Reliability of assessing percentage of diffusion-perfusion mismatch

Shelagh B. Coutts, Jessica E. Simon, Anna I. Tomanek, Philip A. Barber, Jean Chan, Mark E. Hudon, J. Ross Mitchell, Richard Frayne, Michael Eliasziw, Alastair M. Buchan, Andrew M. Demchuk

Research output: Contribution to journalArticlepeer-review

93 Scopus citations


Background and Purpose - Emergent neurovascular imaging holds promise in identifying new and optimum target populations for thrombolysis in stroke. Recent research has focused on patients with diffusion-weighted MRI (DWI)-perfusion-weighted MRI (PWI) mismatch as a marker of tissue at risk of infarction and a means to select the most suitable candidates for thrombolysis. The present study sought to estimate the reliability of assessing the percentage of DWI-PWI mismatch. Methods - Thirteen patients with acute strokes had DWI and PWI within 7 hours of symptom onset. Six raters independently created relative mean transit time (rMTT) maps and then compared them with DWI images to assess the percentage of mismatch (PWI>DWI) in 10% increments. The MR scans were reassessed by 4 raters, tracing around the lesions to calculate the volume percentage of mismatch. Results - Visual assessment had an interrater reliability of 0.68 (95% CI, 0.52 to 1.0; SEM=21.6%) and an intrarater reliability of 0.80 (95% CI, 0.47 to 1.0; SEM= 16.9%). Hand-drawn assessment had an interrater reliability of 0.66 (95% CI, 0.45 to 1.0; SEM=26.2%) and an intrarater reliability of 0.94 (95% CI, 0.81 to 1.0; SEM=10.9%). Conclusions - Results from the present study suggest that quantifying mismatch by the human eye is reproducible but not reliable among observers. This raises doubts about using mismatch for clinical decision making and clinical trial enrollment.

Original languageEnglish (US)
Pages (from-to)1681-1683
Number of pages3
Issue number7
StatePublished - Jul 1 2003


  • Magnetic resonance imaging, diffusion-weighted
  • Magnetic resonance imaging, perfusion-weighted
  • Penumbra
  • Stroke, acute

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialized Nursing


Dive into the research topics of 'Reliability of assessing percentage of diffusion-perfusion mismatch'. Together they form a unique fingerprint.

Cite this