Abstract WMP119: An MRI Surveillance Protocol for Pediatric Sickle Cell Anemia

Abstract

Background: Sickle cell anemia (SCA) is a leading cause of stroke and neurologic disability in children. In the 20 years since the publication of the STOP trial, chronic transfusion therapy and hydroxyurea have shown efficacy as disease-modifying therapies, especially by improvement of transcranial Doppler (TCD) velocities and reduction in the incidence of overt stroke. Despite the publication of the SIT Trial 2014, screening for silent stroke is not universally implemented. Here we report our center’s experience with screening neuroimaging in young children with SCA. Methods: This is a single center, retrospective case series of patients with SCA (HbSS and HbSb 0 -thalassemia) managed in a comprehensive sickle cell center. Patients undergo TCD screening per STOP guidelines beginning at age 24 months. Screening MRI/MRA brain are also recommended at 5, 10, 15, and 20 years of age. Imaging data for the children 5-9 years of age are reported. Results: There were 39 subjects within the defined age range, 37 of whom were receiving disease-modifying therapy (hydroxyurea, N=34; chronic transfusions, N=3). Mean age of initiation of disease-modifying therapy was 4.2 years. MRI/MRA of the brain was obtained according to our screening protocol in only 21 (54%), indicating incomplete screening and opportunity for quality improvement. Indeed, most MRIs were obtained for a clinical concern and/or a non-normal TCD (85%). Abnormal parenchyma and/or vasculature was identified in 11 of 21 (52%) imaged subjects. In patients imaged before starting disease modifying therapy, 2 of 9 had stroke (22%). In patients imaged after starting disease modifying therapy, 7 of 12 had stroke and or arteriopathy (58%). Conclusions: Over half (52%) of young children (5-9 years) with SCA in our center who had an MRI/MRA had abnormal findings, indicating a high yield for potentially actionable results. This may be an under-estimate of CNS disease burden, because 46% of the population did not undergo screening MRI/MRA. Proactive screening for cerebrovascular complications in SCA may allow early intervention that further improves patient outcomes.