 33 patients who were referred for RIV and lung perfusion scintigraphy for the pre-orthopedic operative evaluation of VTE. Two board-certified (one nuclear medicine board-certified) radiologists interpreted the images based on the following: (1) flow defect of the lower extremities; (2) interruption of flow; (3) irregular or asymmetric filling of the deep vein (low flow); (4) presence of collateral vessels; and (5) abnormal RI retention on delayed-phase images. Scoring was based on a 5-point scale, and more than 2 points was considered VTE positive. Abnormal findings were noted in 27 of the 34 examinations performed in the 33 patients and normal findings in the other 7 examinations. According to the RI score, 21 patients were classified into the VTE-positive group and 12 into the VTE-negative group. Surgery was canceled because of advanced age and respiratory dysfunction in 2 of the 21 patients in the VTE-positive group. Of the 19 patients who underwent surgery, an IVH filter was placed before surgery in 2 and anticoagulant treatment with heparin and warfarin was initiated on the day of surgery in 12 to prevent postoperative VTE, and only one of the patients receiving anticoagulant treatment developed PTE after surgery. Surgery was canceled due to advanced age and at patient's request in 2 of 12 patients in the VTE-negative group. Anticoagulant treatment with heparin/ warfarin was performed to prevent postoperative VTE in only 3 patients: one with a past medical history of pulmonary infarction, one with atrial fibrillation, and one suspected of having antiphospholipid antibody syndrome. No patient in the VTE-negative group developed VTE after surgery. The preoperative identification of patients with VTE by RIV might be useful for perioperative management and the evaluation of preventive measures against postoperative VTE.
(Keyword)
Adult / Aged / Aged, 80 and over / Female / Humans / Male / Middle Aged / Organotechnetium Compounds / Orthopedics / Phlebography / Radioisotopes / Serum Albumin / Venous Thromboembolism
Hideki Otsuka, Kaori Terazawa, Naomi Morita, Yoichi Otomi, Shoichiro Takao, Seiji Iwamoto, Kyosuke Osaki, Masafumi Harada and Hiromu Nishitani : Thallium-201 chloride scintigraphy in soft tissue tumors., The Journal of Medical Investigation : JMI, Vol.56, No.3-4, 136-141, 2009.
(Summary)
We report the findings of Thallium-201 chloride ((201)TlCl) scintigraphy and consider how to use this technique to evaluate the character of soft tissue lesions. We enrolled 91 consecutive patients (45 males and 46 females, age range 8-91-years-old). Nineteen patients were malignant and 72 were benign. Patients were scanned 15 minutes (early phase) and 3 hours (delayed phase) after (201)TlCl injection. More intense uptake in the lesion compared to the normal side was considered as 'high', the same degree of uptake was considered 'iso', and decreased uptake was 'low'. The retention index (RI) was calculated in 9 patients in the malignant group and in 16 patients in the benign group. In malignant tumors, 15 of 19 patients showed high uptake in both the early and delayed phases. One malignant fibrous histiocytoma patient was high only in the delayed phase and 1 liposarcoma patient was high only in the early phase. Two liposarcoma patients showed an iso uptake in both phases. One of these patients was pathologically diagnosed as a myxoid type. In benign lesions, no lipoma showed increased uptake. All neurogenic tumors except for 2 demonstrated high uptake. All 3 ganglions of the lower extremities showed iso uptake. Most inflammatory diseases showed increased uptake. Clinically-considered benign patients consisted of tumorous lesions or inflammatory disease. Only 2 patients were considered 'low', and these were diagnosed as intramuscular hematoma and cyst. RI was variable in both malignant and benign lesions and no statistically significant difference was seen between malignant and benign lesions by t-test (p=0.72). A high (201)TlCl uptake lesion is more frequently seen in malignant tumors, but regardless of whether the tumor is benign or malignant, according to the histopathological variety, the (201)TlCl uptake pattern can not be the only indicator to differentiate malignant from benign tumors. We ultimately need to evaluate the nature of tumors by a combination of several imaging techniques.
(Keyword)
Adolescent / Adult / Aged / Aged, 80 and over / children / Diagnosis, Differential / Female / Histiocytoma, Malignant Fibrous / Humans / Liposarcoma / magnetic resonance imaging / Male / Middle Aged / Radiopharmaceuticals / Soft Tissue Neoplasms / Thallium / Thallium Radioisotopes / Young Adult
Naomi Morita, Hideki Otsuka, Kyo Yamashita and Hiromu Nishitani : Comparison with Bone Scintigraphy and MDCT Findings in Patients with Round Focal Accumulation on Bone Scintigraphy, Japanese Journal of Nuclear Medicine, Vol.46, No.1, 13-20, 2009.
(Keyword)
Bone scintigraphy / MDCT / Round focal accumulation
Hideki Otsuka, Kaori Terazawa, Naomi Morita, Yoichi Otomi, Kyo Yamashita and Hiromu Nishitani : Is FDG-PET/CT useful for managing malignant pleural mesothelioma?, The Journal of Medical Investigation : JMI, Vol.56, No.1-2, 16-20, 2009.
(Summary)
Imaging techniques such as CT, MRI and PET/CT have essential pre- and post-treatment roles in detecting tumors and evaluating the extension of malignant pleural mesothelioma (MPM). We sough to evaluate the advantages and limitations on FDG-PET/CT findings. We performed 13 FDG-PET/CT studies in 9 patients with MPM (8 males, 1 female, aged 51 to 84 years, 9 at the initial diagnosis, 4 follow up studies). We reviewed FDG-PET/CT findings of primary tumors, recurrent tumors, lymph nodes, metastasis. All primary and recurrent tumors were FDG positive. The uptake patterns at initial diagnosis were; diffuse+multi-nodular uptake pattern in 5, diffuse irregular thickened uptake pattern in 2, some focal thickened pattern in one, and a slight diffuse uptake pattern in one. Two of the 3 patients diagnosed as N0 by PET and operated on had negative lymph nodes confirmed pathologically. The other patient diagnosed as N0 by PET, who had one month of time lag between PET/CT examination and surgery, was confirmed as N2 by extrapleural pneumonectomy. In 3 patients, hilar or mediastinal lymph nodes were difficult to distinguish from irregular pleural thickening. One patient had a FDG positive lymph node in the ipsilateral supraclavicular region confirmed as metastasis (N3). One patient had a FDG positive lymph node in the para-aortic region. Lung metastasis was seen in one patient (M1). In another patient, two focal nodular uptakes in the colon were detected and confirmed as colon polyps (pathologically Group 3-4). At restaging, 3 of 4 patients showed diffuse+multi-nodular uptake and one patient showed multi-nodular uptake. The utility of FDG-PET/CT is limited for evaluation of primary tumor extension and nodal status. FDG-PET/CT is useful for detecting distant metastasis and for evaluating activity in supraclavicular or abdominal lymph nodes. It is also useful for identifying unsuspected diseases.
Kaori Terazawa, Hideki Otsuka, Naomi Morita, Kyo Yamashita and Hiromu Nishitani : Clear-cell sarcoma of the small intestine detected by FDG-PET/CT during comprehensive examination of an inflammatory reaction., The Journal of Medical Investigation : JMI, Vol.56, No.1-2, 70-75, 2009.
