Related Experiment Video

Updated: Jun 4, 2026

Brain Infarct Segmentation and Registration on MRI or CT for Lesion-symptom Mapping
10:25

Brain Infarct Segmentation and Registration on MRI or CT for Lesion-symptom Mapping

Published on: September 25, 2019

The hidden mismatch: an explanation for infarct growth without perfusion-weighted imaging/diffusion-weighted imaging

Henry K Ma1, Jorge A Zavala, Leonid Churilov

  • 1National Stroke Research Institute, Austin Health, University of Melbourne, 300 Waterdale Road, Heidelberg West, Victoria 3081, Australia.

Stroke
|February 5, 2011
PubMed
Abstract

Insights

Hidden mismatch in ischemic stroke, detected by coregistration, explains infarct growth beyond initial imaging. This finding improves understanding of tissue at risk and salvageable tissue in stroke patients.

Area of Science:

  • Neurology
  • Radiology
  • Medical Imaging

Background:

  • Ischemic stroke involves tissue at risk, identified by MR perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch.
  • Infarct growth typically occurs within the mismatch area, but discrepancies have been reported.
  • Undetected "hidden mismatch" may explain observed infarct growth exceeding apparent PWI/DWI mismatch.

Purpose of the Study:

  • To investigate the hypothesis that "hidden mismatch" is detectable using coregistration techniques.
  • To explain instances where infarct growth appears to exceed the initially identified PWI/DWI mismatch.
  • To quantify salvageable tissue using coregistration methods in ischemic stroke.

Main Methods:

  • Performed MR PWI/DWI within 48 hours of stroke onset and T2-weighted imaging at 3 months.
  • Defined volumetric-subtraction mismatch as PWI minus DWI volume; infarct growth as T2 minus DWI volume.
  • Quantified coregistration mismatch as PWI not overlapped by DWI and calculated mismatch salvage.

Main Results:

  • Thirty-four patients were analyzed, with MR scans at a median of 4.9 hours post-stroke.
  • Volumetric-subtraction showed infarct growth exceeding mismatch in 14.7% of patients; 32.0% had no initial mismatch, with 27.3% of those showing infarct growth.
  • Coregistration identified mismatch volume greater than infarct growth in all patients, with a median salvage proportion of 77.7%.

Conclusions:

  • The "hidden mismatch" concept, detectable by coregistration, resolves the paradox of infarct growth exceeding apparent PWI/DWI mismatch.
  • Coregistration techniques enhance the identification of tissue at risk and improve the assessment of salvageable brain tissue in ischemic stroke.
  • This refined understanding of mismatch is crucial for accurate prognostication and treatment decisions in stroke management.

More Related Videos

A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia09:59

A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia

Published on: September 16, 2017

Related Concept Videos

Ischemic Stroke ll: Pathophysiology01:15

Ischemic Stroke ll: Pathophysiology

An ischemic stroke occurs when a cerebral blood vessel becomes obstructed, most often by a thrombus or embolus, interrupting the delivery of oxygen and glucose to brain tissue. Because neurons rely on continuous aerobic metabolism, energy failure begins within minutes of reduced perfusion. The region receiving the least blood flow becomes the infarct core, an area of irreversible cellular death. Surrounding this core lies the penumbra, a zone of hypoperfused but still viable tissue that is...
Ischemic Stroke l: Introduction01:15

Ischemic Stroke l: Introduction

Ischemic stroke is an acute cerebrovascular condition in which blood flow to a brain region is suddenly interrupted, leading to tissue infarction. Neurons depend on continuous oxygen and glucose supply, so even brief reductions in perfusion cause energy failure, ionic imbalance, and irreversible injury. Ischemic strokes are classified into thrombotic and embolic types based on their underlying mechanisms.Thrombotic MechanismsThrombotic stroke develops when a clot forms within a cerebral artery.
Transient Ischemic Attack l: Introduction01:26

Transient Ischemic Attack l: Introduction

A transient ischemic attack (TIA) is a brief episode of neurological dysfunction caused by a temporary, focal reduction in cerebral blood flow. Although symptoms resemble those of an ischemic stroke, the interruption in perfusion is short-lived and does not cause permanent infarction. TIAs are clinically important because they often serve as early warning events for future stroke.Mechanisms of Transient Cerebral IschemiaTransient cerebral ischemia may arise through several mechanisms. One...