Volumetric, CBF, and OEF analysis in SCA participants and control volunteers. Controls (n = 11), SCA participants not on blood transfusion and without a history of prior overt stroke (n = 27) and SCA participants on blood transfusion (n = 7) are shown, however to reduce confounds from patient heterogeneity only non-transfusion patients were used for testing the primary hypothesis of the study. Tissue volumes (A) are significantly reduced in non-transfusion patients versus control volunteers. CBF (B) is elevated (P < 0.05) in the cortical mask (Fig. 3) of non-transfusion patient versus controls and did not differ significantly between flow territories. OEF (C) is also elevated (P < 0.05) in non-transfusion patients relative to controls. The central black line on the box plot depicts the median of the data, top and bottom solid lines depict 25th and 75th percentile of the data, and whiskers extend to all data points not determined to be outliers. Actual data points are overlaid on boxplots as red circles (black circles for outliers).