(Summary)
Clear-cell sarcoma (CCS) is a rare, malignant, soft-tissue tumor, which involves the extremities, particularly the foot and foot joint tendons and aponeuroses. It is morphologically similar to but histochemically distinct from malignant melanoma. CCS arising in the gastrointestinal tract has rarely been reported. The prognosis of CCS is reportedly poor because of the high incidence of metastases at the time of initial diagnosis and the high frequency of recurrence. We report a case of early-stage CCS of the small intestine detected by (18)F-fluoro-2-deoxy D-glucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) during the comprehensive examination of an inflammatory reaction. In this case, FDG-PET/CT clearly visualized the lesion, which was difficult to detect by contrast CT.
Yoichi Otomi, Hideki Otsuka, Naomi Morita, Kaori Terazawa, Masafumi Harada and Hiromu Nishitani : A case of von Recklinghausen's disease with coincident malignant peripheral nerve sheath tumor and gastrointestinal stromal tumor., The Journal of Medical Investigation : JMI, Vol.56, No.1-2, 76-79, 2009.
(Summary)
(18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET/CT) was performed to evaluate a left femoral subcutaneous mass in a patient with von Recklinghausen's disease (vRd) that gradually enlarged, causing pain and numbness. The left femoral mass showed intense FDG uptake with the maximum standardized uptake value (SUVmax) of 9.0. Other subcutaneous masses considered benign and neurogenic in nature also showed FDG uptake (SUVmax around 3 or less), but the degree of FDG uptake differed considerably from the left femoral mass. This observation suggested that the degree of FDG uptake may be a useful indicator of malignant transformation. Incidentally, PET/CT also showed an asymptomatic large abdominal mass with intense FDG uptake (SUVmax 8.8). The abdominal mass was resected and confirmed as gastrointestinal stromal tumor (GIST) of the small intestine. Three months later, the left femoral mass was operated on and pathologically diagnosed as a malignant peripheral nerve sheath tumor (MPNST). Various malignant diseases are known to occur with high frequency in vRd. Therefore, vRd patients need to have periodical examinations including PET/CT. We present a rare case of a patient with vRd with a MPNST of the left femur and coincidental GIST of the small intestine. February, 2009.
Tetsuya Tsujikawa, Hideki Otsuka, Naomi Morita and Hiromu Nishitani : Does partial volume corrected maximum SUV based on count recovery coefficient in 3D-PET/CT correlate with clinical aggressiveness of non-Hodgkins lymphoma?, Annals of Nuclear Medicine, Vol.22, No.1, 23-30, 2008.
(Summary)
There is much controversy about the correlation between the degree of 2-[(18)F]fluoro-2-deoxy-D: -glucose (FDG) uptake and clinical aggressiveness of non-Hodgkin's lymphoma (NHL). In this study, we investigated whether partial volume corrected FDG uptake based on count recovery coefficient in 3D-positron emission tomography (PET)/computed tomography (CT) correlates with the clinical aggressiveness of NHL and improves diagnostic accuracy. Forty-two patients with NHL underwent FDG-PET/CT scans (26 aggressive NHLs and 16 indolent ones). Count recovery curve was obtained using NEMA 2001 body phantom. Scan protocol and reconstructive parameters in the phantom study were the same as those in a clinical scan except for emission time. Relative recovery coefficient (RC) was calculated as RC = A/B (A, maximum pixel count of each hot sphere; B, maximum pixel count of greatest sphere). Partial volume corrected maximum count of standardized uptake value (PVC-SUV) was calculated as PVC-SUV = NC-SUV/RC (NC-SUV: non-corrected maximum count of SUV). Three parameters (NC-SUV, PVC-SUV, and size) between aggressive and indolent NHLs were compared. Significant differences were shown in all parameters between aggressive and indolent NHLs. Means +/- SD of NC-SUV, PVC-SUV, and size was as following: NC-SUV (15.3 +/- 6.9, 8.7 +/- 7.0; P < 0.01), PVC-SUV (18.2 +/- 8.1, 12.7 +/- 7.8; P < 0.05), and size (mm, 32.4 +/- 18.3, 21.9 +/- 10.3; P < 0.05). When an NC-SUV of 9.5 was the cutoff for aggressive NHL, the receiver-operating-characteristic (ROC) analysis correctly identified 21 of 26 aggressive ones. Sensitivity and specificity were 81% each, and the positive and negative predictive values were 88% and 72%, respectively. When a PVCSUV of 11.2 was the cutoff, the ROC analysis revealed 81% sensitivity, 63% specificity, and positive and negative predictive values of 78% and 67%, respectively. At a cutoff for aggressive NHL of a size of 27 mm, the ROC analysis revealed 50% sensitivity, 81% specificity, and positive and negative predictive values of 81% and 50%, respectively. The comparison of area under the curve in ROC analyses indicated that NC-SUV showed the greatest diagnostic accuracy (NC-SUV 0.84, PVC-SUV 0.72, and size 0.69). Diagnostic accuracy of PVC-SUV was inferior to that of NC-SUV. These results suggest that NC-SUV, which contains information on both size and FDG density, provides better differentiation between aggressive and indolent NHLs than PVC-SUV.
Hideki Otsuka, Naomi Morita, Kyo Yamashita and Hiromu Nishitani : FDG-PET/CT findings of autoimmune pancreatitis associated with idiopathic retroperitoneal fibrosis, Annals of Nuclear Medicine, Vol.21, No.10, 593-596, 2007.
(Summary)
We report the fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) findings of autoimmune pancreatitis (AIP) associated with idiopathic retroperitoneal fibrosis. A 69-year-old male patient was admitted to our hospital with obstructive jaundice. Six months prior to this admission, he was treated with steroid therapy for retroperitoneal fibrosis. Laboratory data showed that elevated T-bil, C-reactive protein, amylase and immunoglobulin 4, and antinuclear antibodies were positive. Clinical history, laboratory data, CT image, and magnetic resonance imaging led to a diagnosis of autoimmune pancreatitis. To investigate the inflammatory activity, FDG-PET/CT was undertaken. FDG-PET/CT demonstrated diffuse intense FDG uptake in the enlarged pancreas and diffuse mild uptake in the region of the abdominal aorta-bilateral iliac arteries. A dilated right renal pelvis and upper ureter, corresponding to hydronephrosis probably caused by retroperitoneal fibrosis, were shown. An FDG-PET/CT was useful to evaluate inflammatory activity and morphological imaging, and supported our diagnosis of AIP and retroperitoneal fibrosis.
Kazuhide Yoneda, Junji Ueno, Sadamitsu Nishihara, Tetsuya Tsujikawa, Naomi Morita, Hideki Otsuka, Kaori Furutani, Hiromu Nishitani, Kazuya Kondo and Yasuhiko Nishioka : Postprocessing technique with MDCT data improves the accuracy of the detection of lung nodules, Radiation Medicine, Vol.25, No.10, 511-515, 2007.
