Introduction Magnetic resonance imaging (MRI) of the carotid artery can provide detailed information on atherosclerotic plaque structure, but to date has not been applied to patients with acute (<1 week) events such as transient ischaemic attack (TIA) or minor stroke.
Hypothesis 3T MRI of the carotid artery can identify atherosclerotic plaque rupture in patients presenting with TIA or minor stroke.
Methods 22 patients presenting with TIA or minor stroke underwent T1, T2 and proton density-weighted turbo spin echo imaging to 10 mm either side of the carotid bifurcation (in-plane resolution 0.47 mm × 0.47 mm) and time-of-flight magnetic resonance angiography. Plaques were graded according to the MRI modified American Heart Association (AHA) system; statistical analyses were performed using χ2 and Mann–Whitney tests.
Results 15/22 patients were men (age (mean ± SD 69.8 ± 20.3); the median time from symptom onset to imaging was 45 h. Plaque characterisation was technically feasible in 313/381 (82%) images. Type VI (complicated) plaque was seen in 12 cases and was more prevalent in the culprit carotid artery than the contralateral artery (12 vs 0; p = 0.001). Of these 12 plaques, seven showed evidence of surface disruption (fig, panel A), two had associated intraluminal thrombus (panel B) and three showed bright signal suggestive of intraplaque haemorrhage (panel C). Mean plaque area was also greater in the culprit artery (0.59 cm2 vs 0.44 cm2; p = 0.05).
Conclusion We present the first study demonstrating the ability of 3T MRI to show the early features of plaque rupture in an acutely symptomatic population. Future work will investigate the relationship between the changes seen and clinical prognosis.