Assessment of carotid plaque vulnerability using structural and geometrical determinants.
BACKGROUND
Because many acute cerebral ischemic events are caused by rupture of vulnerable carotid atheroma and subsequent thrombosis, the present study used both idealized and patient-specific carotid atheromatous plaque models to evaluate the effect of structural determinants on stress distributions within plaque.


RESULTS
Using a finite element method, structural analysis was performed using models derived from in vivo high-resolution magnetic resonance imaging (MRI) of carotid atheroma in 40 non-consecutive patients (20 symptomatic, 20 asymptomatic). Plaque components were modeled as hyper-elastic materials. The effects of varying fibrous cap thickness, lipid core size and lumen curvature on plaque stress distributions were examined. Lumen curvature and fibrous cap thickness were found to be major determinants of plaque stress. The size of the lipid core did not alter plaque stress significantly when the fibrous cap was relatively thick. The correlation between plaque stress and lumen curvature was significant for both symptomatic (p=0.01; correlation coefficient: 0.689) and asymptomatic patients (p=0.01; correlation coefficient: 0.862). Lumen curvature in plaques of symptomatic patients was significantly larger than those of asymptomatic patients (1.50+/-1.0 mm(-1) vs 1.25+/-0.75 mm(-1); p=0.01).


CONCLUSIONS
Specific plaque morphology (large lumen curvature and thin fibrous cap) is closely related to plaque vulnerability. Structural analysis using high-resolution MRI of carotid atheroma may help in detecting vulnerable atheromatous plaque and aid the risk stratification of patients with carotid disease.
Li
Zhi-Yong
ZY
University Department of Radiology, Box 219, Level 5, Cambridge University Hospitals Foundation Trust, Cambridge CB2 2QQ, UK. ZYL22@cam.ac.uk
Tang
Tjun
T
U-King-Im
Jean
J
Graves
Martin
M
Sutcliffe
Michael
M
Gillard
Jonathan H
JH
D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000473:pathology / Q000503:physiopathology; D016893:Carotid Stenosis / Q000473:pathology* / Q000503:physiopathology; D003324:Coronary Artery Disease / Q000473:pathology* / Q000503:physiopathology; D004548:Elasticity; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000473:pathology* / Q000503:physiopathology; D013314:Stress, Mechanical