The cerebral blood flow (CBF) of 25 patients with sickle cell cerebrovascular disease (SCCVD) was examined using a Xenon-CT flow mapping method. Brain CT and MR findings were correlated with those of the Xenon-CT flow studies. CBF defects on Xenon-CT correlated reasonably well with the areas of cortical infarctions on the MR images, but in 27% of the cases, flow defects were slightly larger than the areas of infarctions on the MR images. In deep watershed or basal ganglia infarctions, abnormal CBF was noted about the cerebral cortex near infarctions in 72% of the patients, regardless of infarction sizes on the MR images. However, decreased CBF was recognized in 4 of the 9 children whose MR images were virtually normal. Thus, the extent of flow depletion cannot be predicted accurately by MR imaging alone. Xenon-CT flow mapping proved a safe and reliable procedure for evaluation of the CBF of patients with SCCVD. Although this study is preliminary, it may have a potential in selecting patients for hypertransfusion therapy, as a noninvasive test and for following children with SCCVD during their therapy. Careful correlation of results of CBF with those of MR imaging or of CT is important for objective interpretations of flow mapping images.

Subarachnoid hemorrhage occurs in 1%-2% of patients with neurological complications from sickle cell disease. The authors report a case of subarachnoid hemorrhage in a 13-year-old black girl with sickle cell disease. Computed tomography of the brain demonstrated diffuse subarachnoid hemorrhage in the right sylvian fissure and the right frontoparietal cortical region. Angiography revealed no evidence of aneurysm but multiple stenosis and/or occlusions of the distal branches of the anterior and middle cerebral arteries bilaterally. Rupture of leptomeningeal collateral vessels is a possible cause of subarachnoid hemorrhage in our patient.