不顕性難治性部分てんかん患者の術前評価におけるPETの診断能 : 統計画像解析を用いた18F-FDG、11C-フルマゼニル、11C-フルマゼニル結合能画像の比較

広島大学(Hiroshima University)博士(医学)Doctor of Philosophy in Medical Sciencedoctora

Do Siberian Flying Squirrels reuse nest materials made by other individuals?

Arboreal small mammals nesting in tree hollows usually line nests with materials such as leaves and shredded bark. Pteromys volans orii (Siberian flying squirrel), an endemic subspecies to Hokkaido, Japan, uses shredded bark. Since their nest materials have a very consistent shape, we suspect the squirrels use much effort to collect and shred the bark. To save effort, they may reuse nest materials made by other individuals. To test this, we mixed artificial nest materials (coloured cotton strings) into nest materials and observed the transfer of strings among nests. Of 39 nest boxes seeded with coloured cotton strings, number of strings decreased in 25 boxes (64.10%). Strings from 12 boxes were moved to other boxes. In addition, we found that P. volans orii possibly reused nest materials prepared by other individuals. Both nests and nest materials may be important re-useable resources for P. volans orii

Diagnostic Performance of Positron Emission Tomography for the Presurgical Evaluation of Patients with Non-lesional Intractable Partial Epilepsy : Comparison among 18F-FDG, 11C-Flumazenil, and 11C-Flumazenil Binding Potential Imaging Using Statistical Imaging Analysis

To compare the diagnostic performance of 18F-FDG PET, 11C-FMZ PET, and 11C-FMZ BP imaging for the evaluation of patients with intractable partial epilepsy whose MRI findings are normal by using statistical imaging analysis. Ten patients underwent comprehensive presurgical evaluation, including PET studies, to assess the epileptic foci. The extent of cortical resection was based on the results of intracranial video-electroencephalography (IVEEG) monitoring and brain mapping under stimulation. The images of 10 patients and 30 controls were spatially normalized to templates generated in-house by non-rigid registration and the standardized images of the patients and controls were statistically compared. Epileptic focus candidates were visualized on a color map of axial images of each template and the focus site was identified in candidates for lobar location. In patients with Engel I postoperative seizure outcomes we assessed the sensitivity and specificity of the imaging methods for lobar focus localization. We also compared the concordance scores of patients with Engel I and Engel II-IV postoperative seizures. The sensitivity and specificity for lobar focus localization on 18F-FDG PET scans was 90.0% and 84.8%, respectively; it was 30.0% and 81.4% for 11C-FMZ PET, 40.0% and 66.7% for 11C-FMZ BP images, and 100.0% and 51.4% for 18F-FDG PET/11C-FMZ PET/11C-FMZ BP images. In one patient the epileptic focus not detected on 18F-FDG PET scans was shown on 11C-FMZ BP images. In patients with Engel I post-treatment seizures the concordance scores were significantly higher for 18F-FDG PET than 11C-FMZ PET and 11C-FMZ BP images (p < 0.05). With respect to sensitivity and specificity, 18F-FDG PET was superior to 11C-FMZ PET and 11C-FMZ BP imaging. However, in some patients with normal MRI results, 11C-FMZ BP studies may complement 18F-FDG PET findings in efforts to identify the epileptogenic lobar regions

Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

Purpose: The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods: This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm × 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm × 16 or 0.5 mm × 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results: The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P <.0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P <.0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary ves sels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion: Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners

Effects of pharmacist intervention in Vancomycin treatment for patients with bacteremia due to Methicillin-resistant Staphylococcus aureus.

