title: Right coronary artery flow velocity and volume assessment with spiral K-space sampled breathhold velocity-encoded MRI at 3 tesla: accuracy and reproducibility.
abstract: OBJECTIVE
  To evaluate accuracy and reproducibility of flow velocity and volume measurements in a phantom and in human coronary arteries using breathhold velocity-encoded (VE) MRI with spiral k-space sampling at 3 Tesla.
  
  
  METHODS
  Flow velocity assessment was performed using VE MRI with spiral k-space sampling. Accuracy of VE MRI was tested in vitro at five constant flow rates. Reproducibility was investigated in 19 healthy subjects (mean age 25.4 +/- 1.2 years, 11 men) by repeated acquisition in the right coronary artery (RCA).
  
  
  RESULTS
  MRI-measured flow rates correlated strongly with volumetric collection (Pearson correlation r = 0.99; P < 0.01). Due to limited sample resolution, VE MRI overestimated the flow rate by 47% on average when nonconstricted region-of-interest segmentation was used. Using constricted region-of-interest segmentation with lumen size equal to ground-truth luminal size, less than 13% error in flow rate was found. In vivo RCA flow velocity assessment was successful in 82% of the applied studies. High interscan, intra- and inter-observer agreement was found for almost all indices describing coronary flow velocity. Reproducibility for repeated acquisitions varied by less than 16% for peak velocity values and by less than 24% for flow volumes.
  
  
  CONCLUSIONS
  3T breathhold VE MRI with spiral k-space sampling enables accurate and reproducible assessment of RCA flow velocity.
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands. j.j.m.westenberg@lumc.nl
authors.forename: Anne
authors.initials: A
authors.lastname: Brandts
authors.forename: Stijntje D
authors.initials: SD
authors.lastname: Roes
authors.forename: Joost
authors.initials: J
authors.lastname: Doornbos
authors.forename: Robert G
authors.initials: RG
authors.lastname: Weiss
authors.forename: Albert
authors.initials: A
authors.lastname: de Roos
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
authors.forename: Jos J M
authors.initials: JJ
authors.lastname: Westenberg
mesh_terms: D000328:Adult; D016477:Artifacts; D001783:Blood Flow Velocity; D001810:Blood Volume; D003331:Coronary Vessels / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009929:Organ Size; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity