Background: To evaluate whether topographical characteristics of insular involvement in ischemic stroke are associated with cardioembolism.
Methods and findings: A consecutive series of patients hospitalized for ischemic stroke within 7 days of symptom onset were identified. Based on diffusion-weighted imaging, we included those who had ischemic lesions in the middle cerebral artery (MCA) territory. Each patient was assigned to one of two groups based on the presence or absence of insular involvement. The primary outcome was the frequency of cardioembolism, which was compared based on insular involvement. Of 1,311 patients with ischemic stroke in the MCA territory, 112 had insular involvement (8.5%). The frequency of cardioembolism in patients with insular involvement (52.7%) was significantly higher than that in patients without insular involvement (30.4%, P < 0.001). Although insular involvement was associated with a severe baseline National Institutes of Health Stroke Scale score (13 vs. 4), it did not independently affect the 3-month functional outcome.
Conclusions: In cases of stroke in the MCA territory, involvement of the insular cortex may be associated with a risk of cardioembolism.