Comparison of CBF and OEF between CRTT and HSCT SCD participants and children in the control group. (A) CBF is elevated before HSCT, similar to CRTT participants, and declines to control values after HSCT. (B) OEF is elevated before HSCT, similar to CRTT participants, and declines to control values after HSCT. This change is greater than the OEF improvement seen after a scheduled transfusion among CRTT recipients. NS, not significant; WB, whole brain.