Abstract
Atherosclerotic plaque burden has a strong correlation with plaque vulnerability. Three-dimensional (3D) volumetric assessment of atherosclerotic plaques has been suggested as an accurate method of quantifying plaque burden but has not been performed. In this study we use high-resolution magnetic resonance (MR) imaging to compare 3D volume differences of asymptomatic and acutely symptomatic carotid plaques (i.e. had cerebrovascular ischaemic symptoms within the previous 72 h of MR imaging). One hundred patients (46 acutely symptomatic and 54 asymptomatic) with atherosclerotic carotid artery disease underwent carotid MR imaging. Manual segmentation of plaque components was done to delineate lipid, fibrous tissue and plaque haemorrhage (PH). 3D-volume reconstruction of plaque components was done and used for comparison. Acutely symptomatic plaques had a lower normalized wall index and normalized volume index than the asymptomatic group (P = 0.04 and 0.01 respectively). Median percentage lipid volume was higher for asymptomatic plaques (28 vs. 5%, P = 0.004). However, the median percentage volume and prevalence of PH was higher in the acutely symptomatic group (P = 0.01 and 0.02 respectively). Acutely symptomatic plaques have less lipid content immediately after the acute event than asymptomatic plaques. This is most likely because of the escape of lipid-rich atheromatous debris into the blood stream at the time of plaque rupture. Due to this paradox, “high” lipid content of a plaque may not be a reliable feature of estimating its vulnerability immediately following the acute event. PH, which is prevalent and consistent in such plaques, may be a better indicator of plaque vulnerability during that period.
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Acknowledgments
Dr. Umar Sadat is supported by a Medical Research Council UK & Royal College of Surgeons of England Joint Clinical Research Training Fellowship. This research has also been supported by a Biomedical Research Centre National Institute of Health Research (BRC NIHR) grant.
Author Contributions
US developed the hypothesis, designed the study, performed the study, analysed the bulk of the data and wrote the manuscript; ZT performed the volumetric analysis of the entire data; VEY contributed to the morphological MR data analysis; MJG wrote the MR pulse sequences for this study; JHG confirmed the accuracy of the MR data and supervised the entire project and writing of the manuscript.
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Sadat, U., Teng, Z., Young, V.E. et al. Three-dimensional volumetric analysis of atherosclerotic plaques: a magnetic resonance imaging-based study of patients with moderate stenosis carotid artery disease. Int J Cardiovasc Imaging 26, 897–904 (2010). https://doi.org/10.1007/s10554-010-9648-6
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DOI: https://doi.org/10.1007/s10554-010-9648-6