(Summary)
The aim of this study was to determine whether postprocessing techniques could improve the accuracy of detecting lung nodules. A total of 154 segmented lung volumes of multidetector-row computed tomography (MDCT) data were the subject of the study. Lung nodules were present in 88 volumes and absent in 66 volumes. We prepared four groups: (1) 7- or 10-mm thick-section axial images; (2) 1-mm thin-section axial images; (3) sliding slab maximum intensity projection (MIP) images with a slab thickness of 15 mm; and (4) sliding slab volume rendering (VR) images with a slab thickness of 15 mm. Sixteen physicians reviewed each group in interactive cine mode. The observers' performance in the detection of lung nodule was evaluated by receiver operating characteristic (ROC) analysis. The observers' performance of the MIP and VR groups was significantly better than in other two groups. There was no significant difference statistically between the thin and thick groups. The detectability of lung nodules is improved with the use of sliding slab MIP and VR using thin-section image data. Thin-section volume data are essential for improving diagnostic accuracy, but observation of thin-section images without utilization of image-processing techniques dose not improve diagnostic accuracy.
Naomi Morita, Hideki Otsuka, Kyo Yamashita and Hiromu Nishitani : Utility of FDG-PET/CT examination for patients with cancer of unknown origin., Shikoku Acta Medica, Vol.63, No.3-4, 121-126, 2007.
(Summary)
We reported the utility of18F-FDG-PET/CT examination for patients with cancer of unknownprimary origin. Twenty six patients(13 men, 13 women, aged 27-91 years, mean 71)were examined.The indication for PET/CT examination was tumor maker elevation(14 patients), suspectedmetastatic tumor(14)and metastasis diagnosed histopathologically(3). Patients weretold not to eat for at least four hours and a PET/CT image was obtained one hour after theadministration of 3.7MBq/kg FDG. From April to August 2006, 33 patients diagnosed with a cancerof unknown primary origin were referred to our hospital for PET/CT examination from anoutside institution. Twenty six patients could be investigated for outcomes. Seventeen patientsshowed an abnormal accumulation, with 14 of the 17 having their primary regions detected histopathologicallyor clinically. For one patient, the abnormal accumulation could not be determined toshow the origin. For 2 patients, it was difficult to diagnose if these abnormal accumulationsshowed the primary region or not, but CT examinations were helpful for a diagnosis. Seven of the9 patients who showed no abnormal accumulation were treated conservatively and the primaryregion for their cancer could not be detected during the follow up study. In 21 of 26 patients, theseresults were useful to select an appropriate therapy to be applied or a relevant examination. Weconsidered PET/CT examination, where it is possible to scan the whole body at one time, was veryuseful to get both morphologic and metabolic information. PET/CT examination showed a highersensitivity for detecting abnormal lesions than other imaging modalities.
Hideki Otsuka, Naomi Morita, Kyo Yamashita and Hiromu Nishitani : FDG-PET/CT for diagnosis and follow-up o f vasculitis., The Journal of Medical Investigation : JMI, Vol.54, No.3-4, 345-348, 2007.
(Summary)
We report three cases of vasculitis evaluated by FDG-PET/CT. Vasculitis is defined as inflammatory changes and necrosis in the aterial wall. The patients presented with non-specific symptoms such as fever up or elevated inflammatory markers. FDG-PET/CT clearly demonstrated intense FDG uptake in vessel walls. A 72-year-old female patient with a one month history of pyrexia had abnormal laboratory data suggesting an inflammatory process. FDG-PET/CT was very useful for the diagnosis of vasculitis. Steroid therapy was introduced. Normalization of laboratory data and symptomatic improvement correlated with normalization of FDG uptake in the vessels.
Hideki Otsuka, Naomi Morita, Kyo Yamashita and Hiromu Nishitani : FDG-PET/CT for cancer management, The Journal of Medical Investigation : JMI, Vol.54, No.3-4, 195-199, 2007.
(Summary)
FDG-PET/CT is increasingly being used for staging, restaging, and treatment monitoring for cancer patients. The introduction of a PET/CT system enables both morphological and metabolic imaging to be performed in a single session. Knowledge of the normal physiologic distribution of FDG and an understanding of the clinical indications and limitations of PET/CT enable accurate diagnosis and thus a better level of care for patients.
Hideki Otsuka, Graham M Michael, Kogame Masahiro and Hiromu Nishitani : The impact of FDG-PET in the management of patients with salivary gland malignancy, Annals of Nuclear Medicine, Vol.19, No.8, 691-694, 2005.
(Summary)
The aim of this study was to evaluate the impact of FDG-PET in the management of patients with salivary gland malignancy. We performed 45 FDG PET studies in 31 patients with salivary malignant tumors, using PET (33 studies) and PET/CT (12 studies). Patients comprised 21 males and 10 females with a mean age of 69 y (range 38-89). Nineteen patients had a single study, ten patients had 2 and two patients had 3 studies. Twelve studies were performed for initial staging and 33 studies for restaging. Four patients of the initial staging group were restaged with PET after therapy. Histology consisted of 8 adenocarcinomas, 8 squamous cell carcinomas, 4 adenoid cystic carcinomas, 4 carcinoma ex pleomorphic adenomas, 2 mucoepidermoid carcinomas, 2 poorly differentiated carcinomas, 1 salivary duct carcinoma, 1 lymphoepithelial carcinoma and 1 melanoma. PET findings were reviewed with the clinical and radiologic findings and the impact of PET on staging and patient management was determined. In the initial staging group, all 12 primary lesions (100%) showed positive FDG uptake (5 squamous cell carcinomas, 2 adenocarcinomas, 2 poorly differentiated carcinomas, 1 carcinoma ex pleomorphic adenoma, 1 salivary duct carcinoma, 1 lymphoepithelial carcinoma). Three patients (25%) had FDG positive distant disease (liver, bone, lymph nodes); surgery was canceled and therapy changed to chemoradiation. One patient (9%) with no FDG uptake in the neck nodes avoided a planned neck dissection. In the restaging group (33 studies in 23 patients), 5 patients (22%) had FDG positive distant disease, which changed the treatment from surgery to chemoradiation or other. A second primary lesion was detected in one patient (4%). One patient (4%) with clinically suspected recurrence was able to avoid other invasive procedures because of the negative PET. Overall, FDG PET resulted in a major change in management in 11 of 31 patients (35%). This study shows that FDG PET has a significant impact on the management of patients with salivary malignant tumors in both the initial staging and restaging.
(Keyword)
Adult / Aged / Aged, 80 and over / Female / Fluorodeoxyglucose F18 / Humans / Male / Middle Aged / Neoplasm Staging / Positron-Emission Tomography / Prognosis / Radiopharmaceuticals / Reproducibility of Results / Salivary Gland Neoplasms / Sensitivity and Specificity
Hideki Otsuka, Graham M. Michael, Akiko Kubo and Hiromu Nishitani : The effect of oral contrast on large bowel activity in FDG-PET/CT., Annals of Nuclear Medicine, Vol.19, No.2, 101-108, 2005.
