Takuya Mitsumoto

National Center for Global Health and Medicine in Japan, Edo, Tōkyō, Japan

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Publications (13)33.58 Total impact

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    ABSTRACT: PURPOSE Evaluation of inflammatory lung diseases in PET with 18F-FDG-PET/CT has been based on the focal evaluation using region of interest (ROI). We developed software to evaluate the total lung density (HU) and FDG uptake (SUV) in collaboration with Siemens Japan. The goal of this study was to build the normal data base for quantitative diagnosis of inflammatory lung disease. METHOD AND MATERIALS We enrolled 93 healthy subjects that did not have abnormality on chest X-rays and a respiratory function test. We measured SUV, HU and lung volume in total lung by software. We conducted univariate and multivariate analysis about association of age, sex, height, weight, body mass index (BMI), blood glucose level, Brinkman index, smoking, lung volume, percent-predicted forced vital capacity (%FEV) and percent predicted forced expiratory volume in 1 second (%FVC) in both SUV and HU. In addition, we evaluated association between HU and SUV. RESULTS In SUV, the significant factors were weight, BMI, Brinkman index, %FEV, %FVC, lung volume, smoking and HU. In HU, the significant factors were age, weight, BMI, %FEV, %FVC, lung volume, and SUV. BMI and HU were identified as significant factors for total lung SUV by stepwise multiple regression analysis (P < 0.01). Also, significant factors of total lung HU were age, lung volume and SUV (P < 0.01). CONCLUSION We have successfully developed a normal data base of the lung total HU and total SUV. Among normal subjects, various factors affected these indices such as smoking, BMI, age etc. CLINICAL RELEVANCE/APPLICATION Our new methods may be useful for quantitative evaluation of inflammatory lung disease with FDG-PET/CT.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: PURPOSE We compared the maximum and peak standard uptake values (SUV max, SUV peak) measured from PET image reconstructed with 3D-OSEM (HD) and 3D-OSEM-PSF (HD-S), using NEMA body phantom. The purpose of this study was to determine effect of PSF correction base on SUV max and SUV peak. METHOD AND MATERIALS The PET/CT device was performed using a Discovery PET/CT 600. The NEMA/IEC body phantom and the scatter phantom were used according to NEMA NU-2 2007. The hot spots were filled with 18F-FDG of 20 kBq/ml and the background radioactivity was set at 5 kBq/ml so that the ratio of radioactivity concentration of the hot spots and background would be 4:1. The radioactivity of the scatter phantom was set at 100 MBq. The reconstruction images extracted both HD and HD-S, iteration number of reconstruction parameter was changed from 1 to 19 at the constant subset number of 16. We measured SUV max and the SUV peak. The SUV peak assumed 1.2cm diameter region of interest that placed on the center of sphere. RESULTS The value of SUV max and SUV peak were significantly improved using HD-S as compared with HD. HD-S had higher SUV values related to the resolution recovery and the edge artifacts, that enhance the image values near the sharp edges in the image. The SUV max from HD-S overestimated the value (up to 13% and 15% measured with the 17 mm and 22 mm sphere). In contrast, in the SUV peak, the effect of the overcorrection was not observed. CONCLUSION HD requires enormous computational complexity for signal recovery, but HD-S can realize the improvement of parameter condition, and better clinical usage. However, SUV max overestimated the SUV value with PSF correction. CLINICAL RELEVANCE/APPLICATION When PSF correction is applied in a diagnosis, we recommend SUV peak in order that a problem of the overcorrection occurs in SUV max.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: An 82-year-old man with suspected systemic amyloidosis and complete atrioventricular block underwent vascular biopsy during his pacemaker implantation with pathology showing amyloid deposits. 99mTc-aprotinin SPECT revealed increased radiotracer uptake along the left ventricular wall, consistent with cardiac amyloidosis. 11C-PiB PET/CT performed for the evaluation of amyloid deposits in the brain showed findings suggestive of Alzheimer disease without abnormal radiotracer concentration in the myocardium to match the 99mTc-aprotinin SPECT findings. Dynamic PET images showed increased 11C-PiB concentration in the left ventricular myocardium at 2 minutes after injection, with subsequent tracer clearance by approximately 5 minutes, consistent with normal 11C-PiB biodistribution.
