Takafumi Mochizuki

Comparison of diagnostic value of I-123 MIBG and high-dose I-131 MIBG scintigraphy including incremental value of SPECT/CT over planar image in patients with malignant pheochromocytoma/paraganglioma and neuroblastoma.

Purpose: To compare lesion detectability of I-123 MIBG scintigraphy with that of high-dose I-131 MIBG and to evaluate incremental benefit of SPECT/CT over planar image for the detection and localization of the lesions in patients with I-131 MIBG therapy for malignant pheochromocytoma/paraganglioma and neuroblastoma. Materials and Methods: We retrospectively investigated 16 patients with malignant pheochromocytoma/paraganglioma and neuroblastoma, who were referred for I-131 MIBG therapy. We investigated the lesion detectability in 10 pairs of I-123 and high-dose I-131 MIBG studies of the same patient, obtained within 2 weeks. In 31 studies of I-123 MIBG scintigraphy in 16 patients and 17 studies of high-dose I-131 MIBG scintigraphy in 12 patients, we compared planar and SPECT/CT images for the lesion detectability and localization. Results: The number of lesions detected by I-123 MIBG planer image and SPECT/CT and high-dose planer I-131 MIBG and SPECT/CT were 3.0 and 3.7, 7.3 and 7.7 per study, respectively. SPECT/CT images provided additional diagnostic information over planar images in 25 studies (81%) of 12 patients (75%) in I-123 MIBG scintigraphy and in 9 studies (53%) of 9 patients (75%) in high-dose I-131 MIBG scintigraphy. Conclusion: Post-therapy high-dose I-131 MIBG scintigraphy is superior to I-123 MIBG scintigraphy in lesion detectability even in comparison with I-123 MIBG SPECT/CT images and high-dose I-131 MIBG planar images in patients with malignant neuroendocrine tumors. SPECT/CT images are helpful for accurate identification of anatomic localization compared with planar images.

Whole body muscle activity during the FIFA 11+ program evaluated by positron emission tomography.

Purpose This study investigated the effect of the FIFA 11+ warm-up program on whole body muscle activity using positron emission tomography. Methods Ten healthy male volunteers were divided into a control group and a group that performed injury prevention exercises (The 11+). The subjects of the control group were placed in a sitting position for 20 min and 37 MBq of 18F-fluorodeoxyglucose (FDG) was injected intravenously. The subjects then remained seated for 45 min. The subjects of the exercise group performed part 2 of the 11+for 20 min, after which FDG was injected. They then performed part 2 of the 11+for 20 min, and rested for 25 min in a sitting position. Positron emission tomography-computed tomography images were obtained 50 min after FDG injection in each group. Regions of interest were defined within 30 muscles. The standardized uptake value was calculated to examine the FDG uptake of muscle tissue per unit volume. Results FDG accumulation within the abdominal rectus, gluteus medius and minimus were significantly higher in the exercise group than in the control group (P<0.05). Conclusion The hip abductor muscles and abdominal rectus were active during part 2 of the FIFA 11+ program.

Usefulness of fluorine-18 fluorodeoxyglucose-positron emission tomography in management strategy for thymic epithelial tumors

BACKGROUND This study investigated the usefulness of fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) during the treatment of thymic epithelial tumors in combination with Ki-67 evaluation based on surgical cases in our department. METHODS Between November 2003 and May 2011, 39 patients with thymic epithelial tumor underwent preoperative FDG-PET. The maximum standardized uptake value (SUVmax) of each category within Masaoka stage, World Health Organization classification, tumor diameter, myasthenia gravis, and Ki-67 label index were compared. To examine risk factors for relapse, SUVmax, age, sex, and surgical radicality were investigated in addition to those items. RESULTS The mean SUVmax was 4.5 (range, 1.2 to 14.6) and was significantly higher for Masaoka stage IV than for I and II (all p < 0.008) and for World Health Organization classified thymic cancer compared with all other types (all p < 0.0001). Mean SUVmax revealed significantly higher values for large tumors than for small tumors (p = 0.02). Mean SUVmax was significantly higher for high Ki-67-positive samples (p = 0.0004), indicating a strong correlation between SUVmax and the Ki-67 label index (ρ = 0.77, p = 0.0001). SUVmax accurately reflected therapeutic efficacy in patients with induction therapy. Univariate analysis revealed Masaoka stages III and IV and pathologically incomplete resection as risk factors for relapse. On multivariate analysis, independent risk factors for relapse comprised only Masaoka stages III and IV. CONCLUSIONS FDG-PET SUVmax does reflect proliferation and invasiveness of thymic epithelial tumors and can provide an index for diagnosis and treatment, although it is not a risk factor for relapse. FDG-PET is also useful for evaluating induction therapy efficacy and detecting relapse.

Changes in muscle activity after performing the FIFA 11+ programme part 2 for 4 weeks.

ABSTRACT Changes in muscle activity were evaluated by positron emission tomography–computed tomography (PET–CT) after performing part 2 of the Fédération Internationale de Football Association’s 11+ programme (11+) for 4 weeks. Eleven males performed part 2 of the 11+ for 20 min before and after 37 MBq of 18F-fluorodeoxyglucose (FDG) was injected intravenously. PET–CT images were obtained 50 min after FDG injection. The participants were then instructed to perform part 2 of the 11+ 3 times per week for 4 consecutive weeks, after which another set of PET–CT images was obtained following the same procedure. Regions of interest were defined within 30 muscles. The standardised uptake value (SUV) of FDG by muscle tissue per unit volume was calculated, and FDG accumulation was compared between pre- and post-training PET–CT results. Performing part 2 of the 11+ for 4 weeks increased mean SUV in the sartorius, semimembranosus, biceps femoris, abductor hallucis, and flexor hallucis brevis muscles (P < 0.05). In conclusion, routinely performing part 2 of the 11+ for 4 weeks increased glucose uptake related to muscle activity in the hamstrings and hallux muscles. We speculate that there is some possibility of this change of muscle activity contributing to a decrease in sports-related injuries.

