Purpose: The aim of this study was to show the temporal and spatial evolution of ischaemia over time using diffusion-weighted magnetic resonance imaging, and to correlate the extent of ischaemia with the postmortem infarct size after 24 hours.
Material and methods: In 8 rats focal cerebral ischaemia was induced by intravascular occlusion of the middle cerebral artery. The evolution of the ischaemic lesion was examined over 180 min with an experimental MR scanner.
Results: Diffusion-weighted magnetic resonance imaging displayed a hyperintense area in the lateral part of the putamen as early as 5 min after the onset of ischaemia. The mean volume of ischaemia on diffusion mapping after 5 min was 62.5 +/- 12.9 microliters and increased to 224.4 +/- 48.5 microliters after 180 min. This correlated well with the corrected infarct volume at postmortem examination (194.0 +/- 23.1 microliters, r = 0.72, p < 0.05) using the TTC staining.
Conclusion: Diffusion-weighted magnetic resonance imaging is a reliable tool in the early diagnosis of cerebral ischaemia. Due to the non-invasiveness this method can be used for therapy monitoring and might help to develop new therapeutic strategies.