New research has found that magnetic resonance angiography (MRA) can improve the interpretation of cerebrovascular disease in pediatric patients with sickle cell disease (SCD) and help create appropriate stroke prevention treatment plans.

It is also important when implementing the results from the “TCD With Transfusions Changing to Hydroxyurea (TWiTCH)” clinical trial in a real-world setting.

In MRA, which is routinely performed in these children to evaluate intravascular abnormalities, flow artifacts are commonly encountered and can lead to the overinterpretation of stenosis.

Current recommendations, which are based on the multicenter, randomized, controlled TCD (transcranial Doppler) with Transfusions Changing to Hydroxyurea (TWiTCH) trial recommend that children 2 to 16 years of age with normal or abnormal TCD results who have been receiving transfusion therapy for 1 year or more can be transitioned off transfusions and on to hydroxyurea if they have low-risk MRA imaging.

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In May 2016, an optimized MRA scanning protocol with an echo time of less than 5 ms, which was based on the Stroke with Transfusions Changing to Hydroxyurea (SWiTCH) protocol, was implemented at Montefiore Medical Center in New York City. Level of arterial stenosis on MRA, machine parameters, and treatment recommendations were compared both prior to and following implementation of the protocol in all patients.

The researchers sought to document any changes in stroke prevention therapy that might be attributed to implementation of the standardized MRA protocol in patients with SCD. A retrospective chart review was conducted among patients with SCD at Montefiore Medical Center. Results of the analysis were published in the journal Pediatric Blood & Cancer.

Twenty-one pediatric patients with SCD were identified who had received a head MRA before and after initiation of the study. Overall, 10 of the 21 patients fulfilled study inclusion criteria.

With use of the protocol, previously observed stenosis was reclassified to a lower degree in 6 of the 10 patients, which was associated with the discontinuation of transfusions in 5 of the 6. None of the participants required escalation of therapy to chronic transfusions.

Accurate diagnosis of large vessel narrowing has clinical implications for the classification of stroke risk, as well as for the initiation and escalation of clinical interventions, including transfusions and surgical procedures in children with SCD.

The authors concluded that use of their strategy in pediatric patients with SCD can help improve accurate interpretation of cerebrovascular disease and stroke prevention. “This is especially important for implementing . . . TWiTCH . . . clinical trial results in the real-world setting.”


Strumph K, Morrone K, Dhillon P, et al. Impact of magnetic resonance angiography parameters on stroke prevention therapy in pediatric patients with sickle cell anemia. Pediatr Blood Cancer. Published online November 28, 2022. doi:10.1002/pbc.30109