Innovative exercise device for the abdominal trunk muscles: An early validation study

Background Exercise is one of the few treatments that provide significant improvements in chronic low back pain (CLBP). We developed an innovative exercise device for abdominal trunk muscles. This device can be used in a sitting or standing position and contains a built-in system to measure abdominal trunk muscle strength. We examined whether subjects can adequately use the device to perform the exercises and measure their abdominal trunk muscle strength. Methods We collected data on the body height, body weight, body mass index, and girth of 30 healthy male volunteers, and measured their grip power and trunk extensor muscle strength using a dynamometer. The volunteers performed a sit-up test as an indicator of trunk flexor muscle strength, and we measured their abdominal muscle strength using the device. We then evaluated the correlations between abdominal trunk muscle strength and anthropometric parameters as well as the strength of other muscles. In subsequent tests, 5 of the 30 subjects participated in two positron emission tomography (PET) series consisting of examinations after a resting period (control study) and during exercise (exercise study). For the exercise study, the subjects performed 2 sets of exercises for 20 minutes using the device before and after an injection of 18F-fluorodeoxyglucose (FDG). PET-computed tomography images were obtained 60 minutes after FDG injection in each study. We compared the skeletal muscle metabolism of the participants in both studies using the standardized uptake value. Results The muscle strength measured by the device and the 30-second sit-up frequency were correlated. FDG accumulation within the diaphragm and abdominal rectus muscles was significantly higher in the exercise study. Conclusion Our innovative exercise device facilitates a coordinated contraction of the abdominal trunk muscles at the anterior aspect and the roof of the core, and enables subjects to measure the strength of these muscles.

Positron Emission Tomography with F-18 Fluorodeoxyglucose

Positron emission tomography (PET) with 18F fluorodeoxyglucose (FDG) is an effective method for screening throughout the entire body for organ lesions associated with IgG4-related disease (IgG4-RD). FDG, a tracer of glucose metabolism, accumulates in areas of active inflammatory changes, which are associated with enhanced glucose metabolism. In IgG4-RD, abnormal accumulation can be detected in type 1 autoimmune pancreatitis (AIP), salivary and lacrimal gland lesions, retroperitoneal fibrosis, nephritis, and other areas of high activity, all reflective of pathological changes occurring in this condition. It is also anticipated that this imaging modality will be a useful approach to the assessment of responses to treatment. Although there are still few systematic reports on PET examinations in IgG4-RD, we outline here some representative cases in which it was found useful, and consider its role in this disease.

Efficacy and Limitations of F-18-fluoro-2-deoxy-D-glucose Positron Emission Tomography to Differentiate Between Malignant and Benign Bone and Soft Tissue Tumors

Background/Aim: Positron emission tomography (PET) using 18fluorine-labelled fluorodeoxyglucose (FDG), is the most widely applied molecular imaging technique in oncology. The present study assessed the efficacy and limitations of FDG-PET by comparing FDG accumulation in bone and soft tissue lesions, as well as histopathological features. Patients and Methods: The study included 122 patients with 165 lesions, as assessed by histopathological examinations. The maximum standardized uptake values (SUVmax) of benign lesions were compared to those of primary, recurrent, or metastatic sarcomas, as well as those of other malignancies. Results: The sensitivity, specificity, and accuracy of SUVmax for differentiation between benign lesions and primary sarcomas were 67.9%, 92.9%, and 80.4%, respectively. There were no significant differences between benign lesions and recurrent or metastatic sarcomas. Conclusion: Although FDG-PET is a useful imaging modality to differentiate primary sarcomas from benign lesions, it is difficult to differentiate residual or metastatic sarcomas from benign lesions.

Cardiac Time-of-flight PET for Evaluating Myocardial Perfusion with 13 N-ammonia: Phantom Studies for Estimation of Defect and Heterogeneity

Background: Cardiac 13 N-ammonia ( 13 N-NH3) positron emission tomography (PET) is approved by Japanese Ministry of Health, Labour and Welfare for diagnosis of ischemic heart disease. New PET camera recently has three-dimensionalmode acquisition and ordered subset expectation maximization (OSEM) reconstruction with time-of-flight (TOF) and point spread function (PSF) correction technology. The aim of the phantom study was to evaluate the usefulness of this novel technology using 13 N-NH3 and 18 F-fluorodeoxyglucose ( 18 F-FDG). Method: PET imaging was performed using a lung-heart torso phantom with myocardial perfusion defects. The indices of defect contrast, the coefficient of variation (CV) and the index of homogeneity were analyzed by using four reconstruction schemes, including OSEM, OSEM+TOF, OSEM+PSF, and TOF+PSF correction methods. Results: The phantom study showed that TOF resulted in improvements of defect lesion detectability with low statisticalnoise. The defect contrast index of TOF +PSF was significantly larger than that of OSEM only (p= 0.048). The cardiac percent root mean square uncertainty (RMSU) with PSF was 25.9 %i n OSEM+PSF and 20.9 %i n TOF+PSF. In contrast cardiac % RMSU without PSF correction was 14.8% in OSEM and 15.3 %i n TOF, which was lower than that with PSF correction. The average wall counts were homogeneous in four reconstruction methods in 13 N-NH3. The value of % CV on the profile curve of 13 N-NH3 images was confirmed to be smaller than 5% in all reconstruction methods. Conclusions: The new PET technology with TOF and PSF correction may extend the possibility of precise analysis of abnormal perfusion defects, and clinical applications are expected.