The significance of TOF MRA as non-invasive imaging of intraplaque hemorrhage in patients with acute symptomatic carotid disease

Abstract

Carotid intraplaque hemorrhage (IPH) is well known for a risk factor of ischemic stroke. In patient with hyperacute stage of symptomatic carotid stenosis, Time of flight (TOF) MR angiography (MRA) can screen carotid disease rapidly in addition to taking routine MRI. Using TOF MRA, we evaluated carotid IPH, and we also examined associated stroke patterns and clinical outcomes. We reviewed 59 patients who had symptomatic carotid artery disease detected by TOF MRA. They visited SNUBH within 12 hours of stroke symptom onset. Patients were assigned to those who had IPH or had not on TOF MRA. The degree of carotid stenosis was evaluated according to the NASCET criteria. Diffusion weighted imaging (DWI) MRI lesion patterns were classified as (1) large territorial infarction, (2) disseminated small infarction, and (3) border-zone infarction. Also, we observed early neurological deterioration (END) and clinical outcomes (recurrence of stroke, myocardial infarction, or death from any cause) at 3 months and 1 year. IPH was detected in 28.8% of total enrolled patients (17/59). The patients with mild to moderate symptomatic carotid stenosis are more in the IPH positive group (70.6%) than the IPH negative group (42.8%). The patients with the IPH positive group more frequently demonstrated disseminated small infarction pattern (76.5% in the IPH(+) group, 47.6% in the IPH(-) group), and less frequently showed border-zone infarction pattern (0% in the IPH(+) group, 16.7% in the IPH(-) group) than the patients with the IPH negative group. END and clinical outcomes at 3 months were not different between the two groups. In conclusion, the patients with IPH positive group are more likely to cause symptomatic stroke than IPH negative group even if they have smaller degree of carotid stenosis. TOF MRA can detect this stenosis in the hyperacute stage, so it is possible to determine the mechanism of stroke and establish treatment plan early with this method. And our results suggest that disseminated small infarction pattern is more frequent in the IPH positive group than the IPH negative group, and border-zone infarct pattern is less specific for the IPH positive group. Clinical outcomes were similar in both two groups.