(Summary)
The purpose of this study was to determine the effect of oral contrast on FDG uptake in the colon and to determine the normal distribution of FDG in the colon. Sixty patients (30 patients in no contrast group and 30 patients in the received contrast group) underwent FDG-PET/ CT scans. The pattern of FDG uptake was classified into 5 patterns (diffuse, segmental, single-nodular, multi-nodular, and other) in 5 segments (ascending, transverse, descending, and rectosigmoid colon). SUVs of the no oral contrast group were examined. The ratios of FDG uptake patterns were compared in the received contrast group and no contrast group to evaluate the effect of oral contast. The effect of attenuation correction on the uptake pattern was evaluated by comparison of the attenuation-corrected and non-attenuation-corrected PET images. In the no contrast group, there was no significant uptake in 72 segments (59%) and a diffuse pattern was seen in 29 segments (24%), most frequently in the ascending colon and descending colon. A segmental pattern was seen in 15 segments (13%), most frequently in the rectosigmoid colon. A single-nodular pattern was seen in 3 segments (3%) and multi-nodular pattern in 1 segment (1%). A nodular pattern was seen only in the ascending colon. SUVmax of the ascending colon and that of the rectosigmoid colon were significantly higher than those of the transverse and descending colon. The frequencies of diffuse, multi-nodular and 'other' patterns were significantly higher in the received contrast group than in no contrast group. There was no significant difference between the frequency of the segmental pattern or the single nodular pattern in the two groups. There was no significant difference between the uptake patterns with attenuation correction and those without attenuation correction in either the received contrast group or no contrast group. Normal FDG uptake in the large bowel may show various degrees and patterns of uptake among the colonic segments. Oral contrast agent can cause focal or diffuse increased FDG uptake, which may be induced not only by the high CT density of oral contrast but also by an accelerated physiologic reaction of the large bowel.
(Keyword)
Administration, Oral / Adolescent / Adult / Aged / Aged, 80 and over / Artifacts / Contrast Media / Female / Fluorodeoxyglucose F18 / Humans / Intestine, Large / Male / Metabolic Clearance Rate / Middle Aged / Positron-Emission Tomography / Radiopharmaceuticals / Reproducibility of Results / Retrospective Studies / Sensitivity and Specificity / Tissue Distribution / Tomography, X-Ray Computed
(Link to Search Site for Scientific Articles)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 15909489
Naomi Morita, Kashihara Kenichi, Tagashira Hiroshi, Hideki Otsuka, Yoneda Kazuhide, Murase Tomoya, Tsujikawa Tetsuya, Furutani Shunsuke, Furutani Kaori, Minato Masako and Hiromu Nishitani : Two cases of retroperitoneal hematoma caused by combination of anticoagulant therapy and 5-fluorouracil, The Journal of Medical Investigation : JMI, Vol.52, No.1,2, 114-117, 2005.
(Summary)
We reported two cases of retroperitoneal hematoma in patients who received a combination of anticoagulant therapy and 5-fluorouracil (5-FU). We should be aware of the possible interaction of this combination therapy and monitor prothrombin time (PT) prolongation. CT is useful for evaluation of the disease.
(Keyword)
Aged / Anticoagulants / Antimetabolites, Antineoplastic / Colonic Neoplasms / Drug Interactions / Esophageal Neoplasms / Fluorouracil / Hematoma / Humans / Male / Retroperitoneal Space
Hideki Otsuka, Graham M Michael, Kubo Akiko and Hiromu Nishitani : FDG-PET/CT findings of sarcomatous transformation in neurofibromatosis: a case report, Annals of Nuclear Medicine, Vol.19, No.1, 55-58, 2005.
(Summary)
We herein report FDG-PET/CT findings of sarcomatous transformation in a patient with neurofibromatosis type 1 (NF-1). About 5% of patients with NF-1 develop sarcomatous transformation of a malignant peripheral nerve sheath tumor which arises from plexiform neurofibromas and is often associated with a poor prognosis. Morphologic imaging techniques such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) are the standard methods to define the anatomic extent of the tumor, although tumor heterogeneity prevents reliable differentiation between benign and malignant lesions. The degree of fluoro-deoxyglucose (FDG) uptake correlates with histologic grade in neurogenic tumors in NF-1 patients. Our patient had a huge mass in the left gluteus area with a large nearly circular focus of increased FDG uptake in the tumor. The mass had a photopenic center. The maximum Standard Uptake Value (SUVmax) of this mass was 6.6. There was CT evidence of invasion of the left iliac wing, left acetabulum, and left superior pubic ramus; however there was no increased FDG uptake in these areas on the PET study. We surmised that the high FDG uptake indicated a high grade sarcoma, which was confirmed histologically. There was also a focal region of increased uptake in the L5 vertebral body, correlating with the CT hypodense lesion, with 2.9 SUVmax. FDG-PET/CT can identify sarcomatous change from benign neurogenic tumor with minimal misregistration, and can also detect metastatic disease. This case illustrates the importance of evaluating both metabolic and morphologic abnormalities to be able to formulate a proper treatment plan. This information can be obtained in a single session, using PET/CT.
Hideki Otsuka, Akiko Kubo, Graham Michael and Hiromu Nishitani : The relationship between standard uptake value (SUV) and Hounsfield Unit (HU) of oral contrast agent for FDG-PET/CT study., The Journal of Medical Investigation : JMI, Vol.51, No.3-4, 226-229, 2004.
(Summary)
The aim of this study was to examine the relationship between CT density (Hounsfield Unit, HU) and the degree of fluoro-deoxyglucose (FDG) uptake, demonstrated as standard uptake value (SUV). Twenty contiguous patients (9 males, 11 females, age range of 29-79) were performed FDG-PET/CT scan with 750ml of 5% iodine-based oral contrast agent. A region of interest (ROI) was placed manually on oral contrast in the lumen of stomach, small bowel and ascending colon, avoiding contamination of other structures, and the average SUV and average HU were determined. R square and p value were applied to evaluate the correlation. The correlation between SUV and HU in each separate location is not significant. When all regions are combined, p value is significant (<0.05), but R square is not significant. Oral contrast can be one factor that influences measured FDG, and it is possible it acts as an irritant that increases metabolism in the bowel wall, resulting in increased FDG uptake.
Hideki Otsuka, Masashi Hieda, Hiroyuki Shinbata, Akiko Kubo and Hiromu Nishitani : Comparison of washout rate between planar image and polar map image: 123I-BMIPP study., The Journal of Medical Investigation : JMI, Vol.50, No.3-4, 176-179, 2003.
(Summary)
Myocardial cells obtain 60-90% of their energy from free fatty acids under aerobic conditions. 123I-BMIPP can demonstrate fatty acid metabolism in the myocardium and is used to evaluate cardiac diseases. Forty-three patients underwent BMIPP imaging in the early (15 min) and delayed (4 hr) phase, and the washout rate was calculated. We evaluate the washout rate by two methods, the polar map method and the planar image method. The two methods showed close correlation (r=0.473).
(Tokushima University Institutional Repository: 110698, PubMed: 13678387)
67.
Masafumi Harada, H. Miyosh, Hideki Otsuka, Hiromu Nishitani and M. Uno : Multivariate analysis of regional metabolic differences in normal ageing on localised quantitative proton MR spectroscopy, Neuroradiology, Vol.43, No.6, 448-452, 2001.
