title: Scan-rescan reproducibility of carotid atherosclerotic plaque morphology and tissue composition measurements using multicontrast MRI at 3T.
abstract: OBJECTIVE
  To evaluate interscan reproducibility of both vessel morphology and tissue composition measurements of carotid atherosclerosis using a fast, optimized, 3T multicontrast protocol.
  
  
  METHODS
  A total of 20 patients with carotid stenosis >15% identified by duplex ultrasound were recruited for two independent 3T MRI (Philips) scans within one month. A multicontrast protocol including five MR sequences was applied: TOF, T1-/T2-/PD-weighted and magnetization-prepared rapid acquisition gradient-echo (MP-RAGE). Carotid artery morphology (wall volume, lumen volume, total vessel volume, normalized wall index, and mean/maximum wall thickness) and plaque component size (lipid rich/necrotic core, calcification, and hemorrhage) were measured over two time points.
  
  
  RESULTS
  After exclusion of images with poor image quality, 257 matched locations from 18 subjects were available for analysis. For the quantitative carotid morphology measurements, coefficient of variation (CV) ranged from 2% to 15% and intraclass correlation coefficient (ICC) ranged from 0.87 to 0.99. Except for maximum wall thickness (ICC = 0.87), all ICC were larger than 0.90. For the quantitative plaque composition measurements, the ICC of the volume and relative content of lipid rich/necrotic core and calcification were larger than 0.90 with CV ranging from 22% to 32%.
  
  
  CONCLUSIONS
  The results from the multicontrast high-resolution 3T MR study show high reliability for carotid morphology and plaque component measurements. 3T MRI is a reliable tool for longitudinal clinical trials, with shorter scan time compared to 1.5T.
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington 98109, USA.
authors.forename: Feiyu
authors.initials: F
authors.lastname: Li
authors.forename: Vasily L
authors.initials: VL
authors.lastname: Yarnykh
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hatsukami
authors.forename: Baocheng
authors.initials: B
authors.lastname: Chu
authors.forename: Niranjan
authors.initials: N
authors.lastname: Balu
authors.forename: Jinnan
authors.initials: J
authors.lastname: Wang
authors.forename: Hunter R
authors.initials: HR
authors.lastname: Underhill
authors.forename: Xihai
authors.initials: X
authors.lastname: Zhao
authors.forename: Robin
authors.initials: R
authors.lastname: Smith
authors.forename: Chun
authors.initials: C
authors.lastname: Yuan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016893:Carotid Stenosis / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media