Time-of-flight MR angiogram from a child with sickle cell anemia (SCA) and Moya-Moya.

Severe narrowing of the distal internal carotid arteries and proximal middle cerebral arteries (black arrows) is typical of the intracranial vasculopathy seen with SCA. Prominent lenticulostriate collateral vessels produce the Moya-Moya (“puff of smoke”) pattern seen above the stenoses.