Reduced oxygen extraction efficiency in sickle cell anemia patients with evidence of cerebral capillary shunting

J Cereb Blood Flow Metab. 2021 Mar;41(3):546-560. doi: 10.1177/0271678X20913123. Epub 2020 Apr 11.

Abstract

Arterial spin labeling (ASL) magnetic resonance imaging (MRI) utilizes arterial blood water as an endogenous contrast agent to provide a quantitative measure of cerebral blood flow (CBF). Recently, hyperintense signal within dural venous sinuses in ASL images of sickle cell anemia (SCA) patients has been shown to be consistent with elevated flow velocities and may indicate capillary shunting and reduced oxygen extraction. Here, we performed oxygen extraction fraction (OEF) and CBF measurements in adults (cumulative n = 114) with (n = 69) and without (n = 45) SCA to test the hypothesis that hyperintense venous ASL signal is associated with reduced OEF. Higher categorical scores of shunting on ASL MRI were associated with lower OEF in participants with silent cerebral infarcts or white matter hyperintensities (p = 0.003), but not in those without lesions (p = 0.551). These findings indicate that venous hyperintense signal in ASL images in SCA patients may represent a marker of capillary-level disturbances in oxygen exchange efficiency and small vessel pathology.

Keywords: Capillary shunting; oxygen exchange efficiency; sickle cell anemia; silent cerebral infarcts; white matter hyperintensities.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anemia, Sickle Cell / physiopathology*
  • Brain / diagnostic imaging
  • Brain / physiology
  • Capillaries / physiopathology*
  • Cerebral Infarction / etiology
  • Cerebrovascular Circulation / physiology*
  • Contrast Media / chemistry
  • Coronary Angiography
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Oxygen / metabolism*
  • Spin Labels
  • White Matter / physiopathology
  • Young Adult

Substances

  • Contrast Media
  • Spin Labels
  • Oxygen