Large cohort studies have defined an increasing range of therapeutic interventions that can be applied to reduce stroke risk. However, application of these in a specialist practice is complicated by the problem of interindividual variation. A major practical issue is to differentiate those patients who will do well on standard treatment from those for whom a specifically targeted, more aggressive approach is needed. Ideally, it would be possible to profile patients at presentation to identify those at highest risk. If such a strategy could be made reliable, it would help simultaneously to balance a commitment to provide the best care available for each patient and to reassure government and other funders that potentially expensive therapeutic interventions are being employed in the most cost-effective fashion.

MRI provides an attractive tool for stratifying risk in a stroke population. It offers a good definition of brain injury and promises to …