Hideki Otsuka, Masafumi Harada, K Mori, S Hisaoka and Hiromu Nishitani : Brain metabolites in the hippocampus-amygdala region and cerebellum in autism: an 1H-MR spectroscopy study., Neuroradiology, Vol.41, No.7, 517-519, 1999.
(Summary)
Histological abnormalities of the brain in autism have been investigated extensively. We studied metabolites in the hippocampus-amygdala (HA) region and cerebellum. We examined the right HA region and left cerebellar hemisphere of 27 autistic patients 2-18 years old, 21 boys and 6 girls and 10 normal children 6-14 years old, 4 boys and 6 girls, using the STEAM sequence. This sequence was used to minimise the influence of relaxation times. The N-acetyl aspartate (NAA) concentration was significantly lower (P = 0.042) in autistic patients than in normal children (9.37 and 10.95 mM, respectively). There was no significant difference in other metabolites. The correlation coefficient (r value) of NAA between the HA region and cerebellum was 0.616. The decreased NAA concentration may be due to neuronal hypofunction or immature neurons. The NAA concentration in the HA region and cerebellum may be related, because of neuronal circuits or networks.
Hideki Otsuka, Masafumi Harada, K Koga and Hiromu Nishitani : Effects of hepatic impairment on the metabolism of fructose and 5-fluorouracil, as studied in fatty liver models using in vivo 31P-MRS and 19F-MRS., Magnetic Resonance Imaging, Vol.17, No.2, 283-290, 1999.
(Summary)
The purpose of this study was to observe the effects of hepatic impairment on the metabolism of fructose and 5-fluorouracil (5-FU) in fatty liver models using in vivo 31P-MRS and 19F-MRS and to compare the results. In addition, we compared the results to those of other conventional tests such as laboratory examinations, imaging and pathology. Male SIc:Wistar rats were examined on BEM170/200 (4.7 T, Otsuka Electronics, USA) with 17-mm diameter surface coil. Fatty liver was induced by a choline deficient diet (CD diet) for 2 weeks. 31P-MRS were obtained for 90 min after intravenous (i.v.) injection of 1 g/kg of fructose and 19F-MRS were measured for 100 min after i.v. injection of 100 mg/kg of 5-FU. 1H-MRS and 1H-MRI were also performed. On 31P-MRS, there was no statistical difference in the time course of phosphomonoester (PME), adenosine triphosphate (ATP), and inorganic phosphate (Pi) between CD diet group and control group. On 19F-MRS, we detected high peak of fluoronucleotide (Fnct) and suppressed peak of alpha-fluoro-beta-alanine (FBAL) in CD diet group. We showed the metabolism of fructose and 5-FU by 31P-MRS and 19F-MRS, respectively. There was no difference in fructose metabolism but we observed increased fluoronucleotide and decreased a-fluoro-b-alanine in 5-FU metabolism of fatty liver. We speculate that the effects of hepatic impairment in fatty liver may be more severe on 5-FU metabolism and the increased fluoronucleotide may reflect cell proliferation.
(Keyword)
Animals / Antimetabolites / Choline Deficiency / Fatty Liver / Fluorouracil / Fructose / Liver / nuclear magnetic resonance spectroscopy / Male / Rats / Rats, Wistar / Time Factors
Toshiharu Maeda, Nobuya Sano, Koui Togei, Masashi Shibata, Keisuke Izumi and Hideki Otsuka : Lack of carcinogenicity of phenytoin in (C57BL/6 x C3H)F1 mice, Journal of Toxicology and Environmental Health, Vol.24, No.1, 111-119, 1988.
(Summary)
Groups of 50 B6C3F1 mice of each sex were given 0.012% or 0.006% phenytoin in their powdered diet for 78 wk and were then fed a basal diet for 8 wk. Control groups of 50 mice of each sex were fed powdered basal diet for 86 wk. Mean total intakes of phenytoin per mouse were 301 and 150 mg in males, and 292 and 154 mg in females, respectively. The survival rates of each group at week 86 were 72-86% in males, and 86-94% in females. Liver-cell tumors, alveolar tumors, and Harderian-gland adenomas in male mice, malignant lymphomas and/or leukemias in female mice, and a few tumors in other organs of both sexes were found. The total number of hepatocellular tumors in mice treated with the high dose of phenytoin was significantly smaller than that of control mice in males (p less than 0.05). However, hepatocellular carcinomas developed 15 to 3 wk earlier in a few mice of phenytoin-treated males than in the controls. In other organs, no significant increase of any particular tumor type was observed in the treated groups of both sexes. Thus, phenytoin was not carcinogenic in B6C3F1 mice in this study.
(Keyword)
Administration, Oral / Animals / Body Weight / Carcinogens / Female / Liver Neoplasms / Male / Mice / Phenytoin / Sex Factors
The purpose of this study is to determine if combination of adequate postprocessing techniques and thin section image data from MDCT could improve the accuracy of detection of lung nodules. Readers' performance for the nodule detection was evaluated by ROC analysis. The combination of postprocessing techniques (STS-MIP or STS-VR) using thin section image data from MDCT improved the accuracy of detection of lung nodules significantly. There is no statistically significant difference in the detectability of lung nodules between the scrolling through thin section images and the scrolling through thick section images.
Hideki Otsuka, Graham Michael, Akiko Kubo and Hiromu Nishitani : Clinical utility of FDG PET., The Journal of Medical Investigation : JMI, Vol.51, No.1-2, 14-19, Feb. 2004.
(Summary)
The aim of this article is to introduce the clinical utility of FDG PET as oncologic imaging. PET (positron emission tomography) is a newly developed imaging tool, and it has increased the accuracy of metabolic mapping of numerous malignancies, with significant impact on the management of cancer patients for initial staging, restaging and therapy monitoring. PET can provide functional information in addition to morphology from conventional imaging modalities. 18F-labeled 2-fluoro-2-deoxyglucose (FDG) is the most commonly used PET tracer and FDG PET can demonstrate the activity of glucose metabolism throughout the entire body in a single session. We describe the clinical utility of FDG in PET and display images of normal distribution and of patients with head and neck and lung cancer.
(Keyword)
Data Interpretation, Statistical / Female / Fluorodeoxyglucose F18 / Head and Neck Neoplasms / Humans / Lung Neoplasms / Male / Neoplasms / Tomography, Emission-Computed
Bollos Anne Christine L. Leah, Ryosuke Kasai, Shoichiro Takao, kawabata Yuka, Tetsuya Tanioka, Hitoshi Ikushima and Hideki Otsuka : Multimodal Image Analysis for Cardiac Sarcoidosis: A Narrative Review, 6TH SPUP INTERNATIONAL INTERDISCIPLINARY RESEARCH CONFERENCE, Tuguegarao City ,Philippines, Aug. 2023.
Bollos Leah, Zhao Yueren, Hirokazu Ito, Yuko Yasuhara, Kyoko Osaka, Tetsuya Tanioka and Hideki Otsuka : Examination of Items Necessary for the Development of the "Technological Competency as Caring in Medicine Instrument (TCCMI), 4TH INTERNATIONAL CONFERENCE ON TECHNOLOGICAL COMPETENCY AS CARING IN NURSING AND HEALTH SCIENCES 2022, WEB, Dec. 2022.
