Diffusion weighted magnetic resonance imaging of compromised tissue in stroke.

Diffusion weighted imaging (DWI) and T2 weighted magnetic resonance imaging were performed on at least two occasions in 28 children presenting with stroke. In previous reports of DWI in human stroke, eventual infarction was observed (with only one exception) in all regions in which early DWI hyperintensity occurred. In the present report, two children had regions of DWI hyperintensity which did not progress to infarction. One patient who presented with right hemiplegia showed extensive high signal on DWI, with T2 evidence of tissue swelling but without hyperintensity. DWI changes persisted over weeks, with no imaging indication of infarction. This child recovered completely. A second child who had a major vessel infarct with concomitant regions of hyperintensity on T2 weighted imaging and DWI, also had DWI hyperintensity in an adjacent territory which did not develop any subsequent evidence of infarction. Thus in clinical practice DWI can demonstrate tissue which is compromised but not irreversibly so.