MRA of the intracranial circulation in asymptomatic @entity1 with XXXX .

@entity1 @entity1188 @entity3458 @entity75
BACKGROUND: MR angiography (MRA) provides a mechanism for non-invasively studying blood flow, thus providing a new opportunity to study the intracranial circulation in asymptomatic @entity3458 ( @entity3458 ) @entity1 . Although conventional angiography is the gold standard for the depiction of vascular anatomy, this is too invasive for an asymptomatic population. OBJECTIVE: To establish the range of appearances in asymptomatic @entity3458 @entity1 and to correlate brain MRI results (either sub-clinical @entity75 ) with the MRA findings. MATERIALS AND METHODS: Brain MRI and MRA of the intracranial circulation was performed on 22 @entity1 (13 male and 9 female, median age 7.5 years, range 1.3-20 years). Fourteen were homozygous SS and eight were SC. The median haematocrit at the time of MRI was 25.9 (range 13.8-33.3). RESULTS: On MR imaging, four @entity1 had @entity1188 in eight vascular territories (six anterior and two posterior). In 3/4 of anterior vascular territories with @entity1188 , long ( >/= 6 mm) segments of abnormal signal were seen at the internal carotid artery bifurcation with associated reduced distal flow. Short focal areas of abnormal signal were commonly seen where vessels branched, bifurcated or curved and were not associated with @entity1188 . These areas probably represent turbulence-related dephasing secondary to high velocity flow found in @entity3458 . CONCLUSION: Long segments ( >/= 6 mm) of abnormal signal with reduced distal flow correlated with sub-clinical @entity1188 .
