Radiation Dose Reduction without Compromise to Image Quality by Alterations of Filtration and Focal Spot Size in Cerebral Angiography

OBJECTIVE: Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. MATERIALS AND METHODS: Radiation dose and image quality were analyzed by varying the filtration and focal spot size on digital subtraction angiography exposure protocols (1, inherent filtration + large focus; 2, inherent + small; 3, copper + large; 4, copper + small). For the in-vitro analysis, a phantom was used for comparison of radiation dose. For the in-vivo analysis, bilateral paired injections, and patient cohort groups were compared for radiation dose and image quality. Image quality analysis was performed in terms of contrast, sharpness, noise, and overall quality. RESULTS: In the in-vitro analysis, the mean air kerma (AK) and dose area product (DAP)/frame were significantly lower with added copper filtration (protocols 3 and 4). In the in-vivo bilateral paired injections, AK and DAP/frame were significantly lower with filtration, without significant difference in image quality. The patient cohort groups with added filtration (protocols 3 and 4) showed significant reduction of total AK and DAP/patient without compromise to the image quality. Variations in focal spot size showed no significant differences in radiation dose and image quality. CONCLUSION: Addition of filtration for angiographic exposure studies can result in significant total radiation dose reduction without loss of image quality. Focal spot size does not influence radiation dose and image quality. The routine angiographic protocol should be judiciously investigated and implemented.

Lesions in the splenium of the corpus callosum: Clinical and radiological implications

Background: Brain MRI may unexpectedly display abnormalities in splenium of the corpus callosum (SCC). However, the clinical implications of this lesion are unclear and are not always consistent with ischemic infarctions. We performed this study to clarify the clinical and radiological implications in patients with SCC lesions. Methods: We retrospectively reviewed consecutive patients with MRIreported SCC changes between 2009 and 2012. We analyzed clinical and radiological findings, etiologies, cognitive impairment, and clinical outcomes. Results: We found 30 patients (16 females; mean 50.5 years) who had SCC lesions on MRI. Confusion was the most common clinical finding in 50% of cases. Cerebral infarction was the most common etiology (50%). The most consistent SCC changes on MRI were low signal in T1WI, high signal on T2WI and FLAIR, and high signal on DWI. We classified SCC lesions into in situ SCC lesions (SCC only) and multiple (SCC plus) lesions for patients with multiple lesions. The clinical symptoms of SCC only lesions were relatively mild. Cognitive functions were evaluated by Mini Mental State Examination (MMSE) and clinical dementia rating (CDR) scale at the time of discharge and patients with SCC only lesions showed less impaired cognition compared with those with SCC plus lesions. Clinical outcomes were evaluated by the modified Rankin scale at 1 month and patients with SCC only lesions revealed good clinical outcomes compared with those with SCC plus lesions. Conclusions: MRI-reported SCC lesions may have heterogeneous etiologies and present with various symptoms. The clinical course and outcome are relatively good, particularly in small isolated and oval shaped SCC lesions.

Early MRI Findings in a Patient With Klebsiella Pneumoniae Cerebritis

No abstract available.

Trigeminal Neuralgia due to Pontine Infarction

No abstract available.

Development of a sandwich ELISA for the detection of Listeria spp. using specific flagella antibodies

Five monoclonal antibodies (MAbs) and chicken immunoglobulin (IgY) were developed by immunizing with flagella purified from Listeria monocytogenes 4b and the five MAbs have been confirmed to be specific against three different epitopes of flagellin. The antibodies showed specific reaction to Listeria genus and no cross-reactivity with other bacteria tested in this experiment including E.coli O157:H7 and Salmonella enteritidis. Sandwich enzyme-linked immunosorbent assays (ELISA) using the MAbs and IgY were developed to detect Listeria species and the sensitivity and specificity of the developed ELISA have been analyzed. The detection limit of ELISA using MAb 2B1 and HRP labeled IgY was 1 x105cells/0.1 ml at 22degrees C and 1x106 cells/0.1 ml at 30degrees C. ELISA using the pair of MAbs (MAbs 2B1 and HRP labeled MAbs 7A3) detected up to 104cells/0.1 ml at 22degrees C and 30degrees C. Detection limit of sandwich ELISA using IgY was 10 times lower than MAb pair. Using the developed ELISA, we could detect several Listeria contaminated in food samples after 48 h-culturing. In conclusion, both MAbs and IgY have been proved to be highly specific to detect Listeria flagella and the developed sandwich ELISA using these antibodies would be useful tool for screening Listeria spp. in food.