This Article Full Text Full Text (PDF) All Versions of this Article: 38/4/1336    most recent 01.STR.0000259636.26950.3bv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bardutzky, J. Articles by Fisher, M. Search for Related Content PubMed PubMed Citation Articles by Bardutzky, J. Articles by Fisher, M. Pubmed/NCBI databases Medline Plus Health Information Transient Ischemic Attack Related Collections Acute Cerebral Infarction Brain Circulation and Metabolism Computerized tomography and Magnetic Resonance Imaging

(Stroke. 2007;38:1336.)
© 2007 American Heart Association, Inc.

Original Contributions

Characterizing Tissue Fate After Transient Cerebral Ischemia of Varying Duration Using Quantitative Diffusion and Perfusion Imaging

Juergen Bardutzky, MD; Qiang Shen, PhD; Nils Henninger, MD; Stefan Schwab, MD; Timothy Q. Duong, PhD Marc Fisher, MD

From the Department of Neurology (J.B., N.H., M.F.), University of Massachusetts Medical School, Worcester, Mass; the Department of Neurology (Q.S., T.Q.D.), Yerkes National Primate Research Center, Emory University, Atlanta, Ga; the Department of Neurology (J.B.), University of Heidelberg, Germany; and the Department of Neurology (S.S.), University of Erlangen, Germany.

Correspondence to Juergen Bardutzky, MD, Department of Neurology, University of Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany. E-mail juergen.bardutzky{at}neuro.imed.uni-erlangen.de

Background and Purpose— The purpose of this study was to investigate the effects of reperfusion on ischemic lesion evolution and pixel-by-pixel apparent diffusion coefficient–cerebral blood flow (ADC-CBF) dynamics of core and mismatch tissues after 35, 60, and 95 minutes of transient focal ischemia in rats (n=28).

Methods— Serial diffusion-, perfusion-, and T2-weighted imaging were performed up to 24 hours. The evolution of the magnetic resonance image-derived lesion volume was investigated and ADC-CBF scatterplots were performed to prospectively characterize the ADC and CBF dynamics of core and mismatch tissues with different fates. For comparison, similar analysis was performed on a historical 60-minute transient ischemia and permanent ischemia group.

Results— ADC-derived lesions markedly decreased on reperfusion at 35 minutes to an average of 15±5% of prereperfusion lesion size (P<0.00001). At 24 hours, lesion volume as determined by T2 imaging increased again to 51±10% of prereperfusion lesion size. In the 95-minute group, ADC lesions only briefly decreased on reperfusion and then secondarily enlarged at 180 minutes, almost reaching prereperfusion lesion volume. Pixel-based analysis demonstrated that >85% of mismatch pixels were salvaged by reperfusion independent of ischemia duration. Recanalization at 35, 60, and 95 minutes resulted in recovery of 46%, 28%, and 9% of core pixels, respectively. Core and mismatch pixels that were ultimately salvaged had persistently higher (P<0.001) CBF values during ischemia in all reperfusion groups, associated with higher (P<0.05) ADC values.

Conclusion— This study demonstrated substantial salvage of mismatch tissue after reperfusion independent of ischemia duration and substantial permanent recovery of initial core pixels with early reperfusion. Severity of CBF reduction during ischemia seems to be the main factor determining tissue fate.

Key Words: brain ischemia • MRI • reperfusion