Biomedical subjects
Publications and source records attributed to S Nakasu.
A cavernous angioma with the unusual CT features of a large cyst and a small nodule was found in an 8-month-old girl. The cyst contained crystal-clear fluid, and a previous hemorrhagic event was histologically confirmed.
A case of lateral intrathoracic meningocele incidentally found in association with neurofibromatosis Type 1 is presented. Magnetic resonance imaging proved most valuable in diagnosis.
We report a case of metastatic adenocarcinoma to the brain that appeared as a homogeneously hyperdense mass on CT. The lesion was initially diagnosed as an intracerebral hematoma. On serial CT scans, the high density lesion progressively enlarged. Pathology showed coagulation necrosis without hemorrhage or calcification. Analysis of the tumor revealed elevation of the protein content relative to the normal brain. We conclude that the high CT attenuation was due to the elevated protein content.
PURPOSE: To investigate the early changes in diffusion-weighted MR images in the sustained limbic seizures. METHOD: Intraperitoneal injection of kainic acid was used to induce sustained limbic seizures in seven rats. The animals were investigated with serial 2.0-T MR imaging beginning immediately after kainic acid-induced seizures, and at 24 hours, 3 days, and 7 days after the kainic acid injection. Diffusion-weighted spin-echo and T2-weighted images and apparent diffusion coefficients were sequentially assessed and compared with histologic changes. The results were compared with eight control animals given buffered saline intraperitoneally. RESULTS: Diffusion-weighted MR images revealed an increase in signal intensity bilaterally in the amygdala and the piriform cortices immediately after the sustained seizures, whereas T2-weighted images did not show changes in signal intensity at this time. Both diffusion-weighted and T2-weighted images showed marked increase in signal intensities in these same areas 24 hours after kainic acid injection. The apparent diffusion coefficient values were significantly lower in the area of the amygdala and the piriform cortex immediately after and lower again 24 hours after the sustained seizures. The area of hyperintensity in diffusion-weighted images was concordant with the histologic distribution of neuronal pyknosis and neuropile vacuolation. CONCLUSION: Diffusion-weighted MR revealed focal abnormalities in the limbic system after 1 hour of sustained seizures induced with kainic acid, before changes on T2-weighted imaging. Diffusion-weighted MR is a potential method for studying the mechanisms of brain damage caused by sustained seizures.