MR imaging of brainstem tumors.

Eighteen patients aged 4-72 years old with brainstem tumors were studied using a 0.5 T magnetic resonance (MR) imager and a third- or fourth-generation computed tomographic (CT) scanner. MR imaging showed the brainstem to be enlarged on sagittal views in all cases; exophytic growth was seen in eight. Alterations of signal intensities were shown in most cases on spin-echo sequences using 30 and 90 msec echo times and inversion recovery techniques. It was not possible to distinguish primary from metastatic tumors. The configurations and margins of the areas with abnormal signal did not appear to correlate with the clinical behavior of the tumors. CT was able to recognize brainstem tumor in only 13 of 16 cases. In the two cases of metastases, plain CT scans were normal, but enhancement was seen after administration of contrast material in one. It appears that MR imaging is sensitive in detecting tumor enlargement and abnormal signals and is superior to CT in evaluating brainstem tumors.