(Keyword)
Technological competency as caring in medicine / Instrument development / Compassion, Empathy / Patientcentered care / Literature review
3.
Tamaki Otani, Hitoshi Ikushima, Yoshimi Bando, Kenmei Kuwahara, Hideki Otsuka, Kazuya Kondo and Hirokazu Miyoshi : Efficacy of 18F-fluorothymidine and 18F-fluorodeoxyglucose Positron Emission Tomography in Determining a Radiotherapy Effect., Annual Congress of the European Association of Nuclear Medicine, Oct. 2021.
4.
Tamaki Otani, Hideki Otsuka, Koh Matsushita, 音見 陽一, Yamato Kunikane, Shota Azane and Hirokazu Miyoshi : Possibility of Shortening Examination Time in Amyloid PET using 18F-Flutemetamol., Society of Nuclear Medicine and Molecular Imaging 2020 annual meeting, Jul. 2020.
5.
Youichi Otomi, Hideki Otsuka, Kaori Terazawa and Masafumi Harada : An increased physiological fluorodeoxyglucose uptake in the liver and blood pool among patients with renal failure, ECR 2019, Wien, Feb. 2019.
6.
Moriaki Yamanaka, Youichi Otomi, Kaori Terazawa, Ryota Bando, Hideki Otsuka and Masafumi Harada : To compare diagnostic ability of thallium-201 SPECT for brain tumor between quantitative evaluation, semi- quantitative evaluation and ADC values upon MRI., JNM, Vol.59, No.1, 1434, Philadelphia, Jun. 2018.
7.
Youichi Otomi, Kaori Terazawa, Hideki Otsuka, Moriaki Yamanaka, Michiko Kubo and Masafumi Harada : The relationship between the tumor FDG uptake, metastatic potential, and the FIGO stage in patients with uterine cervical cancer, JNM, Vol.59, No.1, 393, Philadelphia, Jun. 2018.
8.
Yuki Matsumoto, Yuki Kanazawa, Toshiaki Sasaki, Natsuki Ikemitsu, Hiroaki Hayashi, Mitsuharu Miyoshi, Masafumi Harada and Hideki Otsuka : Which is More Important for Quantitative Susceptibility Mapping? SNR of Phase vs Spin Dephasing., Radiological Society of North America (RSNA), Chicago, Nov. 2017.
9.
Yuki Matsumoto, Yuki Kanazawa, Toshiaki Sasaki, Natsuki Ikemitsu, Hiroaki Hayashi, Mitsuharu Miyoshi, Masafumi Harada and Hideki Otsuka : Phase Correction for Quantitative Susceptibility Mapping (QSM) using T2* Mapping, The 5th International Congress on Magnetic Resonance Imaging, Vol.2017, No.FA, 111, Seoul, Mar. 2017.
(Summary)
Objectives : The purpose of this study is to develop a phase correction method focusing on the SNR of phase and to improve the quantitative measurement of QSM. Methods : On a 3.0 T MRI system (Discovery MR750; GE Healthcare), using three-dimensional spoiled gradient-echo (3D-SPGR) sequence with multiple TEs were used in this study. The imaging parameters were TE, 12 echoes from 3.1 to 51.7 ms (ΔTE = 4.4 ms); repetition time, 55.5 ms; spatial resolution, 1.0 × 1.0 × 1.0 mm; and pixel bandwidth, 244.1 Hz. We conducted a phantom experiment in this study. Five tubes were filled with different concentrations (100, 150, 200, 250, and 300 mg/mL) of calcium hydroxyapatite samples. In this study, we focused on the computation of off-set frequency of each voxel (i.e., field map estimation). At first, we calculate the TE having the maximum for our setting number of echo from the measured T2* map. Second, the ``appropriate TE dataset'' was defined as the maximum SNR dataset with appropriate TE and two datasets with neighboring TE. Third, after estimating the field map using the appropriate TE dataset, a corrected phase angle at each phase angle of the appropriate TE dataset was calculated from a mean resultant length which is the length of the average vectors calculated from all phase angles. Then, the corrected phase angle was defined from mean resultant length. Finally, all phase angles in FOV were corrected for each appropriate TE dataset. Results : The linearity of the relationship between the measured susceptibility and the concentration of hydroxyapatite in the corrected phase dataset was significantly higher than other methods (R = 0.30 VS 0.97). Conclusions : The correction method in QSM using phase correction method makes it possible to more accurately obtain susceptibility information of tissue having a short T2*.
(Keyword)
QSM / echo time / T2* / SNR of phase / susceptibility
10.
Yuki Matsumoto, Yuki Kanazawa, Nattsuki Ikemitsu, Toshiaki Sasaki, Hiroaki Hayashi, Mitsuharu Miyosh, Masafumi Harada and Hideki Otsuka : Proposal of an appropriate echo time-input function for quantitative susceptibility mapping., International Conference On Medical Physics (ICMP) 2016, Bangkok, Dec. 2016.
(Summary)
Purpose To improve the quantitative assessment for both diamagnetic and paramagnetic materials, we developed a quantitative susceptibility mapping (QSM) method using an appropriate echo time (TE)-input function. Methods On 3.0 T MR system, we performed a phantom experiment using a multi-echo spoiled gradient-echo (12 echos; delta TE = 4.4 ms). The phantom consisted of gadopentetate dimeglumine (Gd-DTPA) and hydroxyapatite samples, which were made using three different concentrations of each material. After a multiple TE dataset was acquired, T2* values were calculated from the dataset. When a field map estimation was computed, the appropriate T2* value was used as TE-input function. Next, phase unwrapping and background removal were performed. Finally, the reconstruction of QSM was performed. Moreover, we compared susceptibility values derived from TE-input function and conventional methods. Results The mean T2* values of each Gd-DTPA and hydroxyapatite sample were 365 ± 74, 194 ± 9, 86 ± 3, 24 ± 2, 14 ± 1, and 11 ± 1 ms, respectively. Compared with the conventional method, the proposed TE-input function method indicated good positive linearity for the relationship between the Gd-DTPA concentration and susceptibility (slope = 0.26 ppm/mmol/L, R2 = 0.97, P = 0.11). Additionally, the proposed TE-input function method indicated good negative linearity for the relationship between the concentration and hydroxyapatite susceptibility (slope = -0.0019 ppm/mg/mL, R2 = 1.00, P = 0.02). Conclusions QSM with the TE-input function makes it possible to evaluate simultaneously diamagnetic and paramagnetic materials. e.g. Gd-DTPA and hydroxyapatite.
Yuki Matsumoto, Yuki Kanazawa, Hiroaki Hayashi, Kazuki Takegami, Tsuyoshi Matsuda, Masafumi Harada and Hideki Otsuka : How do you Determine the Echo Time When Calculation of Quantitative Susceptibility Mapping (QSM)?, Radiological Society of North America (RSNA) 2016, Chicago, Dec. 2016.
