A 10-year-old boy with sickle cell disease and history of acute chest syndrome now presents with pain crisis. MRI of the brain was requested for episodic slurred speech. Axial FLAIR MR image (left) and DWI (middle) illustrate many of the manifestations of SCD in the brain. The arrowheads on the FLAIR image point out areas of old (silent) infarctions in the white matter of the centrum semiovale on the right and at the posterior aspect of the left superior frontal gyrus. The DWI shows an additional area of signal abnormality in the anterior aspect of the right superior frontal gyrus, representing a recent infarction. In addition, there is atrophy of the left cerebral hemisphere, which is seen in the setting of sickle cell–associated vasculopathy manifest by nonvisualization of the left middle cerebral artery by MRA (arrows on the right image). The MRA also shows subtle collaterals (moyamoya vessels) in the lenticulostriate distribution on the left (arrowhead).