MRI-guided selection of patients for treatment of acute ischemic stroke

PURPOSE OF REVIEW: To summarize what is known about the use of MRI in acute stroke treatment (predominantly thrombolysis), to examine the assumptions and theories behind the interpretation of magnetic resonance images of acute ischemic stroke and how they are used to select patients for therapies, and to suggest directions for future research. RECENT FINDINGS: Recent studies have been contradictory about the usefulness of MRI in selecting patients for treatment. New MRI models for selecting patients have emerged that focus not only on the ischemic penumbra but also on the infarct core. Fixed time-window selection parameters are being replaced by timing-based individualized MRI stroke features. New ways to interpret traditional MRI stroke sequences are emerging. SUMMARY: Although the efficacy of acute stroke treatment is time dependent, the use of fixed time windows cannot account for individual differences in infarct evolution, which could potentially be detected with MRI. Although MRI shows promise for identifying patients who should be treated, as well as excluding patients who should not be treated, definitive evidence is still lacking. Future research should focus on validating the use of MRI to select patients for intravenous therapies in extended time windows.