Carotid Atherosclerotic Plaque: Noninvasive MR Characterization and Identification of Vulnerable Lesions

Abstract

Measurement of vessel stenosis by using ultrasonography or angiography remains the principal method for determining the severity of carotid atherosclerosis and the need for endarterectomy. The ipsilateral stroke rate, however--even in patients with severely stenotic vessels--is relatively low, which suggests that the amount of luminal narrowing may not represent the optimal means of assessing clinical risk. As a result, some patients may undergo unnecessary surgery. Improved imaging techniques are, therefore, needed to enable reliable identification of high-risk plaques that lead to cerebrovascular events. High-spatial-resolution magnetic resonance (MR) imaging has been described as one promising modality for this purpose, because the technique allows direct visualization of diseased vessel wall and can be used to characterize the morphology of individual atherosclerotic carotid plaques. The purpose of this report is to review the current state of carotid plaque MR imaging and the use of carotid MR to evaluate plaque morphology and composition.

Study of reproducibility of human arterial plaque reconstruction and its effects on stress analysis based on multispectral in vivo magnetic resonance imaging

“…Research on assessing plaque vulnerability has been carried out for many years using noninvasive imaging techniques such as magnetic resonance imaging (MRI) to define plaque size, shape, and components (fibrous cap, lipid core, calcification, etc.) (7). The recent development of high-resolution multispectral MRI has allowed plaque components to be visualized in vivo (8 -10).…”

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

“…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.…”

Imaging Cardiovascular Calcification

“…The carotid artery is large, superficial, and clinically important as a major source of ischemic stroke. Moreover, the carotid arteries can be imaged using phased‐array coils and well‐tested multicontrast imaging protocols such as bright‐ and black‐blood techniques 82. All of these make the carotid artery the most commonly assessed vessel in MRI studies of atherosclerosis 23, 83, 84, 85…”