Biomedical subjects
Publications and source records attributed to I Shirouzu.
The authors present a case of neurinoma of the oculomotor nerve without evidence of von Recklinghausen disease. The literature is reviewed and CT and magnetic resonance findings are discussed.
The authors present a case of hypertensive encephalopathy in which CT and MR were performed. The brain stem and cerebellum were revealed as low density areas on CT and high intensity areas on T2-weighted MR images with mass effect. Slight abnormality was also noticed in the deep cerebral white matter. This distribution pattern is contrary to that described in previous reports in which cerebral white matter was mainly involved. The lesions showed definite improvement when the blood pressure was normalized. MR is more sensitive than CT, and is useful for early detection of the abnormality and follow-up study.
To evaluate the potential of superselective cavernous sinus (CS) sampling in patients with functioning pituitary adenomas, we performed direct CS sampling in 18 patients with Cushing syndrome and other functioning adenomas using a mini-catheter. Samples from the inferior petrosal sinuses (IPS) were also obtained. All of the samples from 20 CS of 10 patients with Cushing syndrome and 13 of 16 samples from CS of eight patients with other adenomas were successfully obtained. No complication occurred. In three patients, the mini-catheter was introduced to the contralateral CS through intercavernous communication, and bilateral sampling could be performed via the unilateral jugular vein. The CS/peripheral (CS/P) ratio of ACTH (mean = 66.1) was significantly greater than the IPS/peripheral (IPS/P) ratio (mean = 14.9) in Cushing disease. In other functioning adenomas, the CS/P ratio (15.8) was not significantly higher than the IPS/P ratio (4.8). Direct CS sampling offers a much higher CS/P ratio than IPS/P ratio in Cushing disease, and may provide sufficient diagnostic accuracy without CRH stimulation or bilateral simultaneous sampling.
We studied 76 patients with cerebral arteriovenous malformations (AVMs) using dynamic-CT with intravenous injection of contrast material and reconstructed three-dimensional images (3D-CT angiography). All patients received stereotactic radiotherapy (gamma-knife). We compared 3D-CT angiography with conventional angiography to determine the usefulness of this technique. 3D-CT angiography could be performed in conjunction with usual axial high-resolution CT without any additional scanning time and within 10-30 minutes for the overall study. Most niduses and drainers of AVMs were clearly visualized by 3D-CT angiography. 3D-reconstruction was very helpful in demonstrating the niduses, drainers, and three-dimensional structure of AVMs. Demonstrations of feeders were not remarkable. Dynamic CT was very helpful in dose planning for gamma-knife radiosurgery, because gamma-knife angiograms were limited in terms of angles, magnification, and establishing precise localizations using a head frame. 3D-CT added information on trails of drainers and was useful in reducing the volume of irradiation. 3D-CT angiography of cerebral AVMs could be performed routinely, and three-dimensional imaging was helpful in demonstrating the complex anatomy of cerebral AVMs. This technique was very helpful in planning gamma-knife radiosurgery.
The purpose of this study was to compare Turbo-FLAIR imaging, T2-weighted imaging, and double-dose gadolinium-enhanced MR imaging in the detection of brain metastasis. Using the three sequences, 20 consecutive patients with brain metastases were prospectively studied with a 1.5-Tesla system. Three independent, blinded readers assessed the images for the presence, size, number, and location of metastatic lesions. In the detection of large lesions (> 0.5 cm), Turbo-FLAIR imaging (38/48, 79%) was not significantly different from gadolinium-enhanced imaging (42/48, 88%) (p = 0.273). T2-weighted imaging (31/48, 65%), however, was inferior to gadolinium-enhanced imaging (p < 0.05). There was no difference between Turbo-FLAIR imaging and gadolinium-enhanced imaging in the accuracy of detecting solitary brain metastasis (4/4, 100%). In conclusion, Turbo-FLAIR imaging is a useful, noninvasive screening modality for brain metastasis. Its use may lead to cost savings in the diagnosis of brain metastases and may impact positively the cost-effectiveness of treatment.