1. ^*Department of Clinical Radiology, Kuopio University Hospital, Finland
2. ^‡Department of Neurology, Kuopio University Hospital, Finland
3. ^¶Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Finland
4. ^#Niuvanniemi Hospital, Kuopio, Finland
5. ^§Department of Radiology, Helsinki University Central Hospital
6. Department of Physics, University of Helsinki, Helsinki, Finland
7. ^†Department of Neuroradiology, Århus University Hospital, Århus, Denmark

Correspondence: Hannu J Aronen, Department of Clinical Radiology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland

Received 11 November 1999; Revised 10 March 2000; Accepted 15 March 2000.

Abstract

Nineteen patients with acute ischemic stroke (<24 hours) underwent diffusion-weighted and perfusion-weighted (PWI) magnetic resonance imaging at the acute stage and 1 week later. Eleven patients also underwent technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (SPECT) at the acute stage. Relative (ischemic vs. contralateral control) cerebral blood flow (relCBF), relative cerebral blood volume, and relative mean transit time were measured in the ischemic core, in the area of infarct growth, and in the eventually viable ischemic tissue on PWI maps. The relCBF was also measured from SPECT. There was a curvilinear relationship between the relCBF measured from PWI and SPECT (r = 0.854; P < 0.001). The tissue proceeding to infarction during the follow-up had significantly lower initial CBF and cerebral blood volume values on PWI maps (P < 0.001) than the eventually viable ischemic tissue had. The best value for discriminating the area of infarct growth from the eventually viable ischemic tissue was 48% for PWI relCBF and 87% for PWI relative cerebral blood volume. Combined diffusion and perfusion-weighted imaging enables one to detect hemodynamically different subregions inside the initial perfusion abnormality. Tissue survival may be different in these subregions and may be predicted.