title: Automated cardiac phase selection with 64-MDCT coronary angiography.
abstract: OBJECTIVE
  The aim of this study was to assess three different phase-selection methods for obtaining optimal CT coronary artery image quality.
  
  
  METHODS
  ECG-gated CT coronary angiography scans of 40 patients (23 men, 17 women; mean age, 56 years) were retrieved. The patient group was composed of 20 consecutive patients with heart rates < or = 65 beats per minute (bpm) and 20 consecutive patients with heart rates > 65 bpm. Three phase-selection methods were evaluated: fixed phase selection, manual phase selection, and automated phase selection. Two scoring systems were used to evaluate diagnostic quality: scoring of axial images on a 5-point scale and scoring of multiplanar reconstructions (MPRs) on a forced-choice 3-point preference scale. Differences were tested by Wilcoxon's signed rank test for the entire patient group and the two subgroups including patients with heart rates < or = 65 bpm and those with heart rates > 65 bpm.
  
  
  RESULTS
  Axial image evaluation of the entire patient group showed statistically significant superior image quality for the manual phase-selection method compared with the predefined phase-selection method and no statistically significant differences were found for the other comparisons. Analysis at heart rates < or = 65 bpm showed no significant differences between phase-selection methods. Analysis at heart rates > 65 bpm showed the best results for the automated phase-selection method, and image quality was significantly better for the automated and manual phase-selection methods than for the predefined phase-selection method.
  
  
  CONCLUSIONS
  The automated phase-selection method accurately detects the optimal diagnostic phase for CT coronary artery evaluation and has the potential to reduce operator time needed for image reconstruction.
authors.affiliation: Department of Radiology, University Medical Center Leiden, PO Box 9600, 2300 RC Leiden, The Netherlands. r.m.s.joemai@lumc.nl
authors.forename: Raoul M S
authors.initials: RM
authors.lastname: Joemai
authors.forename: Jacob
authors.initials: J
authors.lastname: Geleijns
authors.forename: Wouter J H
authors.initials: WJ
authors.lastname: Veldkamp
authors.forename: Albert
authors.initials: A
authors.lastname: de Roos
authors.forename: Lucia J M
authors.initials: LJ
authors.lastname: Kroft
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001185:Artificial Intelligence; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*