Primary intracranial tumor imaging: a comparison of magnetic resonance and CT.

Abstract

Patients (26) with primary intracranial tumors were evaluated by magnetic resonance (MR) and a comparison was made with CT [computed tomography] findings. The SE [spin echo] technique with TR [interval between successive radio-frequency pulses] = 2000 ms and TE [interval between the initial excitatory pulse and 2 subsequent sampling pulses] = 56 ms was most useful in delineating normal anatomy, in differentiating gray and white matter and in optimizing the visualization of edema. The use of TR = 500 ms optimized sensitivity to T1 relaxation time differences in disparate tissue and best defined the CSF spaces. Although prolongation of T1 and T2 relaxation values was seen with most malignant lesions, several cases produced no obvious prolongation of T1. Separation of tumor from surrounding edema was possible in several instances. In 16/26 patients, information not available on CT was obtained with MR. This included detection of altered tissue characteristics where CT showed only mass effect, more accurate depiction of full extent and location of tumor and visualization of associated abormalities. A small inner ear epidermoid tumor seen with high-resolution CT (1.5-mm sections) was difficult to identify with certainty on MR and in 2 other cases punctate foci of calcification were not identified on MR.