[MR investigations in stroke]

In the article digital imaging methods are presented with special emphasis on the use on diagnostics of cerebral circulation studies. Recently, fundamental changes have happened in this field, concerning especially the MR investigations. These changes have influenced the therapeutic strategies of ischaemic stroke. Authors give the theoretical background on the diffusion and perfusion MR imaging, emphasising the importance of their "mismatch" and its impact in the estimation of the outcome of ischaemic events. More recently, new, controversial facts arose, regarding the reasons of the introduction of the theory of so called "negative" and "positive" mismatches. As a consequence, a level of uncertainty took place in the judgement of prognostics. The leading institutions are searching the way to solve the problem which seems to be the quantitative evaluation of the diffusion, perfusion and mismatch data. The advent of the multislice spiral CT with very fast imaging and the importance of CT investigations increased. With this new kind of equipment, even perfusion studies can be performed using iodinated contrast medium.