Vascular MRI in the Diagnosis and Therapy of the High Risk Atherosclerotic Plaque

Abstract

Disruption of a high risk plaque is known as the primary cause of cardiovascular events. Characterization of arterial wall components has become an essential adjunct in the identification of patients with plaques prone to rupture. Magnetic Resonance Imaging (MRI) has been revealed as one of the noninvasive tools possibly capable of identifying and characterizing high risk atherosclerotic plaque. MRI may facilitate diagnosis, and guide and serially monitor interventional and pharmacological treatment of atherosclerotic disease. In addition, it permits the simultaneous assessment of the anatomy, morphology, and hemodynamics for the study of flow-induced atherogenesis. It possibly will identify asymptomatic patients with subclinical atherosclerosis. This has potential significance for the improvement of strategies in primary and secondary prevention. (J Interven Cardiol 2003;16:129-142) Address for reprints: Zahi A. Fayad, Ph.D., Mount more prevalent, for instance, in the inner curve of coronary arteries, 9,10 close to side branches, 11-14 aortic arch, and in the bulb of the carotid arteries. 15,16 These are sites of flow separation 17 and oscillating shear stress, 15 suggesting that shear stress plays a role in the distribution of plaques in the vascular system. 9 Our present challenge is to develop a reliable imaging modality, preferably noninvasive, capable of characterizing the components of the atherosclerotic plaque in the different vascular beds including coronary arteries. This will permit identification and treatment of plaques at high risk of rupture and thrombosis. 18 Some of the current imaging methods include thermography, [19][20][21] Raman spectroscopy, 22 computed tomography (CT) (electron-beam CT and spiral/helical CT), 23 intravascular ultrasound (US), [24][25][26][27] and near infrared spectroscopy. 28,29 High resolution Magnetic Resonance Imaging (MRI), however, has emerged as one of the leading noninvasive imaging modalities for plaque characterization. MRI allows serial repetitions without the risk of ionizing radiation, provides high resolution images of the arterial wall and lumen, and permits early visualization of the high risk plaque. Considering the heavy toll of lives that cardiovascular diseases take worldwide, it is important to be able to detect and treat these diseases early in their course.

Noninvasive atherosclerosis imaging for predicting cardiovascular events and assessing therapeutic interventions

“…The extent of aortic plaque as assessed by TEE and MRI also correlated well [48]. A recent technique combining MRI and TEE technology involves a transesophageal MRI, which involved a probe introduced transnasally in 22 subjects, showing good correlation with the TEE values [49]. MRI of the ascending aorta in 17 patients with homozygous familial hypercholesterolemia showed increased aortic arch wall thickness relative to control subjects, which correlated with a greater CAC by EBCT [50].…”

The Vulnerable, or High-Risk, Atherosclerotic Plaque: Noninvasive MR Imaging for Characterization and Assessment

“…The detection of thrombus and the determination of its age on MR images are mainly related to the physical characteristics and visual appearance of thrombus (30), which originate from the cross linking of the fibrin strands, thrombus organization (31), the structure of hemoglobin, and the oxidation state (32). Toussaint et al (31) used the water diffusion properties of atherothrombotic tissue to distinguish fresh thrombi from 1-week-old thrombi and occluding old thrombi on MR images.…”

Lipoprotein metabolism in chronic renal insufficiency

“…We believe, therefore, that practitioners should view these algorithms with skepticism, and those who follow them should proceed with caution. Development of precise, noninvasive methods of detection and quantification of early atherosclerosis in multiple arterial beds, such as black-blood magnetic resonance imaging (MRI) [230], presents the opportunity to study this issue directly and allow treatment decisions about prolonged statin use to be based on individual ASCVD assessment of children with CKD. It must be noted that the majority of information about statin use in children with or without CKD is based only on short-term data [231].…”