Reverse enhancement of hemorrhagic brain lesions on postcontrast MR: detection with digital image subtraction.

Purpose: To investigate the decrease in signal intensity on T1 - weighted MR images of some hemorrhagic intracranial lesions after administration of contrast material.

Methods: Postprocessing digital image subtraction was performed in 16 MR studies (13 patients) of lesions that showed hyperintensity on noncontrast T1-weighted images. Repetition time and echo time were identical for all precontrast and postcontrast studies.

MR findings in methanol intoxication.

We report the MR and CT findings with pathologic correlation in a case of severe methanol intoxication. There was bilateral hemorrhagic necrosis of the putamen and caudate nuclei and, in addition, extensive subcortical necrosis and symmetric bilateral necrosis of the pontine tegmentum and optic nerves, which may indicate poor prognosis.