Quantification of carotid plaque lipid content with magnetic resonance T2 mapping in patients undergoing carotid endarterectomy

• Published in: PloS one Vol. 12; no. 7; p. e0181668
• Main Authors: Alkhalil, Mohammad, Biasiolli, Luca, Chai, Joshua T., Galassi, Francesca, Li, Linqing, Darby, Christopher, Halliday, Alison, Hands, Linda, Magee, Timothy, Perkins, Jeremy, Sideso, Ed, Jezzard, Peter, Robson, Matthew D., Handa, Ashok, Choudhury, Robin P.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26.07.2017; Public Library of Science (PLoS)
• Subjects: Aged; Aged, 80 and over; Agglomeration; Analysis; Arteries; Atherosclerosis; Bifurcations; Biology and Life Sciences; Care and treatment; Carotid arteries; Carotid Arteries - chemistry; Carotid Arteries - diagnostic imaging; Carotid Arteries - surgery; Carotid artery; Carotid artery diseases; Carotid Stenosis - diagnostic imaging; Carotid Stenosis - metabolism; Correlation; Endarterectomy; Endarterectomy, Carotid - methods; Female; Humans; Information processing; Lipid Metabolism; Lipids; Lipids - analysis; Magnetic resonance; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Mapping; Medicine; Medicine and Health Sciences; Middle Aged; Neurosciences; NMR; Nuclear magnetic resonance; Patients; Plaque, Atherosclerotic - diagnostic imaging; Plaque, Atherosclerotic - metabolism; Plaque, Atherosclerotic - surgery; Research and Analysis Methods; Risk factors; Stenosis; Stroke; Subgroups; Surgery; Ultrasonic imaging; Ultrasonography; Ultrasound
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0181668

Techniques to stratify subgroups of patients with asymptomatic carotid artery disease are urgently needed to guide decisions on optimal treatment. Reliance on estimates of % luminal stenosis has not been effective, perhaps because that approach entirely disregards potentially important information on the pathological process in the wall of the artery. Since plaque lipid is a key determinant of plaque behaviour we used a newly validated, high-sensitivity T2-mapping MR technique for a systematic survey of the quantity and distribution of plaque lipid in patients undergoing endarterectomy. Lipid percentage was quantified in 50 carotid endarterectomy patients. Lipid distribution was tested, using two imaging indices (contribution of the largest lipid deposit towards total lipid (LLD %) and a newly-developed LAI 'lipid aggregation index'). The bifurcation contained maximal lipid volume. Lipid percentage was higher in symptomatic vs. asymptomatic patients with degree of stenosis (DS ≥ 50%) and in the total cohort (P = 0.013 and P = 0.005, respectively). Both LLD % and LAI was higher in symptomatic patients (P = 0.028 and P = 0.018, respectively), suggesting that for a given plaque lipid volume, coalesced deposits were more likely to be associated with symptomatic events. There was no correlation between plaque volume or lipid content and degree of luminal stenosis measured on ultrasound duplex (r = -0.09, P = 0.53 and r = -0.05, P = 0.75), respectively. However, there was a strong correlation in lipid between left and right carotid arteries (r = 0.5, P <0.0001, respectively). Plaque lipid content and distribution is associated with symptomatic status of the carotid plaque. Importantly, plaque lipid content was not related to the degree of luminal stenosis assessed by ultrasound. Determination of plaque lipid content may prove useful for stratification of asymptomatic patients, including selection of optimal invasive treatments.