MR imaging of brainstem hemorrhage.

To determine the chronologic changes in the MR appearance of brainstem hemorrhage and to evaluate the clinical efficacy of MR imaging, 15 patients were examined with a 0.5-T MR scanner with inversion-recovery (IR) and T2-weighted spin-echo (SE) images. In the acute stage (up to the sixth day), hematomas were hypo- or isointense on IR images and isointense and then hypointense on SE images. In the subacute stages (the seventh day to 2 months), hematomas changed from hypo- or isointensity to hyperintensity centripetally on IR images and to hyperintensity on SE images. Parenchymal reactions were hypointense first on SE images and then on IR images. In the chronic stage (over 2 months), hematomas "disappeared" and the parenchyma was hypointense on both IR and SE images. The superior clinical efficacy of MR imaging relative to CT for the detection of hemorrhage was obvious except in the acute stage, when hematomas had an intensity similar to that of the adjacent brainstem, and the patients usually were in serious condition.