The use of CT scan and metrizamide CT cisternography for the diagnosis of brain stem glioma

10 cases of brain-stem glioma were analysed by conventional CT scan before and after various treatments. The density of each tumor was variable; in six patients tumors showed a low-density mass lesion, three had iso-density, and the high density in one patient. Mass signs, such as the displacement of the fourth ventricle and the obstruction of the pontine, an ambient, and a C-P angle cistern, were observed in most cases. Contrast enhancement was observed on the initial scan of three cases and appeared later on a follow-up CT scan during or after treatment in another three cases. Radiation and steroid administration changed the density pattern in four cases, which correlated well with clinical manifestations. Metrizamide, a non-ionic water-soluble contrast medium, was introduced into the subarachnoid space for CT cisternography in six cases. Metrizamide CT cisternography (MCTC) was accomplished in each case without any serious complications. MCTC could thus delineate the tumor mass more accurately than the conventional CT scan. In conclusion, the conventional CT scan and MCTC both offer definite advantages for the diagnosis and evaluation of brain-stem glioma and its therapeutically induced change. (author)