title: Plaque volume compression ratio, a novel biomechanical   index, is independently associated with ischemic   cerebrovascular events.
abstract: OBJECTIVE
  The purpose of this study was to develop a new biomechanical index for assessing the elastic characteristics of carotid plaques and to test the association between carotid plaque elasticity and ischemic cerebrovascular events (ICEs).
  
  
  METHODS
  One hundred and eighteen carotid plaques were detected with real-time three-dimensional ultrasonography in 104 patients. All patients received MRI and were divided into two groups according to the history of ICEs: patients with ICEs (n=58, including 20 patients with transient ischemic attack and 38 with ischemic stroke) and patients without ICEs (n=46). The carotid plaque volume at end diastole (Vd) and end systole (Vs) was measured by use of a TomTec (Munich, Germany) workstation. Plaque volume compression ratio (VCR) was calculated as (Vd-Vs)/Vd x 100 and the reproducibility of VCR measurement was analyzed. The carotid intima-media thickness, plaque area and plaque acoustic density were also measured. Multivariate logistic regression was used to test the association between ICEs and plaque ultrasonic parameters or traditional risk factors including age, sex, smoking, blood pressure, history of coronary heart disease, levels of serum low-density lipoprotein, triglyceride and glucose.
  
  
  RESULTS
  Satisfactory images of carotid plaques were obtained in all patients by real-time three-dimensional ultrasonography. Patients with ICEs and patients without ICEs differed significantly in VCR (22.19+/-8.42 vs. 13.95+/-7.86, P<0.01). Regression analysis revealed that systolic blood pressure, [odds ratio (OR)=1.054, 95% confidence interval (CI)=1.028-1.081, P<0.001] and VCR (OR=1.074, 95% CI=1.022-1.128, P<0.001) were associated with ICEs independently. Plaque volume had only a marginal association with ICEs (OR=1.007, 95% CI=1.000-1.013, P=0.05).
  
  
  CONCLUSIONS
  Measurement of VCR provides a noninvasive approach to the evaluation of the elasticity of carotid plaques, which is associated independently with ICEs. Thus, real-time three-dimensional ultrasonography-derived VCR holds a great potential in identifying patients with high risk of ICEs.
authors.affiliation: Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Shandong University Qilu Hospital, Jinan, Shandong, P.R. China.
authors.forename: Peng Fei
authors.initials: PF
authors.lastname: Zhang
authors.forename: Hai Jun
authors.initials: HJ
authors.lastname: Su
authors.forename: Gui Hua
authors.initials: GH
authors.lastname: Yao
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: Chun Xi
authors.initials: CX
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Shi Fang
authors.initials: SF
authors.lastname: Ding
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Yu Xia
authors.initials: YX
authors.lastname: Zhao
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D002545:Brain Ischemia / Q000150:complications* / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging; D054459:Elasticity Imaging Techniques; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors