Teaching Case

Stroke one year prior to MRI examination.

The patient had a history of stroke one year ago. He was referred to follow-up MRI. T1-and T2-weighted images, FLAIR (fluid attenuated inversion recovery) images were obtained. The left middle cerebral artery appeared to be narrowed, therefore, in the same session MR angiography with 3D-PC (phase contrast), and 3D-TOF (time-of-flight) was performed. Also, echo-planar diffusion imaging was obtained.

Fibromuscular dysplasia is vasculopathy frequently involving the renal arteries. Intimal and medial proliferative changes in the arteries, result in characteristic 'string of beads' appearance, or segmental narrowing. Internal carotid arteries, and vertebral arteries can be involved with relatively common bilateral lesions. Common carotid bifurcation, and proximal internal carotid artery are usually spared. In the current patient, involvement of the left middle cerebral artery was isolated, as no other vascular lesion was found on a digital subtraction angiographic study. Main complications of fibromuscular dysplasia include dissection, aneurysm rupture, and emboli. In the current patient, an area of macrocystic encephalomalacia was noted in the left insular region on FLAIR, and diffusion images, probably due to an embolus.