title: Normalized wall index specific and MRI-based stress analysis of atherosclerotic carotid plaques: a study comparing acutely symptomatic and asymptomatic patients.
abstract: BACKGROUND
  Biomechanical stresses play an important role in determining plaque stability. Quantification of these simulated stresses can be potentially used to assess plaque vulnerability and differentiate different patient groups.
  
  
  RESULTS
  54 asymptomatic and 45 acutely symptomatic patients underwent in vivo multicontrast magnetic resonance imaging (MRI) of the carotid arteries. Plaque geometry used for nite element analysis was derived from in vivo MRI at the sites of maximum and minimum plaque burden. In total, 198 slices were used for the computational simulations. A pre-shrink technique was used to refine the simulation. Maximum principle stress at the vulnerable plaque sites (ie, critical stress) was extracted for the selected slices and a comparison was performed between the 2 groups. Critical stress in the slice with maximum plaque burden is significantly higher in acutely symptomatic patients as compared to asymptomatic patients (median, inter quartile range: 198.0 kPa (119.8-359.0 kPa) vs 138.4 kPa (83.8-242.6 kPa), P=0.04). No significant difference was found in the slice with minimum plaque burden between the 2 groups (196.7 kPa (133.3-282.7 kPa) vs 182.4 kPa (117.2-310.6 kPa), P=0.82).
  
  
  CONCLUSIONS
  Acutely symptomatic carotid plaques have significantly high biomechanical stresses than asymptomatic plaques. This might be potentially useful for establishing a biomechanical risk stratification criteria based on plaque burden in future studies.
authors.affiliation: University Department of Radiology, University of Cambridge, Cambridge, UK.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhu
authors.forename: Zhongzhao
authors.initials: Z
authors.lastname: Teng
authors.forename: Umar
authors.initials: U
authors.lastname: Sadat
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Young
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Graves
authors.forename: Zhi Yong
authors.initials: ZY
authors.lastname: Li
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
mesh_terms: D000368:Aged; D058070:Asymptomatic Diseases; D001696:Biomechanical Phenomena; D002545:Brain Ischemia / Q000209:etiology* / Q000473:pathology; D002339:Carotid Arteries / Q000473:pathology*; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012720:Severity of Illness Index; D013314:Stress, Mechanical