Interesting CT findings of brain-stem infarction

The present authors have recently experienced two cases of brain-stem infarction in which periodic CT showed positive contrast enhancement in a course similar to supratentorial infarction. Case 1 was a 61-year-old female patient in whom a ring-positive finding of contrast enhancement was observed in the left pons on the 23rd morbid day. Case 2 was a 76-year-old male patient, in whom a positive finding of contrast enhancement was observed in the wide area ranging from the right thalamus and the right mesencephalon to the pons and the bilateral cerebellar hemispheres on the 20th morbid day. The mechanism of the manifestation of positive contrast enhancement in brain-stem infarction is considered to be similar to that of supratentorial infarction; that is, it occurs due to the extravascular leakage of contrast media from neogenetic blood vessels whose blood brain barrier is destroyed or absent. In addition, brainstem infarction was considered to be pathologically in good accordance with supratentorial infarction. (author)