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Fragmentation of the classical magnetic resonance mismatch "penumbral" pattern with time

Henry Ma1, Jorge A Zavala, Hock Teoh

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

Stroke
|October 24, 2009
PubMed
Abstract

Insights

The classical mismatch pattern in stroke imaging may fragment over time. This pattern is more common earlier after stroke onset, with vessel occlusion and larger mismatch volumes.

Area of Science:

  • Neurology
  • Radiology
  • Medical Imaging

Background:

  • The classical mismatch pattern on MRI in middle cerebral artery stroke involves a diffusion-weighted image core surrounded by mismatch tissue.
  • This pattern's fragmentation over time is a potential concern due to variable tissue salvage rates.

Purpose of the Study:

  • To investigate the temporal fragmentation of the classical mismatch pattern in ischemic stroke.
  • To determine factors influencing the persistence or fragmentation of this pattern, including vessel patency, mismatch volume, and infarct core location.

Main Methods:

  • Patients with ischemic stroke underwent MRI within 48 hours of symptom onset.
  • Mismatch patterns were classified as classical or nonclassical (fragmented) based on diffusion-weighted and perfusion-weighted imaging.
  • The study assessed the proportion of patterns in relation to time, vessel patency, mismatch volume, and infarct core location.

Main Results:

  • Of 67 patients, 49.3% showed a classical pattern and 50.7% a nonclassical pattern.
  • The classical pattern was associated with earlier MRI times (3.4 vs 10.4 hours) and larger mismatch volumes (62.0 vs 3.5 mL) compared to the nonclassical pattern.
  • Earlier time, vessel occlusion, superficial core location, and larger mismatch volume predicted the classical pattern.

Conclusions:

  • The classical mismatch pattern can fragment over time.
  • Within 48 hours post-stroke, the classical pattern is observed earlier, with higher rates of vessel occlusion and larger mismatch volumes.

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