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Existence of the diffusion-perfusion mismatch within 24 hours after onset of acute stroke: dependence on proximal

William A Copen1, Leila Rezai Gharai, Elizabeth R Barak

  • 1Department of Radiology, Massachusetts General Hospital, GRB-273A, 55 Fruit St, Boston, MA 02114, USA. wcopen@partners.org

Radiology
|January 24, 2009
PubMed
Abstract

Insights

Mismatch between diffusion-weighted and perfusion-weighted MRI scans in acute stroke patients is common, especially with proximal arterial occlusion. This mismatch often persists beyond 9 hours post-stroke onset.

Area of Science:

  • Neurology
  • Radiology
  • Medical Imaging

Background:

  • Acute stroke diagnosis relies on timely imaging to identify ischemic areas.
  • Diffusion-weighted (DW) and perfusion-weighted (PW) magnetic resonance (MR) imaging are crucial for assessing stroke extent and potential salvageable brain tissue.
  • Understanding the relationship between imaging findings and arterial occlusion is vital for treatment decisions.

Purpose of the Study:

  • To evaluate the presence of a mismatch between DW and PW MR imaging lesions within 24 hours of acute stroke onset.
  • To determine if this mismatch is dependent on the presence of proximal arterial occlusion (PAO).
  • To assess the impact of PAO on the persistence of imaging mismatch over time.

Main Methods:

  • Retrospective analysis of 109 patients with acute stroke who underwent DW and PW MR imaging within 24 hours.
  • Calculation of relative mismatch volume using DW lesion volume and mean transit time maps.
  • Categorization of patients into PAO (n=68) and non-PAO (NPAO, n=41) groups based on CT or MR angiography.
  • Evaluation of thrombolysis eligibility using established criteria (DIAS/DEDAS) and a 160% mismatch threshold.

Main Results:

  • 71% of patients met DIAS-DEDAS criteria and 56% met the 160% mismatch criterion for hypothetical thrombolysis.
  • NPAO patients showed decreasing eligibility with increasing time from stroke onset, particularly after 9 hours.
  • PAO patients demonstrated a trend towards increasing eligibility with time and maintained eligibility after 9 hours, unlike NPAO patients.

Conclusions:

  • A mismatch between DW and PW MR imaging findings is frequently observed in acute stroke patients.
  • The persistence of this mismatch beyond 9 hours is common, particularly in patients with proximal arterial occlusion.
  • These findings highlight the importance of considering arterial occlusion status when interpreting imaging mismatch in acute stroke.

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