ABNORMAL CRANIAL MAGNETIC-RESONANCE-IMAGING SCANS IN SICKLE-CELL DISEASE - NEUROLOGICAL CORRELATES AND CLINICAL IMPLICATIONS

Objective.-Eight asymptomatic patients with sickle-cell disease (SCD) with magnetic resonance imaging (MRI) abnormalities consistent with ce rebral infarcts (group 1) and eight asymptomatic patients with SCD wit h normal MRI scans (group 2) were followed up to assess the neurologic al correlates and the clinical outcome. Design.-Patients in the two co horts underwent clinical evaluations and xenon 133 regional cerebral b lood flow (rCBF) studies within 1 month of the entry MRI. This study s equence was repeated up to 5 years later. Neuropsychological studies a lso were performed in six group 1 patients and eight group 2 patients at the end of the study. Setting.-The patients were recruited from the Comprehensive Sickle Cell Center at Columbia University, New York, NY . Patients.-All patients had SCD, hemoglobin SS, and normal findings o n clinical evaluation at entry. The group 1 cohort had clinically sile nt MRI abnormalities consistent with cerebral infarction. The group 2 cohort was age matched to group 1 and had normal MRI studies. Interven tions.-None. Main Outcome Measure.-The natural history of MRI abnormal ities and the neurological correlates were assessed to determine the p redictive value of subclinical MRI lesions as a risk factor for clinic ally apparent stroke. Results.-The mean duration of MRI follow-up was 3.7 years. In group 1, four patients (50%) demonstrated progressive MR I abnormalities and three patients (38%) became clinically symptomatic . In group 2, findings for all patients remained normal on clinical an d radiological examination. Both groups had markedly elevated rCBF val ues. Individual rCBF differences correlated with the specific MRI abno rmalities. The psychometric study results were similar in the two coho rts. Eighty-three percent of group 1 and 88% of group 2 patients had d efective scores in one or more areas of cognitive functioning. Three p atients met cognitive criteria for dementia. Conclusions.-Cranial MRI abnormalities have important prognostic implications even when detecte d in clinically asymptomatic patients. Cognitive abnormalities exist i n patients with SCD even in the absence of MRI abnormalities or clinic al stroke.