Prevalence of Complicated Carotid Atheroma as Detected by Magnetic Resonance Direct Thrombus Imaging in Patients With Suspected Carotid Artery Stenosis and Previous Acute Cerebral Ischemia

Abstract

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%, 2 PϽ0.001), 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. (Circulation. 2003;107:3053-3058.)

Geometric and Compositional Appearance of Atheroma in an Angiographically Normal Carotid Artery in Patients with Atherosclerosis

“…[21][22][23][24][25] In the carotid artery, these features have been shown prospectively to be associated with a higher risk of plaque progression 26 and future cerebrovascular events. 27 As such, vessel wall imaging may provide critical information for discerning lesion stability, particularly in all asymptomatic and symptomatic lesions with Ͻ70% stenosis when treatment strategies remain ambiguous.…”

Appropriate Selection of CAS or CEA and Proper Use of Protection Device in the Event of CAS According to Carotid Plaque Characteristics

“…As a result, the Carotid artery plaques cause not only stenosis or occlusion of the vascular lumen but also artery to artery embolism due to their vulnerability. [13][14][15] Recently, after various EPDs for CAS have begun to be covered by insurance, the number of patients undergoing CAS has increased, but the risks of CAS including distal embolism and intra-procedural filter clogging have also begun to be recognized. Under these circumstances, qualitative assessment of plaques and accurate evaluation of their vulnerability have become possible by the black blood MRI technique for carotid artery plaque, by which the signals in the vascular lumen are suppressed, and the technique is applied to the pre-procedural assessment of unstable plaques, which are likely to cause complications in CAS.…”

“…Under these circumstances, qualitative assessment of plaques and accurate evaluation of their vulnerability have become possible by the black blood MRI technique for carotid artery plaque, by which the signals in the vascular lumen are suppressed, and the technique is applied to the pre-procedural assessment of unstable plaques, which are likely to cause complications in CAS. [16][17][18][19] High-risk unstable plaques are soft, have a thin capsule, and contain large atheroma or intraplaque hematoma, [14][15][16][17][18][19][20] and, as shown in Table 2, components of hematoma and atheroma exhibit high intensity signals (compared with the signal intensity of the submandibular or parotid gland) by fat-suppressed T1-and fat-suppressed T2-weighted imaging, respectively. 16,17) In contrast, stable plaques are hard, have a thick capsule, consist primarily of fibrosis, organization, and calcification, and are reported to show iso or low signal intensity by both fat-suppressed T1-and fat-suppressed T2-weighted imaging.…”

“…16,17) In contrast, stable plaques are hard, have a thick capsule, consist primarily of fibrosis, organization, and calcification, and are reported to show iso or low signal intensity by both fat-suppressed T1-and fat-suppressed T2-weighted imaging. [15][16][17][18][19] Therefore, MRI is considered to accurately distinguish components of carotid artery plaques. We have attached importance to this qualitative assessment of plaques for the selection between CEA and CAS as a surgical treatment for carotid artery stenosis and have selected the procedure using a Sp/Sm ratio on MRI of 2 as the cut-off value as reported previously.…”

“…Since the characteristics of carotid artery plaque are an important factor of peri-procedural thromboembolism, qualitative evaluation of carotid artery plaque using MRI has recently attracted attention and has been reported to be useful. 5,6) The frequency of ischemic complications after the procedure has been reported to be high in CAS for high signalintensity unstable plaques on MRI, [7][8][9] and various embolic protection devices (EPDs) have been approved and used to prevent CAS-related embolism. However, there have been no detailed reports concerning the relationship between the MRI characteristics of carotid artery plaque and EPD selection.…”