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