Hypointense Vessels Detected by Susceptibility-Weighted Imaging Identifies Tissue at Risk of Infarction in Anterior Circulation Stroke

J Neuroimaging. 2017 Jul;27(4):414-420. doi: 10.1111/jon.12417. Epub 2016 Dec 21.

Abstract

Background and purpose: The diagnostic value of susceptibility-weighted magnetic resonance imaging of acute stroke patients has shown potential as a surrogate marker of impaired hemodynamics. We investigate the value of asymmetrical hypointense cerebral vessels (HV) for the identification of vessel status and tissue at risk of infarction (TaR).

Methods: Symmetry of HV was visually rated on SWI data from a well-defined population of acute anterior circulation stroke with onset <24 hours. MRI perfusion data was analyzed and volumes of tissue at risk segmented using a delay threshold of Tmax> 6 seconds. Status of the extra- and intracranial arteries was assessed by ultrasound and MR angiography.

Results: 35 patients were included (12 women; median age 69 years, IQR 61-77; median NIHSS at admission 10, IQR 6-20). Asymmetrically distributed HV were detected at the stroke hemisphere in 25 patients (71%). Of those, 12 patients displayed occlusion of the middle cerebral artery, whereas occlusion of the extracranial ICA was detected in 6 patients. TaR was larger, yet not significantly different in patients with asymmetrically HV (mean volume 38.9 ml, SD 52.9 ml) compared to patients showing symmetrical HV (4.2 ml; SD 10.7 ml, p-value 0.081). Significant differences where, however, found after excluding patients with extracranial ICA occlusions (42.9 ml; SD 50.4 ml vs. 4.2 ml, SD 10.8 ml, p-value 0.025).

Conclusion: Visual analysis of HV in SWI identifies tissue at risk in patients with anterior circulation stroke. Potentially pre-existing extracranial ICA occlusions leading to prominent HV have to be considered as a confounding factor.

Keywords: Ischemic stroke; hypointense vessels; magnetic resonance imaging; susceptibility-weighted imaging; tissue at risk of infarction.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Brain / diagnostic imaging*
  • Brain / pathology
  • Brain Ischemia / diagnostic imaging*
  • Brain Ischemia / pathology
  • Cerebrovascular Circulation / physiology
  • Female
  • Humans
  • Magnetic Resonance Angiography / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Stroke / diagnostic imaging*
  • Stroke / pathology
  • Ultrasonography