Magnetic resonance imaging/angiography and transcranial Doppler velocities in sickle cell anemia: Results from the SWiTCH trial

Kathleen J. Helton, Robert J. Adams, Karen L. Kesler, Alex Lockhart, Banu Aygun, Catherine Driscoll, Matthew M. Heeney, Sherron M. Jackson, Lakshmanan Krishnamurti, Scott T. Miller, Sharada A. Sarnaik, William H. Schultz, Russell E. Ware

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


The Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) trial compared standard (transfusions/chelation) to alternative (hydroxyurea/ phlebotomy) treatment to prevent recurrent stroke and manageiron overload in children chronically transfused over 7 years before enrollment. Standardized brain magnetic resonance imaging/magnetic resonance angiography (MRA) and transcranial Doppler (TCD) exams were performed at entry and exit, with a central blinded review. A novel MRA vasculopathy grading scale demonstrated frequent severe baseline left/right vessel stenosis (53%/41% Grade 4); 31% had no vessel stenosis on either side. Baseline parenchymal injury was prevalent (85%/79% subcortical, 53%/37%cortical, 50%/35%subcortical and cortical).Most children had low or uninterpretable baseline middle cerebral artery TCD velocities, which were associated with worse stenoses (incidence risk ratio [IRR] = 5.1, P ≤ .0001 and IRR = 4.1, P < .0001) than normal velocities; only 2% to 12% had any conditional/abnormal velocity. Patients with adjudicated stroke (7) and transient ischemic attacks (19 in 11 standard/8 alternative arm subjects) had substantial parenchymal injury/vessel stenosis. At exit, 1 child (alternative arm) had a newsilent infarct, and another had worse stenosis. SWiTCH neuroimaging data document severe parenchymal and vascular abnormalities in children with SCA and stroke and support concerns about chronic transfusions lacking effectiveness for preventing progressive cerebrovascular injury. The novel SWiTCH vasculopathy grading scale warrants validation testing and consideration for use in future clinical trials.

Original languageEnglish (US)
Pages (from-to)891-898
Number of pages8
Issue number6
StatePublished - Aug 7 2014
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology


Dive into the research topics of 'Magnetic resonance imaging/angiography and transcranial Doppler velocities in sickle cell anemia: Results from the SWiTCH trial'. Together they form a unique fingerprint.

Cite this