OBJECTIVE:We conducted a retrospective study based on composite endpoints for treatment failure to evaluate the effect of pharmacist-led VCM initial dose planning for Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia patients. METHODS:A retrospective cohort study was performed between pharmacist intervention and non-intervention groups. In this study, four types of failure were defined as the composite endpoint. When any one of the following failures occurred: 1) Death within 30 days from the start of VCM therapy, 2) Positive blood culture 7 days after the start of VCM therapy, 3) Change of VCM to another anti-MRSA agent, and 4) Development of nephrotoxicity, we considered that VCM treatment had failed. Survival time analysis was conducted with the Kaplan-Meier method and Cox's proportional hazard model that included seven predefined parameters: pharmacist intervention, age, sex, weight, baseline VCM trough concentration, Charlson Comorbidity Index (CCI), and Pitt Bacteremia score (PBS). The effect of pharmacist intervention was studied as the survival probability estimated from the period of time from the start of VCM administration to the earliest failure. RESULTS:The survival rate at 30 days after starting VCM therapy, at the end of follow-up, was 53.1 and 82.1% in the non-intervention and intervention groups, respectively. A significant survival time prolongation was noted in the intervention group (p = 0.011, log rank test). Among the seven parameters, only pharmacist intervention was significantly different and its hazard ratio was 0.26 (p = 0.014). The survival probability of the intervention group was higher than that of the non-intervention group for the time to each failure. In subgroup analyses, a significant difference was noted in male patients between the intervention and non-intervention groups (p = 0.005). Age was categorized into those under and over 65 years old. For those over 65 years old, a significant difference was shown between the groups (p = 0.018). CONCLUSION:To our knowledge, this is the first study to evaluate the failure of VCM treatment based on the composite endpoint. Pharmacist intervention through the initial VCM dose planning could maintain a balance between the efficacy and safety of VCM treatment and might avoid treatment failure for patients with MRSA bacteremia. Further investigations with large sample sizes are required to confirm our findings

Diffusion-weighted MR imaging of non-complicated hepatic cysts: Value of 3T computed diffusion-weighted imaging

Purpose: To investigate the utility of computed 3T diffusion-weighted imaging (c-DWI) for the diagnosis of non-complicated hepatic cysts with a focus on the T2 shine-through effect. Materials and methods: In 50 patients with non-complicated hepatic cysts we acquired one set of DWIs (b-value 0 and 1000 s/mm2) at 1.5T, and two sets at 3T (b-value 0 and 1000 s/mm2, TE 70 ms; b-value 0 and 600 s/mm2, TE 60 ms). We defined the original DWIs acquired with b = 1000 s/mm2 at 1.5T and 3T as “o-1.5T-1000” and “o-3T-1000”. c-DWIs were calculated with 3T DWI at b-values of 0 and 600 s/mm2. c-DWI with b = 1000 and 1500 s/mm2 were defined as “c-1000” and “c-1500”. Radiologists evaluated the signal intensity (SI) of the cysts using a 3-point score where 1 = not visible, 2 = discernible, and 3 = clearly visible. They calculated the contrast ratio (CR) between the cysts and the surrounding liver parenchyma on each DWIs and recorded the apparent diffusion coefficient (ADC) with a b-value = 0 and 1000 s/mm2 on 1.5T- and 3T DWIs. Results: Compared with o-1.5T-1000 DWI, the visual scores of all but the c-1500 DWIs were higher (p = 0.07 for c-1500- and p < 0.01 for the other DWIs). The CR at b = 1000 s/mm2 was higher on o-3T-1000- than on o-1.5T-1000- (p < 0.01) but not higher than on c-1500 DWIs (p = 0.96). The CR at b = 0 s/mm2 on 3T images with TE 70 ms was higher than on 1.5T images (p < 0.01). The ADC value was higher for 3T- than 1.5T images (p < 0.01). Conclusions: Non-complicated hepatic cysts showed higher SI on o-3T-1000- than o-1.5T-1000 DWIs due to the T2-shine through effect. This high SI was suppressed on c-1500 DWIs. Keywords: Diffusion-weighted imaging, Field strength, Computed diffusion-weighted imaging, Non-complicated hepatic cysts, T2 shine-through effec

Representative 3D MDCT images of the L3 vertebra obtained from a 71-year-old man after five dynamic CT scans and two transarterial chemoembolization procedures for hepatocellular carcinomas.

<p>An axial CT image of the liver shows a recurrence of hepatocellular carcinoma in S7 as a low density area compared to adjacent liver parenchyma(a), (black arrow). The 3D image of the L3 vertebra is shown (b). Tissue bone mineral density (76.8 mg/cm³) is normal for age. The image is cut in half along the longitudinal midline.</p