    Clinical nuclear medicine 08/2012; 37(8):807-9. · 3.92 Impact Factor
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    ABSTRACT: OBJECTIVE: Vocal cord palsy (VCP) is a potential cause of hoarseness that results in decreasing mobility of the vocal cord. VCP can arise from a variety of causes; so, systematic screening is warranted for the management of patients with VCP. Asymmetrical fluorodeoxyglucose (FDG) uptake in vocal cords is a well-known feature in patients with VCP, but no detailed analysis has been performed. This study aimed at reevaluating the (18)F-FDG positron emission tomography/computed tomography (PET/CT) for patients with VCP. METHODS: We retrospectively surveyed the results of FDG-PET/CT for 59 patients with VCP, compared to laryngoscopic findings. Quantitative analysis was performed using maximum standardized uptake value (SUV(max)), and regions of interest were drawn over bilateral vocal cords as confirmed from the CT portion of PET/CT. Patients were divided into 3 groups: Group 1 (n = 14), in which VCP was caused by the lesion of the laryngeal area; Group 2 (n = 40), in which VCP was caused by the lesion on the root of the recurrent laryngeal nerve; and Group 3 (n = 5), in which VCP was caused by the lesion from the vagal center to the proximal vagus nerve. RESULTS: For Group 1, higher FDG uptake in the paralyzed vocal cord was seen in 86 % of patients (mean SUV(max) 8.1 ± 5.3 vs. 2.3 ± 0.4, paralyzed vs. non-paralyzed, respectively; P < 0.002). The sensitivity of FDG-PET/CT for indicating the lesion causing VCP was 79 % for Group 1. Group 2 showed dominant FDG uptake in the non-paralyzed vocal cord (mean SUV(max) 2.1 ± 0.9 vs. 1.5 ± 0.4, non-paralyzed vs. paralyzed, respectively; P < 0.001). The sensitivity of FDG-PET/CT for indicating the lesion causing VCP was 93 % for Group 2. Group 3 showed no statistically significant difference in FDG accumulation between non-paralyzed and paralyzed vocal cords (mean SUV(max) 1.8 ± 0.3 vs. 1.7 ± 0.3, non- paralyzed vs. paralyzed, respectively; P = 0.30). The sensitivity of FDG-PET/CT for indicating the lesion causing VCP was 60 % for Group 3. CONCLUSIONS: FDG accumulation in the vocal cords is dependent on the lesion site causing VCP. In addition, FDG-PET/CT can contribute to identification of the lesion responsible for inducing VCP.
    Annals of Nuclear Medicine 03/2012; · 1.41 Impact Factor
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    ABSTRACT: A new tracer, 4'-[methyl-(11)C]-thiothymidine ((11)C-4DST), has been developed as an in vivo cell proliferation marker based on the DNA incorporation method. This study evaluated the potential of (11)C-4DST PET/CT for imaging proliferation in non-small cell lung cancer (NSCLC), compared with (18)F-FDG PET/CT. Eighteen patients with lung lesions were examined by PET/CT using (11)C-4DST and (18)F-FDG. We constructed decay-corrected time-activity curves of 9 major regions as the mean standardized uptake value. We then compared the maximum standardized uptake value (SUVmax) of lung tumors on both (11)C-4DST and (18)F-FDG PET/CT with the Ki-67 index of cellular proliferation and with CD31-positive vessels as a marker of angiogenesis in surgical pathology. NSCLC was pathologically confirmed in 19 lesions of 18 patients. Physiologic accumulation of (11)C-4DST was high in liver, kidney, and bone marrow and low in aorta, brain, lung, and myocardium. Biodistribution of (11)C-4DST was almost stable by 20 min after injection of (11)C-4DST. Mean (11)C-4DST SUVmax for lung cancer was 2.9 ± 1.0 (range, 1.5-4.7), significantly different from mean (18)F-FDG SUVmax, which was 6.2 ± 4.5 (range, 0.9-17.3; P < 0.001). The correlation coefficient between SUVmax and Ki-67 index was higher with (11)C-4DST (r = 0.82) than with (18)F-FDG (r = 0.71). The correlation coefficient between SUVmax and CD31 was low with both (11)C-4DST (r = 0.21) and (18)F-FDG (r = 0.21), showing no significant difference between the tracers. A higher correlation with proliferation of lung tumors was seen for (11)C-4DST than for (18)F-FDG. (11)C-4DST PET/CT may allow noninvasive imaging of DNA synthesis in NSCLC.
