Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14 days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4 days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.

[Investigation of Computed Tomography Exposure Dose for Whole-body 18F-FDG PET/CT Examination in Chugoku-Shikoku Regions].

PURPOSE: We investigated the way of thinking about the CT dose setting, the exposure dose (CTDIvol, DLP) and the image quality (standard deviation of liver: SDliver) of whole-body PET/CT examinations in the Chugoku and Shikoku regions for the optimized CT dose setting. METHOD: It was researched in the target 29 facilities which is equipped with 18F-FDG, PET/CT scanner in that regions. We examined how to determine the dose of complete physical PET/CT setting, the CT radiation dose (CTDIvol and DLP) and the image quality of CT fusion image that is the standard deviation of liver CT value in each facility. RESULT: The optimized CT dose was lower than the diagnostic CT in many facilities. The 75th percentile CTDIvol was 6.01 mGy. The 75th percentile DLP was 560.9 mGy ×cm. The SDliver was 14.6±5.3 HU. CONCLUSION: The CT condition was low setting in comparison with diagnostic CT in many facilities. The exposure dose was lower than the diagnostic CT dose. The image quality of the normal region of liver was very close to the diagnostic CT. Even though it was low dose, images were less noise components.

[Differentiation between Hepatic Focal Lesions and Heterogenous Physiological Accumulations by Early Delayed Scanning in 18F-FDG PET/CT Examination].

PURPOSE: We examined whether early delayed scanning is useful for differentiation of liver lesion and heterogenous physiological accumulation in positron emission tomography (PET) examination. METHODS: The subjects of the study were 33 patients with colorectal cancer who underwent PET examination and were added early delayed scanning to distinguish between liver lesions and heterogenous physiological accumulation to conventional early images. We placed same regions of interest (ROI) in the tumor and hepatic parenchyma for early delayed and conventional early images. Then, we measured SUVmax of the ROIs and calculated tumor to liver parenchyma uptake ratio (TLR). In addition, change rates between early and early delayed images were calculated for the SUVmax and TLR. RESULTS: The receiver operating characterstic (ROC) analysis result of SUVmax showed the highest SUVmax change rate, and the ROC analysis result of TLR showed the highest early delayed scanning. The SUVmax of the lesions did not change between early scan and early delayed scanning (p=0.98), but it decreased significantly in the normal group (p<0.001). TLR of the lesion group was significantly increased (p<0.001) in early delayed images compared to early scan and TLR significantly decreased in the normal group (p<0.001). The AUC of the ROC curve showed the highest SUVmax change rate (0.99). CONCLUSION: Early delayed scanning could distinguish between liver lesions and heterogenous physiological accumulation in colon cancer patients.

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.