Case report. MRI and MR angiography of basilar artery dissection in a child.

MRI showed a pontine infarct and mural thickening of intermediate signal in T1-weighted images proximal to occlusion of the basilar artery in a 10-year-old boy. Two days later the mural thickening was of high signal, consistent with methaemoglobin formation and MR angiography (MRA) showed nonspecific lack of flow in the mid-segment of the basilar artery, which corresponded to a tapered occlusion at arteriography. MRI is more useful than MRA for noninvasive diagnosis of basilar artery dissection.