    Journal of Nuclear Medicine 12/2011; 53(2):199-206. · 5.77 Impact Factor
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    ABSTRACT: PURPOSE 4’-[Methyl-11C] Thiothymidine ([11C]4DST) is a new tracer for in vivo DNA synthesis, developed by Toyohara J et al. We evaluated the potential of [11C]4DST PET/CT for imaging DNA synthesis in NSCLC, compared with [18F]FDG. METHOD AND MATERIALS Total 14 patients with lung lesions were performed PET/CT using [11C]4DST and [18F]FDG. We compared maximum standardized uptake value (SUV max) of [11C]4DST and [18F]FDG for lung tumor with MIB-1(Ki-67) as proliferation index in pathological specimens after surgery. The correlations with CD31 and GLUT1 were also examined. RESULTS NSCLC was pathologically proved in 12 patients with 13 lesions. Mean [11C]4DST SUVmax for lung cancer was 3.1±1.0 (range: 1.9-4.7), and mean [18F]FDG SUVmax 7.3±4.7 (range:1.3-13.7). The correlation coefficient (r) between SUVmax and MIB-1index was higher with 4DST (r=0.67) than with [18F]FDG ( r=0.60). Moreover the correlation coefficient between SUVmax and number of CD31 positive cell was higher with 4DST ( r=0.66) than with [18F]FDG ( r=0.59). CONCLUSION [11C]4DST represented higher correlation with proliferation of lung tumors than [18F]FDG. [11C]4DST PET/CT may reveal noninvasive imaging for DNA synthesis of NSCLC. CLINICAL RELEVANCE/APPLICATION New PET tracer [11C]4DST for DNA Synthesis imaging
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: The performance of two PET examinations, one using L-[methyl-¹¹C] methionine (MET) and one using 2-[¹⁸F] fluoro-2-deoxy-D-glucose (FDG), on the same day may offer a clinical advantage for the investigation of brain tumors or other lesions. The purpose of this study was to investigate the effect of positron cross-talk (PCT) and to determine the optimal protocol for using MET and FDG on the same day. The participants comprised 62 patients with head and neck cancer. We focused on the high physiological uptake of MET in the liver and evaluated the effect of PCT with MET on FDG uptake in the liver and muscle. Three FDG-PET scans [one: whole body (early image), two: head and neck, and three: one-bed-position scan of the liver (delayed image)] were performed after completing a MET-PET scan (head and neck) at varying injection intervals. Standard uptake value mean variations in the liver and muscle were calculated, assuming that the differences between the early and the delayed images reflected the PCT from carbon-11 on fluorine-18, on the basis of the results of a phantom study and a study in volunteers. The participants were categorized into four groups (G) according to the injection interval: G1 (n=15, 30-49 min), G2 (n=16, 50-69 min), G3 (n=17, 70-89 min), and G4 (n=14, ≥ 90 min). The PCT level decreased from the G1 group through to the G3 group (analysis of variance, P<0.001) but was stable, with no further decrease in the G4 group. The PCT level in the muscle was not significantly different among the G1, G2, G3, and G4 groups (analysis of variance, P=0.693). Thus, PCT in the liver decreased at longer injection intervals, and PCT was no longer observed at injection intervals of more than 90 min. MET and FDG-PET examinations can be successfully performed on the same day without PCT between the studies if the injection interval is longer than 90 min. This method reduces the examination burden of patients and may be useful for performing multiple PET examinations while the patient's condition remains almost the same.
    Nuclear Medicine Communications 11/2011; 33(3):297-304. · 1.38 Impact Factor
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    ABSTRACT: To determine the cut-off value for distinguishing a normal versus an abnormal right-to-left shunt percentage on lung perfusion scintigraphy using (99m)Tc-macroaggregated albumin (MAA). Fifty-three patients (eight patients with a right-to-left shunt and 45 without a right-to-left shunt) who underwent MAA whole-body imaging for the evaluation of right-to-left shunts were divided into group 1 (eight patients with brain MAA uptake) and group 2 (45 patients without brain MAA uptake). Moreover, group 2 was subdivided into two categories (groups 2a and 2b) based on the results of lung computed tomography, electrocardiography examinations, and pulmonary function tests. The average and standard deviation (SD) of each group were compared. In addition, we estimated the cut-off value for a normal right-to-left shunt percentage using whole-body imaging. The average right-to-left shunt percentage values and SD were 23.67±12.17% in group 1, 6.68±1.04% in group 2a, and 6.60±0.84% in group 2b. The shunt percentages of groups 2a and 2b were not significantly different (P=0.77). The estimated normal value (mean±2 SD) of group 2 was 6.64±0.94%. Meanwhile, the cut-off value was estimated as 10% based on the distributions of MAA shunt percentages for groups 1 and 2. The normal range (mean±2 SD) was 6.64±1.88%. The cut-off value for the normal right-to-left shunt percentage in MAA scintigraphy was 10%.
