Patterns of diffusion-weighted magnetic resonance imaging associated with etiology improve the accuracy of prognosis after transient ischaemic attack.

Objective: diffusion-weighted magnetic resonance imaging (DWI) is a sensitive diagnostic tool for detecting acute ischaemic lesions in patients with transient ischaemic attacks (TIAs). The additional predictive value of DWI lesion patterns is not well known.

Methods: two hundred and fifty-four consecutive patients with TIA underwent DWI within 7 days of symptom onset. The presence and pattern of acute ischaemic lesions were related to clinical features, etiology, and stroke recurrence at seven- and 90-day follow-up.

Results: diffusion-weighted images abnormalities were identified in 117 (46.1%) patients. The distribution of DWI lesions was cortical, 31; subcortical, 32; scattered lesions in one arterial territory (SPOT) 42; and in multiple areas, 12. SPOT were significantly associated with motor weakness, large-artery atherosclerosis (LAA), and the cardioembolic subtype of TIA. Single cortical lesions were also associated with cardioembolism, whereas subcortical acute lesions were associated with recurrent episodes, dysarthria, and motor weakness. During follow-up, seven patients had a stroke within 7 days (2.8%, 95% CI 2.9-6.4%), and 12 had a stroke within 3 months (4.7%%, 95% CI 2.9-6.4%). In the Cox logistic regression model, the combination of LAA and positive DWI remained as independent predictors of stroke recurrence at 90-day follow-up (HR 5.78, 95 CI 1.74-19.21, P = 0.004).

Conclusion: according to our results, MRI, including DWI, should be considered a preferred diagnostic test when investigating patients with potential TIAs. The combination of neuroimaging and vascular information could improve prognostic accuracy in patients with TIA.