Biomedical subjects
Publications and source records attributed to Hirotoshi Ito.
We report a 70-year-old woman with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by percutaneous transcatheter embolization with n-butyl cyanoacrylate and microcoils.
BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) is usually done before administration of intravenous contrast agents. Repetition of DWI is occasionally necessary after administration, but the effects of contrast material on DWI and apparent diffusion coefficient (ADC) values have not yet been fully examined. The present study assesses whether administration of gadolinium-based contrast material significantly affects DWI and ADC values. METHODS: We examined DWI data from 39 patients (mean age, 67.9 years; range, 34 to 87 years) who were evaluated with a stroke protocol at our institute. All patients were scanned at the acute or subacute stages of infarct from 3 hours to 5 days after symptom onset. We obtained DWI images using single-shot echo-planar imaging with a b value of 1000 s/mm2. Patients were injected with 0.1 mmol gadopentetate dimeglumine per 1 kg body weight. We examined the signal-to-noise ratio of the normal brain and the infarct and evaluated the contrast-to-noise ratio of each lesion. In addition, we compared the ADC values calculated from the DWI images before and after administration of contrast. The statistical significance of differences between precontrast and postcontrast administration was determined by use of a paired t test. RESULTS: The signal-to-noise and contrast-to-noise ratios of the DW images were not significantly different before and after administration of contrast agent. The ADC values were slightly lower after administration of contrast agent for both normal brain (P=0.0011) and infarcts (P=0.038). The estimated differences in the ADC values were approximately 1.3% and 3.5% for normal brain and infarcts, respectively. CONCLUSIONS: The lack of a significant difference between the signal-to-noise and contrast-to-noise ratios of DW images before and after administration of contrast agent indicates the feasibility of postcontrast DWI.
OBJECTIVE: The purpose of this study was to investigate the ability of high-resolution computed tomography (CT) images to distinguish between benign and malignant vertebral compression fractures. METHODS: Computed tomography images of 45 benign compression fractures in 40 patients and 33 malignant compression fractures in 33 patients were evaluated. A 16-slice multidetector-row CT scanner was used for data acquisition, and axial images with a slice thickness of 1 mm and sagittal and coronal multiplanar reconstruction images with a slice thickness of 0.7 to 1 mm were used for interpretation. RESULTS: The following findings were significantly more frequent in malignant fractures: destruction of the anterolateral and/or posterior cortex of the vertebral body, destruction of the cancellous bone of the vertebral body, destruction of the end plate, destruction of the pedicle, a paraspinal soft tissue mass, and an epidural mass. The extremely reliable signs of malignancy were destruction of the anterolateral and/or posterior cortex of vertebral body (100% accuracy) and destruction of the cancellous bone of the vertebral body (97.4% accuracy). CONCLUSION: High-resolution CT can provide many useful signs for differentiating between benign and malignant vertebral compression fractures, and its diagnostic ability is sufficient for clinical use.