    Nuclear Medicine Communications 10/2011; 32(10):936-40. · 1.38 Impact Factor
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    ABSTRACT: Case Report. A 66-year-old woman, who had history of surgical resection of tongue cancer and implantation of a pacemaker for sick sinus syndrome, complained of a recurring fever and dry cough for 2 months. Because the origin of the fever was not clear and because of a high inflammatory reaction with a white blood cell count of 12650/lL and a C-reactive protein (CRP) of 20.3 mg/dL, she was referred to our hospital for further examination. Contrast enhanced computed tomography (CECT) was first performed to investigate the focus of the fever. CECT showed irregular thickness with heterogeneous contrast enhancement of the left atrium and the ventricle wall. Lymph node swelling at the mediastinal and paraaortic region was also seen continuous to the lesion in the left ventricle wall (Figure 1). Since the CECT was performed without ECG gating or dynamic contrast enhancement, evaluation of the coronary arteries was not adequate, even though the proximal left coronary artery (LCA) appeared to pass through the thickened wall. Coronary angiography showed no evidence of vascular infiltration in a coronary artery, but abnormal vascularization presenting as a feeding artery to the cardiac mass was confirmed in the LCA (Figure 2). A trans-catheter biopsy of the cardiac tumor was performed at the same time, but the biopsy specimen did not indicate pathological malignancy. Both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) revealed a 2.5 9 5.5 cm low echoic lesion along the cardiac wall from the left atrium to ventricle. Left ventricular function was good with an ejection fraction of 60.4%. Ga-67 scintigraphy showed abnormal uptake at the mediastinum and weak uptake in the left ventricle wall (Figure 3). Dual imaging with Tl-201 and iodine-123 beta-methyl-iodophenyl-pentadecanoic acid ( 123 I-BMIPP) revealed no evidence of myocardial ischemia. In addition, abnormal uptake as an indication of cardiac tumor was not confirmed in this case (Figure 4). [ 18 F]-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) was performed using intravenous contrast agent to define the structure of the cardiac wall (Figure 5). FDG-PET/CT showed high FDG accumulation in the heart and mediastinum. FDG was diffusely accumulated in the cardiac wall, and appeared to spread over the thickened left atrium to the ventricle wall, as defined in CECT. The FDG-avid area extended to the mediastinal and paraaoric region, and was suspected to be the invasive lesion from the cardiac tumor. In addition, the FDG-avid area was much more extensive than the area of abnormal uptake on Ga-67 scintigraphy, especially for a cardiac lesion.
