Impact of MRA Echo Time on Stroke Prevention Therapy in Pediatric Patients with Sickle Cell Disease

Background: Flow artifact, intrinsic to Magnetic Resonance Angiography (MRA), is dependent on technical parameters and can lead to overinterpretation of stenosis. Degree of cerebrovascular stenosis in pediatric patients with sickle cell anemia (SCA) informs need for chronic transfusion therapy, which may have significant risks. The primary objective of this study was to document any change in stroke prevention therapy that could be attributed to the implementation of a standardized MRA scanning protocol. Procedure: A standardized MRA scanning protocol with an echo time of <5 msec was implemented at Montefiore Medical Center in May 2016. Retrospective chart review identified 29 patients ≤ 21 years with SCA cerebral vasculopathy and an MRA head pre- and post-May 2016. Level of arterial stenosis on MRA, echo time, and treatment plans were documented both pre- and post-implementation. McNemar analysis determined the significance of change in treatment plans before and after implementation of the standardized scanning protocol. Results: Previously seen stenosis was re-classified to a lower degree in 12/29 patients (41%). Notably, 6 patients had a reclassification of vasculopathy leading to discontinuation of chronic transfusion therapy whereas 0 patients required escalation of therapy to chronic transfusions. McNemar analysis showed this difference to be statistically significant (p = 0.042). Conclusion: Minimizing flow artifact with echo time <5msec improves accurate interpretation of true cerebrovascular disease and ensures appropriate treatment plans are in place for stroke prevention. This is especially important when trying to implement “TCD With Transfusions Changing to Hydroxyurea (TWiTCH)” clinical trial results in the real-world setting.