Imaging the physiological evolution of the ischemic penumbra in acute ischemic stroke

Research output: Contribution to journalReview articlepeer-review

Abstract

We review the hemodynamic, metabolic and cellular parameters affected during early ischemia and their changes as a function of approximate cerebral blood flow (CBF) thresholds. These parameters underlie the current practical definition of an ischemic penumbra, namely metabolically affected but still viable brain tissue. Such tissue is at risk of infarction under continuing conditions of reduced CBF, but can be rescued through timely intervention. This definition will be useful in clinical diagnosis only if imaging techniques exist that can rapidly, and with sufficient accuracy, visualize the existence of a mismatch between such a metabolically affected area and regions that have suffered cell depolarization. Unfortunately, clinical data show that defining the outer boundary of the penumbra based solely on perfusion-related thresholds may not be sufficiently accurate. Also, thresholds for CBF and cerebral blood volume (CBV) differ for white and gray matter and evolve with time for both inner and outer penumbral boundaries. As such, practical penumbral imaging would involve parameters in which the physiology is immediately displayed in a manner independent of baseline CBF or CBF threshold, namely pH, oxygen extraction fraction (OEF), diffusion constant and mean transit time (MTT). Suitable imaging technologies will need to meet this requirement in a 10–20 min exam.

Original languageEnglish (US)
Pages (from-to)1500-1516
Number of pages17
JournalJournal of Cerebral Blood Flow and Metabolism
Volume38
Issue number9
DOIs
StatePublished - Sep 1 2018

Keywords

  • Acidosis
  • MRI
  • ischemic penumbra
  • metabolism
  • pH
  • perfusion
  • physiologic evolution

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'Imaging the physiological evolution of the ischemic penumbra in acute ischemic stroke'. Together they form a unique fingerprint.

Cite this