    Journal of Nuclear Cardiology 03/2011; 18(3):516-20. · 2.85 Impact Factor
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    ABSTRACT: Fluorodeoxyglucose (FDG) uptake in joint lesions in patients with rheumatoid arthritis (RA) reportedly represents the degree of synovial inflammation. Most previous studies have focused on small joints, and the application of whole-body positron emission tomography (PET) combined with computed tomography (CT) (PET/CT) for the evaluation of inflammatory activity in large joints has not been well studied. Eighteen patients with RA underwent FDG-PET/CT. FDG uptake in the knee, hip, carpal, wrist, elbow, shoulder, and atlanto-axial joint (total of 13 joints) and in the axillary lymph nodes was evaluated by calculating the maximum standardized uptake value (SUV(max)) and the visual uptake scores as follows: 0, no uptake; 1, slight uptake; 2, moderate uptake (same as in liver); 3, higher than in liver; 4, highest uptake. The number of painful/swollen joints, the white blood cell (WBC) count, and the C-reactive protein (CRP) level were also evaluated. Whole-body FDG-PET/CT delineated large-joint lesions in patients with RA, and the metabolic activity of inflammation was accurately overlaid on the joint anatomy. The total FDG score for all 13 joints was significantly correlated with the CRP level (r = 0.653, p < 0.01, n = 18). The total SUV(max) and the CRP level were weakly, but not significantly, correlated (r = 0.377, p > 0.05). The WBC count was not correlated with any other parameter. The mean number of joints per patient with an FDG uptake score of 2 or more was significantly larger than the mean number of painful/swollen joints (6.2 +/- 3.3 vs. 3.1 +/- 2.7, n = 18, p < 0.01) and both parameters were strongly correlated (r = 0.588, p < 0.01, n = 18). Also, FDG uptake score and SUV of painful/swollen joints were significantly higher than these of not painful/swollen joints. FDG uptake was significantly different from patients of remission and patients of active arthritis. Uptake in the atlanto-axial joint was observed in five (mostly asymptomatic) patients (5/18, 28%), and the uptake score was significantly correlated with the total FDG score (r = 0.669, p < 0.01, n = 18). The axillary lymph nodes score was correlated with the arm joints score. FDG-PET/CT represents the inflammatory activity in large joints in patients with RA accurately and sensitively and may be helpful for early evaluations of the extent of RA throughout the whole body including high risk lesion of atlanto-axial joint. Furthermore, the visual FDG uptake score may be useful for evaluating arthritis in large joints.
    Annals of Nuclear Medicine 10/2009; 23(9):783-91. · 1.41 Impact Factor
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    ABSTRACT: Tissue uptake of l-[methyl-(11)C]-methionine ((11)C-methionine) has been used to monitor amino acid metabolism and protein synthesis. We examined whether (11)C-methionine was retained in areas of myocardial infarction after successful reperfusion. Nine patients with infarction in the left anterior descendent region underwent percutaneous transluminal coronary artery intervention within 24 h and (201)Tl SPECT, (18)F-FDG PET, and (11)C-methionine PET within 2 wk of infarction onset. The standardized uptake values of the infarcted area and of the normal area were measured. The (11)C-methionine images showed increased uptake in the infarcted area, whereas the (201)Tl SPECT and (18)F-FDG PET images showed decreased uptake. The highest accumulation of (11)C-methionine in the infarcted area was observed during the early phase of AMI. (11)C-methionine uptake is elevated in infarcted areas and may reflect the early acute phase of damage healing, that is, the initial process of remodeling.
    Journal of Nuclear Medicine 09/2009; 50(8):1283-7. · 5.77 Impact Factor
  • Clinical nuclear medicine 08/2009; 34(7):466-9. · 3.92 Impact Factor
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    ABSTRACT: The purpose of this investigation was to monitor the localization and migration of 125I seeds after permanent brachytherapy for prostate cancer using a new scintigraphic technique that may overcome the drawbacks of conventional x-ray methods. 125I seeds emit gamma-rays with an average energy peak of 28 keV. We used a gamma-camera equipped with low-energy high-resolution collimators that were tuned to an energy level of 35 keV with a 70% window width. Sixteen patients with prostate cancer were examined after 125I seed insertion. The number of seeds remaining in the prostate was confirmed using pelvic CT for postoperative dose planning; however, seeds that had migrated outside the prostate could not be detected. Furthermore, the migrated seeds were not completely traceable using chest or abdominal radiography. Thus, we adopted a scintigraphic technique to perform this task. The evaluation of radiography and scintigraphy findings was masked, and the rates of migrated seed detection were statistically examined using the McNemar test. To localize the migrated seeds, we fused the scintigraphic images of the migrated seeds and the patients' contours. Scintigraphy was successfully used to detect 20 migrated seeds of a total of 1,182 implanted seeds, whereas radiography was successfully used to detect 7. The sensitivity of the scintigraphy results was 20 of 20 (100%), whereas that of the radiography results was 7 of 20 (35%). Seed migration was detected in 11 of 16 patients (69%) using scintigraphy, whereas seed migration was detected in only 4 patients (25%) using radiography; this difference was statistically significant (P = 0.016). Scintigraphy is more effective for detecting seed migration and monitoring the localization of 125I seeds than radiography. The precise anatomic location of migrated seeds can be pinpointed using fusion images. Scintigraphy may become a standard procedure for monitoring seed migration during 125I brachytherapy in patients with prostate cancer.
    Journal of Nuclear Medicine 05/2008; 49(4):541-5. · 5.77 Impact Factor