(Summary)
TEACHING POINTS The purpose of this exhibit is to learn that 1. It is important to know dependence of signal loss due to T2* decay, corresponding to echo time (TE) and susceptibility of biomaterial. 2. Magnetic susceptibility have paramagnetic and diamagnetic characterization, i.e., these indicate positive and negative values, respectively. TABLE OF CONTENTS/OUTLINE -Aims The aim of our study is to investigate the difference in magnetic susceptibility for various TEs. -Method On a 3.0 T MR system, we performed a phantom experiment. The phantom consisted of Gd-DTPA and hydroxyapatite samples which were made using three different concentrations of each. In order to investigate the difference in the magnetic susceptibility of each TE, multiple TEs were acquired and several TE datasets were made. Then, we analyzed with each dataset. -Results The TEs = 3.1, 7.5 and 11.9 ms datasets indicated highest positive linearity for the Gd-DTPA samples (slope = 0.244, R2 = 0.998, P = 0.021). Moreover, the TEs = 3.1, 7.5 and 11.9 ms datasets indicated highest negative linearity for the hydroxyapatite samples (slope = -0.001, R2 = 0.997, P = 0.035). -Conclusion QSM makes it possible to accurately calculation of magnetic susceptibility by using the appropriate TE.
12.
Tamaki Otani, Kazuya Kondo, Hiromitsu Takizawa, Koichiro Kajiura, Fujino Haruhiko and Hideki Otsuka : Non-Invasive Assessment of Cisplatin and Erlotinib Efficacy in Lung Cancer by Monitoring an Orthotopic SCID Mouse Model with Computed Tomography, 16th World Conference on Lung Cancer, Sep. 2015.
13.
Tamaki Otani, Hideki Otsuka, Kazuya Kondo, Hiromitsu Takizawa and Nagata Motoi : Utility of respiratory-gated PET/CT in the chronological evaluation of an orthotopic lung cancer transplantation mouse model, Annual Congress of the European Association of Nuclear Medicine, Oct. 2014.
14.
Noboru Niki, Yoshiki Kawata, Hidenobu Suzuki, Masafumi Harada, Hideki Otsuka, Junji Ueno, Mitsuo Shimada, Tetsuji Takayama, Masahiro Abe, Haruimi Itoh, Kenji Eguchi, Masahiko Kusumoto, Takaaki Tsuchida, Hironobu Ohmatsu, Masashi Takahashi, Yasutaka Nakano, Hiroaki Sakai and Yuichi Takiguchi : Computer-aided diagnosis based on computational anatomical models:Progress overview FY2009-2013, The 5th International Symposium on the Project ``Computational Anatomy'', 39-43, Mar. 2014.
15.
Hiromitsu Takizawa, Kazuya Kondo, Tamaki Otani, Ali M. Mohammed, Hideki Otsuka, Mitsuhiro Tsuboi, Koichiro Kajiura, Yasushi Nakagawa, Yukikiyo Kawakami, Mitsuteru Yoshida, Shoji Sakiyama and Akira Tangoku : Positron-emission tomography-computed tomography with the glucose analogue [18F] fluorodeoxyglucose in orthotopic implantation SCID mouse model of lung cancer, 15th World Conference on Lung Cancer, Oct. 2013.
16.
Noboru Niki, Yoshiki Kawata, Hidenobu Suzuki, Masafumi Harada, Hideki Otsuka, Junji Ueno, Mitsuo Shimada, Tetsuji Takayama, Masahiro Abe, Harumi Itoh, Masahiro Kaneko, Kenji Eguchi, Masahiko Kusumoto, Takaaki Tsuchida, Hironobu Ohmatsu, Masashi Takahashi, Yasutaka Nakano, Hiroaki Sakai and Yuichi Takiguchi : Computer-Aided Diagnosis Based on Computational Anatomical Models: Progress Overview FY2012, he 4th International Symposium on the Project ``Computational Anatomy'', 45-51, Feb. 2013.
17.
Youichi Otomi, Hideki Otsuka, Hayato Nose, Kaori Terazawa, Hitoshi Ikushima and Masafumi Harada : FDG-PET/CT in esophageal lesions other than squamous cell carcinoma and adenocarcinoma, Miami, Jun. 2012.
18.
Youichi Otomi, Hideki Otsuka, Hayato Nose, Kaori Terazawa, Hitoshi Ikushima and Masafumi Harada : Does the H/M ratio of I-123 MIBG match the cardiac function in Parkinson's disease patients?, Miami, Jun. 2012.
Keita Ishimatsu, Shinsuke Saita, Mitsuru Kubo, Yoshiki Kawata, Noboru Niki, Hideki Otsuka, Hiromu Nishitani, Hironobu Ohmatsu, Kenji Eguchi, Masahiro Kaneko and Noriyuki Moriyama : Method for lung cancer detection in PET/CT image, International Forum on Medical Imaging in Asia 2009, Vol.108, No.385, 105-110, Taiwan, Jan. 2009.
Proceeding of Domestic Conference:
1.
Locsin Leah Anne Christine Bollos, Youichi Otomi, 岡田 直子, Tomoki Matsushita, Hideki Otsuka, Ryosuke Kasai, Shoichiro Takao, Koji Fujita, Yuishin Izumi, Takayoshi Shinya, Hitoshi Ikushima and Masafumi Harada : Comparative Imaging of Creutzfeldt-Jakob Disease: Two Cases with and without CCD, 第141回日本医学放射線学会中国・四国地方会, Dec. 2024.
2.
Youichi Otomi, Takanori BANDOH, Hideki Otsuka, Ryosuke Kasai, Tamaki Otani, Yamato Kunikane, 岡田 直子, Tomoki MATSUSHITA, Takashi Kawanaka, Takayoshi Shinya and Masafumi Harada : Clinical practice of peptide receptor radionuclide therapy in Tokushima University Hospital, 第64回日本核医学会学術総会/第44回日本核医学技術学会総会学術大会, Nov. 2024.
3.
Tomoki Matsushita, Youichi Otomi, Ryosuke Kasai, Locsin Leah Anne Christine Bollos, 岡田 直子, Junichiro Hiraoka, Yukiko Takaoka, Ryota Mitsuhashi, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : Nuclear Medicine Examination in the Evaluation of Cardiomyopathy, 第64回日本核医学会学術総会/第44回日本核医学技術学会総会学術大会, Nov. 2024.
Bollos Leah, Ryosuke Kasai, Youichi Otomi, Shoichiro Takao, Hitoshi Ikushima, Hideki Otsuka and Masafumi Harada : Prediction model of coronary artery calcification risk basis for radiomics features of pericoronary fat in coronary computed tomography, 第59回日本医学放射線学会秋季臨床大会, Sep. 2023.
14.
Youichi Otomi, Hideki Otsuka, Michiko Kubo, 東 航平, Seiji Iwamoto, Takayoshi Shinya and Masafumi Harada : Let us read lymphatic flow properly!, 第82回日本医学放射線学会総会, Apr. 2023.
15.
Yuka Hiroshima, Takayoshi Shinya, Hitoshi Ikushima, Youichi Otomi, Hideki Otsuka, Chisato Tonoiso, Akiko Kubo, Takashi Kawanaka, Yasushi Takagi and Masafumi Harada : Multi-modality Imaging for the Patients with Metastatic Brain Tumors After Stereotactic Irradiation, The 82nd Annual Meeting of the Japan Radiological Society, Apr. 2023.
