title: Quantitative evaluation of carotid plaque composition by in vivo MRI.
abstract: OBJECTIVE
  This study evaluates the ability of MRI to quantify all major carotid atherosclerotic plaque components in vivo.
  
  
  RESULTS
  Thirty-one subjects scheduled for carotid endarterectomy were imaged with a 1.5T scanner using time-of-flight-, T1-, proton density-, and T2-weighted images. A total of 214 MR imaging locations were matched to corresponding histology sections. For MRI and histology, area measurements of the major plaque components such as lipid-rich/necrotic core (LR/NC), calcification, loose matrix, and dense (fibrous) tissue were recorded as percentages of the total wall area. Intraclass correlation coefficients (ICCs) were computed to determine intrareader and inter-reader reproducibility. MRI measurements of plaque composition were statistically equivalent to those of histology for the LR/NC (23.7 versus 20.3%; P=0.1), loose matrix (5.1 versus 6.3%; P=0.1), and dense (fibrous) tissue (66.3% versus 64%; P=0.4). Calcification differed significantly when measured as a percentage of wall area (9.4 versus 5%; P<0.001). Intrareader and inter-reader reproducibility was good to excellent for all tissue components, with ICCs ranging from 0.73 to 0.95.
  
  
  CONCLUSIONS
  MRI-based tissue quantification is accurate and reproducible. This application can be used in therapeutic clinical trials and in prospective longitudinal studies to examine carotid atherosclerotic plaque progression and regression.
authors.affiliation: Department of Radiology, University of Washington, Seattle, Wash, USA.
authors.forename: T
authors.initials: T
authors.lastname: Saam
authors.forename: M S
authors.initials: MS
authors.lastname: Ferguson
authors.forename: V L
authors.initials: VL
authors.lastname: Yarnykh
authors.forename: N
authors.initials: N
authors.lastname: Takaya
authors.forename: D
authors.initials: D
authors.lastname: Xu
authors.forename: N L
authors.initials: NL
authors.lastname: Polissar
authors.forename: T S
authors.initials: TS
authors.lastname: Hatsukami
authors.forename: C
authors.initials: C
authors.lastname: Yuan
mesh_terms: D000368:Aged; D002340:Carotid Artery Diseases / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity