title: Inter- and intra-rater reproducibility of quantitative dynamic contrast enhanced MRI using TWIST perfusion data in a uterine fibroid model.
abstract: OBJECTIVE
  To determine the reproducibility of TWIST-derived (Time-Resolved Angiography with Interleaved Stochastic Trajectories) quantitative dynamic contrast enhanced (DCE) MRI in a uterine fibroid model.
  
  
  METHODS
  The institutional review board approved this retrospective study. Dynamic contrast-enhanced TWIST datasets from 15 randomly selected 1.5 Tesla pelvic MR studies were postprocessed. Five readers recorded kinetic parameters (K(trans) [volume transfer constant], ve [extracellular extravascular space volume], kep [flux rate constant], iAUC [initial area under the gadolinium-time curve]) of the largest uterine fibroid using three region-of-interest (ROI) selection methods. Measurements were randomized and repeated three times, and measures of reproducibility were calculated.
  
  
  RESULTS
  The intra-rater coefficients of variation (CVs, brackets indicate 95% confidence intervals) varied from 4.6% to 7.6% (K(trans) 7.6% [6.1%, 9.1%], kep 7.2% [5.9%, 8.5%], ve 4.6% [3.8%, 5.4%], and iAUC 7.2% [6.1%, 8.3%]). ve was the most reproducible (P < 0.05). Inter-rater reproducibility was significantly (P < 0.05) greater for the large ROI method (range of intraclass correlation coefficients [ICCs] = 0.80-0.98 versus 0.48-0.63 [user-defined ROI] versus 0.41-0.69 [targeted ROI]). The uterine fibroid accounted for the greatest fraction of variance for the large ROI method (range across kinetic parameters: 83-98% versus 56-69% [user-defined ROI] versus 47-74% [targeted ROI]). The reader accounted for the greatest fraction of variance for the user-defined ROI method (0.4-14.1% versus 0.1-3.0% [large ROI] versus <0.1-1.5% [targeted ROI]).
  
  
  CONCLUSIONS
  Changes in TWIST-derived DCE-MRI kinetic parameters of up to 9-15% may be attributable to measurement error. Large DCE-MRI regions of interest are the most reproducible across multiple readers.
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan 48109, USA. matdaven@med.umich.edu
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Davenport
authors.forename: Tobias
authors.initials: T
authors.lastname: Heye
authors.forename: Brian M
authors.initials: BM
authors.lastname: Dale
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Horvath
authors.forename: Steven R
authors.initials: SR
authors.lastname: Breault
authors.forename: Sebastian
authors.initials: S
authors.lastname: Feuerlein
authors.forename: Mustafa R
authors.initials: MR
authors.lastname: Bashir
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Boll
authors.forename: Elmar M
authors.initials: EM
authors.lastname: Merkle
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007889:Leiomyoma / Q000150:complications / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000209:etiology / Q000473:pathology*; D015588:Observer Variation; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014594:Uterine Neoplasms / Q000150:complications / Q000473:pathology*
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine