title: Utility of magnetic resonance imaging-based finite element analysis for the biomechanical stress analysis of hemorrhagic and non-hemorrhagic carotid plaques.
abstract: BACKGROUND
  Biomechanical stress analysis has been used for plaque vulnerability assessment. The presence of plaque hemorrhage (PH) is a feature of plaque vulnerability and is associated with thromboembolic ischemic events. The purpose of the present study was to use finite element analysis (FEA) to compare the stress profiles of hemorrhagic and non-hemorrhagic profiles.
  
  
  RESULTS
  Forty-five consecutive patients who had suffered a cerebrovascular ischemic event with an underlying carotid artery disease underwent high-resolution magnetic resonance imaging (MRI) of their symptomatic carotid artery in a 1.5-T MRI system. Axial images were manually segmented for various plaque components and used for FEA. Maximum critical stress (M-Cstress(SL)) for each slice was determined. Within a plaque, the maximum M-Cstress(SL) for each slice of a plaque was selected to represent the maximum critical stress of that plaque (M-Cstress(PL)) and used to compare hemorrhagic and non-hemorrhagic plaques. A total of 62% of plaques had hemorrhage. It was observed that plaques with hemorrhage had significantly higher stress (M-Cstress(PL)) than plaques without PH (median [interquartile range]: 315 kPa [247-434] vs. 200 kPa [171-282], P=0.003).
  
  
  CONCLUSIONS
  Hemorrhagic plaques have higher biomechanical stresses than non-hemorrhagic plaques. MRI-based FEA seems to have the potential to assess plaque vulnerability.
authors.affiliation: University Department of Radiology, University of Cambridge, Cambridge Vascular Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK. us229@cam.ac.uk
authors.forename: Umar
authors.initials: U
authors.lastname: Sadat
authors.forename: Zhongzhao
authors.initials: Z
authors.lastname: Teng
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Young
authors.forename: Zhi Yong
authors.initials: ZY
authors.lastname: Li
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D020342:Finite Element Analysis; D006470:Hemorrhage / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011859:Radiography; D013312:Stress, Physiological; D013923:Thromboembolism