Prospective brain imaging evaluation of children with sickle cell trait: initial observations.
OBJECTIVE
To determine whether sickle cell trait (hemoglobin AS) is associated with abnormalities in the brain of asymptomatic children.


METHODS
Magnetic resonance (MR) imaging and MR angiography were performed prospectively in 26 siblings (eight girls, 18 boys; mean age, 10.5 years) of patients with sickle cell disease. Two neuroradiologists, blinded as to whether a child had hemoglobin AS or AA, reviewed images obtained in siblings. With MR imaging, lacunae, loss of white matter volume, encephalomalacia, or leukoencephalopathy was identified. With MR angiography, arterial stenosis, occlusion, or tortuosity was identified. Images with definite or possible abnormalities were mixed with randomly selected images and were referred to a third neuroradiologist for a completely blinded review. In cases in which all neuroradiologists concurred, a score was assigned that indicated the sibling had an abnormality. MR angiographic findings were assigned a score for tortuosity with a new quantitative scale.


RESULTS
Among 26 siblings screened, 21 children had sickle cell trait. Among these 21 children, two had mild abnormalities at MR imaging (sample prevalence rate, 10% [95% CI: 1%, 29%]), and four had arterial tortuosity (sample prevalence rate, 19% [95% CI: 5%, 42%]). When children with sickle cell trait were compared with 31 control subjects without the trait, arterial tortuosity was significantly more common in children with sickle cell trait (P =.014). Among children with sickle cell trait, percentage of hemoglobin S was significantly greater in children who had tortuosity than percentage of hemoglobin S in children who had normal blood vessels at MR angiography (P <.03).


CONCLUSIONS
Findings suggest that greater percentage of hemoglobin S is associated with mild vasculopathy. This vasculopathy may explain some of the excess risk of stroke among African Americans.
Steen
R Grant
RG
Department of Diagnostic Imaging, St Jude Children's Research Hospital, 332 N Lauderdale St, Memphis, TN 38105-2794, USA. grant.steen@stjude.org
Hankins
Gisele M
GM
Xiong
Xiaoping
X
Wang
Winfred C
WC
Beil
Kenneth
K
Langston
James W
JW
Helton
Kathleen J
KJ
D000293:Adolescent; D001921:Brain; D002648:Child; D005260:Female; D006441:Hemoglobin A / Q000032:analysis; D006451:Hemoglobin, Sickle / Q000032:analysis; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D012805:Sickle Cell Trait / Q000175:diagnosis* / Q000235:genetics
D006451:Hemoglobin, Sickle; C028672:hemoglobin AA; C028671:hemoglobin AS; D006441:Hemoglobin A