Atherosclerosis is a significant risk factor of coronary and cerebrovascular occlusive accidents, manifested as acute myocardial infarction or ischemic stroke, which remain a leading causes of morbidity and mortality worldwide. Due to its multifactorial etiology and clinical implications, atherosclerosis has become an subject of many studies regarding a pathogenesis and natural course of the disease. According to the latest news provided by scientists from Boston University School of Medicine, the development and identification of atherosclerotic plaques at the highest risk for thrombosis can be successfully evaluated by using Magnetic Resonance Imaging (MRI).
MRI has emerged as a reliable non-invasive tool for diagnosing artherosclerosis in humans. Method has been used, alone, to identify numerous plaque features. Recently, research team under the direction of James A. Hamilton, PhD revealed that MRI might be promising imaging modality in monitoring the natural progression of atherosclerotic plaques and early detection of lesions that are evolving to become a high risk for rupture. The results were reported in the journal Atherosclerosis.
According to the study protocol atherosclerotic lesions were induced, in preclinical animal (rabbit) model of atherothrombosis, by a high cholesterol diet and aortic endothelial injury. Afterwards thrombosis was induced via two injections (repeated at 48-hour intervals) of Russell viper venom ( 0.15 mg/kg IP) and histamine (0.02 mg/kg IV). Rabbits were imaged 5 times: at baseline, 1, 2, and 3 months, and within 48 hours following pharmacological triggering for plaque disruption. Scientists analyzed following parameters: the presence of atherosclerotic plaques in rabbit’s abdominal aorta, vessel wall area (VWA), remodeling ratio (RR), plaque disruption defined as an occurrence of luminal thrombus and uptake of the paramagnetic to the atherosclerotic plaques.
Data revealed that, after 1 month following induction of atherosclerotic lesions, plaques do not differ with respect to morphological features and paramagnetic uptake. Progression of plaque vulnerable features, defined as increased VWAs, RRs, was noted after 2 months and continued it progression between 2 and 3 months. Moreover, during this time period, paramagnetic uptake, mapped ex vivo in aorta, was higher in disrupted compared to non-disrupted plaques.
Above data indicate, that MRI display high specificity in early, in vivo discrimination of vulnerable atherosclerotic plaques at a higher-risk for luminal thrombosis, in animal model. Results need to be confirmed by further testing in human population. MRI is non-invasive imaging tool, which might opens new, screening strategies of high-risk patients, enabling early detection and treatment of arthrosclerosis.
Written by: Tomasz Roman, Katarzyna Kowalczyk, Justyna Markowicz-Roman, Ewa Kramarz
Source:
1. Tuan A. Pham, Ning Hua, Alkystis Phinikaridou, Ronald Killiany, James Hamilton. Early in vivo discrimination of vulnerable atherosclerotic plaques that disrupt: A serial MRI study. Atherosclerosis Volume 244, January 2016, Pages 101–107.
2. S.B. Yeon, A. Sabir, M. Clouse, P.O. Martinezclark, D.C. Peters, T.H. Hauser, C.M. Gibson, R. Nezafat, D. Maintz, W.J. Manning, R.M. Botnar. Delayed-enhancement cardiovascular magnetic resonance coronary artery wall imaging – comparison with multislice computed tomography and quantitative coronary angiography
3. A.Blum, M. Nahir. Future non-invasive imaging to detect vascular plaque instability and subclinical non-obstructive atherosclerosis. J Geriatr Cardiol. 2013 Jun; 10(2): 178–185.
4. N. Hua et al. Identification of High-Risk Plaques by MRI and Fluorescence Imaging in a Rabbit Model of Atherothrombosis. PLoS One. 2015; 10(10): e0139833.
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