Youichi Otomi, Takayoshi Shinya, Hideki Otsuka and Masafumi Harada : Frequency of FDG-avid supraclavicular lymph nodes and the number of FDG-avid lymph nodes on PET/CT after vaccination: COVID-19 vs. influenza, 第81回日本医学放射線学会総会, Apr. 2022.
21.
Takayoshi Shinya, Okada Naoko, MATSUSHITA Tomoki, Saya Matsuzaki, Yuki Matsumoto, Youichi Otomi, Michiko Kubo, Hideki Otsuka and Masafumi Harada : Review of Multimodality Imaging in Small Bowel Tumors: a review of old and new techniques, 第81回日本医学放射線学会総会, Apr. 2022.
Takaaki Isayama, Sadamitsu Nishihara, Kaita Terahara and Hideki Otsuka : 一般撮影装置における面積線量計の検討, Japanese Journal of Radiological Technology, Vol.73, No.9, 951, Oct. 2017.
38.
Keita Terahara, Sadamitsu Nishihara, Takaaki Isayama, 湯浅 将生, Ryosuke Kasai, 由井 和茂 and Hideki Otsuka : 薄型CTファントムを用いたノンヘリカルスキャンで体軸方向のCT値を計測, Japanese Journal of Radiological Technology, Vol.73, No.9, 821, Oct. 2017.
39.
Yuki Matsumoto, Yuki Kanazawa, Masafumi Harada, Hiroaki Hayashi, Kotaro Baba, Mitsuharu Miyoshi and Hideki Otsuka : Off-set frequency correction in brain for quantitative susceptibility mapping, JSMRM2017, Sep. 2017.
40.
Yuki Matsumoto, Yuki Kanazawa, Masafumi Harada, Hiroaki Hayashi, 馬場 幸太郎, 幸坂 育歩, 三好 光晴 and Hideki Otsuka : 定量的磁化率マッピング(QSM)のためのオフセット周波数補正法の提案, Society of Advanced Medical Imaging (SAMI) 2017, Jul. 2017.
41.
Yuki Matsumoto, Yuki Kanazawa, Toshiaki Sasaki, Hiroaki Hayashi, Natsuki Ikemitsu, Masafumi Harada and Hideki Otsuka : Evaluation of Mechanical Waves of MR Elastography, JSRT, Apr. 2017.
(Summary)
[Purpose] The purpose of our study is to assess the mechanical waves that occur during MR elastography using circular statistical analysis. [Methods] On a 1.5 T MR system, we performed a phantom experiment. The phantom was composed of two blocks of agar at a concentration of 0.75 and 1.0 wt%. All imaging data were acquired using gradient echo (GRE) specialized for MRE. The imaging parameters were TE, 19.4 ms; repetition time, 50 ms; field of view, 420 × 420 mm; slice thickness, 80 mm; bandwidth 32.3 kHz; motion-encoding gradient frequency, 60 Hz; driver amplitude, 70. After acquiring the dataset, MRE images were calculated from a multi scale direct inversion algorithm. Additionally, we measured mean wavelength values of offset phase images obtained during MRE using circular statistical analysis. [Results] Mean shear stiffness values at 0.75 wt% and 1.0 wt% agar concentrations were 1.95 ± 0.35 and 6.45 ± 0.97 kPa, respectively. Mean wavelength values for each agar concentration at three column line profile settings (from left to right side) were 1000 and 1920 mm for the 20th column, 760 and 1880 mm for the 90th column, and 160 and 1960 mm for the 160th column, respectively. [Conclusion] Circular statistical analysis makes it possible to obtain and evaluate more detailed information during MRE.
Yuki Matsumoto, Yuki Kanazawa, 池光 捺貴, 佐々木 俊晃, 臼田 貴俊, Hiroaki Hayashi, 三好 光晴, Masafumi Harada and Hideki Otsuka : How to make a phantom for quantitative susceptibility mapping., 第44回日本放射線技術学会秋季学術大会, Oct. 2016.
44.
Yuki Matsumoto, Yuki Kanazawa, Nattsuki Ikemitsu, Toshiaki Sasaki, Hiroaki Hayashi, Mitsuharu Miyosh, Masafumi Harada and Hideki Otsuka : Noise estimation of phantom phase image in ultra-short echo time imaging, JSMRM2016, Sep. 2016.
(Summary)
Purpose: To estimate accurately noise of phase rotation, we evaluated a signal phase of ultra-short echo time (UTE) imaging. Materials and Methods: On 3.0T MR system, we performed a phantom experiment using a dual-echo UTE imaging. The imaging parameters were TE, 0.032 ms (first-echo) and 3.3 ms (second-echo); matrix sizes, 256 ×256; slice, 16. The phantom consisted of Gd-DTPA and hydroxyapatite samples, which were made using three different concentrations of each material; Gd-DTPA, 0.5, 1.0, and 2.5 mmol/L; hydroxyapatite, 100, 200, and 350 mg/mL. Then, region of interest analysis was performed on two phase images, e.g., first-echo, and second-echo phase images. Results: The mean first-echo phase values on each Gd-DTPA (0.5, 1.0, and 2.5 mmol/L) and hydroxyapatite (100, 200, and 350 mg/mL) sample were 32.4 ± 0.04, 32.2 ± 0.04, 32.0 ±0.01, 32.4 ± 0.02, 43.6 ± 0.03, and 60.0 ± 0.01 degree, respectively. The mean second-echo phase values on each Gd-DTPA (0.5, 1.0, and 2.5 mmol/L) and hydroxyapatite (100, 200, and 350 mg/mL) sample were 39.1 ± 0.04, 36.0 ± 0.04, 35.5 ± 0.05, 137.9 ± 0.06, 83.4 ± 0.06, and 88.02 ± 0.06 degree, respectively. The mean background phase value first-echo, and second-echo were 33.5 ± 0.11 and 87.1 ± 0.12 degree, respectively. Discussion & Conclusion: The phase rotation of hydroxyapatite occurred difference of phase value in each sample, i.e., this leads good contrast in UTE image. In contrast, the phase rotation of Gd-DTPA at TE 0.032 ms is small enough to estimate noise because the Gd-DTPA phase values were almost equal. Thus, UTE imaging may lead to noise derived from a phase rotation. Noise estimation using UTE imaging may render it possible to obtain more detailed information of paramagnetic materials, e.g., Gd-DTPA.
45.
小畠 巧也, Yuki Kanazawa, 小川 和郎 and Hideki Otsuka : Simulation of blood signal in non-contrast-enhanced MR angiography with three-dimension fast spin-echo sequence, 第72回日本放射線技術学会総会学術大会, Apr. 2016.
46.
Yuki Matsumoto, Yuki Kanazawa, Usuda Takatoshi, Hiroaki Hayashi, Matsuda Tsuyoshi, Masafumi Harada and Hideki Otsuka : Dependence on echo time for quantitative susceptibility mapping (QSM) MRI., JSRT, Apr. 2016.
47.
Usuda Takatoshi, Yuki Kanazawa, Yuki Matsumoto, Hiroaki Hayashi, Masafumi Harada, Hideki Otsuka and Matsuda Tsuyoshi : Normalization of time-dependent signal change of MRI, JSRT, Apr. 2016.