title: Intra- and interstudy reproducibility of coronary artery diameter measurements in magnetic resonance coronary angiography.
abstract: OBJECTIVE
  To determine the intra- and interstudy reproducibility of right coronary artery diameter assessment using serial magnetic resonance (MR) coronary angiography.
  
  
  METHODS
  Two-dimensional (2D) navigator-gated segmented fast low angle shot (FLASH) images of the proximal right coronary artery were acquired three times in 11 healthy volunteers, the first two times in the same study session and the third time after repositioning the subject in the scanner. Coronary artery diameters were determined using automated segmentation software and intra- and interstudy reproducibility calculated as the standard deviation (SD) of the signed differences between measurements within and between study sessions, respectively. The reproducibility of the segmentation software was determined by repeated analysis of each individual scan.
  
  
  RESULTS
  One subject was excluded from the study due to poor-quality images. In the remaining 10 subjects, the mean (+/- SD) intrastudy difference in coronary artery diameters was -0.05 +/- 0.12 mm, a value that is very similar to between-frame (same-film) differences reported in quantitative coronary angiography (QCA). The mean (+/- SD) interstudy difference in coronary artery diameters was 0.16 +/- 0.43 mm, although this was greatly skewed by one subject with poor image plane repositioning. Excluding that subject resulted in a mean (+/- SD) interstudy difference of 0.04 +/- 0.20 mm. The reproducibility of the segmentation software was excellent, with the mean difference between repeat analyses of the images being 0.00 +/- 0.03 mm.
  
  
  CONCLUSIONS
  The intrastudy variability of coronary artery diameter measurements is low, potentially allowing MR coronary angiography to be used as a tool for the noninvasive assessment of serial changes following pharmacological intervention. A major contributing factor to this is the high reproducibility of the segmentation software. Interstudy variability is approximately three times the intrastudy variability.
authors.affiliation: Royal Brompton and Harefield NHS Trust, London, UK. j.keegan@rbh.nthames.nhs.uk
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keegan
authors.forename: Paramate
authors.initials: P
authors.lastname: Horkaew
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Buchanan
authors.forename: Trevor S
authors.initials: TS
authors.lastname: Smart
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
authors.forename: David N
authors.initials: DN
authors.lastname: Firmin
mesh_terms: D000328:Adult; D001158:Arteries / Q000033:anatomy & histology; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results