Reperfusion beyond 6 hours reduces infarct probability in moderately ischemic brain tissue

Hongyu An, Andria L. Ford, Cihat Eldeniz, Yasheng Chen, Katie D. Vo, Hongtu Zhu, William J. Powers, Weili Lin, Jin Moo Lee

Research output: Contribution to journalArticle

4 Scopus citations


Background and Purpose - We aimed to examine perfusion changes between 3 and 6 and 6 and 24 hours after stroke onset and their impact on tissue outcome. Methods - Acute ischemic stroke patients underwent perfusion magnetic resonance imaging at 3, 6, and 24 hours after stroke onset and follow-up fluid-attenuated inversion recovery at 1 month to assess tissue fate. Mean transit time prolongation maps (MTTp=MTT-[median MTT of contralateral hemisphere]) were obtained at 3 (MTTp3 h), 6 (MTTp6 h), and 24 hours (MTTp24 h). Perfusion changes between 3 and 6 hours (ΔMTTp3-6) and 6 and 24 hours (ΔMTTp6-24) were calculated. A 2-step analysis was performed to evaluate the impact of ΔMTTp3-6 and ΔMTTp6-24 on tissue fate. First, a voxel-based multivariable logistic regression was performed for each individual patient with MTTp3 h, ΔMTTp3-6, and ΔMTT6-24 as independent variables and tissue fate as outcome. Second, Wilcoxon signed-rank tests on logistic regression coefficients were performed across patients to evaluate whether ΔMTTp3-6 and ΔMTT6-24 had significant impact on tissue fate for varying severities of baseline perfusion. Results - Perfusion change was common during both time periods: 85% and 81% of patients had perfusion improvement during 3- to 6- and 6- and 24-hour time intervals, respectively. ΔMTT3-6 significantly influenced 1-month infarct probability across a wide range of baseline perfusion (MTTp 0-15 s). ΔMTT6-24 also impacted 1-month infarct probability, but its influence was restricted to tissue with milder baseline ischemia (MTTp 0-10 s). Conclusions - Brain tissue with mild to moderate ischemia can be salvaged by reperfusion even after 6 hours. Such tissue could be targeted for intervention beyond current treatment windows.

Original languageEnglish
Pages (from-to)99-105
Number of pages7
Issue number1
StatePublished - Jan 1 2016


  • MR perfusion imaging
  • brain
  • ischemia
  • reperfusion
  • stroke
  • tissue outcome

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