Relevance of neuroimaging in the evaluation of cerebral ischemia.

The rapid development of neuroimaging techniques has provided us with a wide range of tools for the assessment of patients who may have experienced cerebrovascular events. Each of these technologies provides specific and potentially informative insights. For clinical practice, however, we always have to tailor our diagnostic approach according to a maximum benefit/minimal burden and cost ratio. We, therefore, propose a diagnostic algorithm which is tailored according to stroke phase and availability of distinct therapeutic strategies. In the acute phase of ischemic stroke, patients can be segregated into those who are potentially amenable to systemic thrombolysis within 3 h and into possible candidates for (i.v. or i.a.) thrombolysis outside approved criteria both within and beyond this time window. For patients in the postacute phase of acute ischemic stroke, neuroimaging should contribute a maximum of information to the clarification of stroke etiology to allow for specific secondary prevention. Patients with transient ischemic attacks appear to represent yet another distinct group of patients who can benefit greatly from a rapid and comprehensive neuroimaging evaluation, as this allows identification of individuals at a specifically high risk for a subsequent stroke. Using these categories, the relevance of respective neuroimaging tools can be substantiated by a large body of evidence.