Background: It is recognized that complicated plaque largely accounts for the morbidity and mortality from atherosclerosis. Ideally, investigation of symptomatic and asymptomatic patients would identify atheromatous plaques independently of stenosis. We have previously shown that a magnetic resonance direct thrombus imaging (MRDTI) technique demonstrates complicated atheroma as high signal within the carotid arterial wall. We used this technique to examine the prevalence of complicated carotid plaque in vivo in the ipsilateral arteries of recently symptomatic patients with suspected carotid artery stenosis and to compare this with their contralateral arteries and with those of healthy age- and sex-matched controls.
Methods and results: The carotid arteries of 120 patients with suspected severe carotid artery stenosis and previous acute cerebral ischemia were imaged using MRDTI, as were 28 control arteries. High signal was not seen in any control artery. However, there was a 60% prevalence of high signal, suggestive of complicated plaque in the patients' ipsilateral arteries. The prevalence of high signal was significantly greater in the patients' ipsilateral vessels compared with the contralateral, asymptomatic side (60% versus 36%, chi2 P<0.001), particularly for vessels of only moderate stenosis.
Conclusions: MRDTI high signal suggestive of complicated plaque is prevalent in the ipsilateral carotid arteries of patients with carotid stenosis and recent cerebral ischemic events. MRDTI has a potential role in identifying "at risk" plaque, studying atherogenesis and the effects of plaque-modifying strategies.