title: Feasibility and diagnostic accuracy of 16-slice multidetector computed tomography coronary angiography in 500 consecutive patients: critical role of heart rate.
abstract: OBJECTIVE
  To evaluate the feasibility and diagnostic accuracy of multidetector computed tomography coronary (MDCT) angiography applied to an unselected heart-disease population, to identify all causes of unfeasibility of exams, the distribution of artifacts in every coronary segment and their influence on diagnostic accuracy of examination.
  
  
  METHODS
  We evaluated 500 patients with different indications for invasive coronary angiography. All underwent coronary MDCT and ICA. 215 patients were pre-treated with metoprolol intravenously. In the whole population we studied native coronary arteries and in 141 cases the patency of coronary artery bypass grafts (CABG). The quality of MDCT images was graded as good, sufficient and insufficient.
  
  
  RESULTS
  We were able to evaluate the patency of all grafts, with the exception of 4 cases. Diagnostic accuracy of CABG evaluation was very high (sensitivity 100%, specificity 98.4%). In native coronary arteries the overall feasibility was 97.9%. The middle left circumflex artery, right coronary artery and posterior descending artery were the segments most often poorly visualized. The first cause of artifacts was misalignment related to high heart rate, followed by premature heart beats and calcified plaque. The population was separated into 3 groups: group 1: heart rate <55 bpm, group 2: 55-65 bpm, group 3: >65 bpm. In group 1, misalignment was significantly lower than in groups 2 and 3. On a segment-based analysis, overall feasibility was therefore significantly higher in group 1 vs group 2 and vs group 3. Images of good quality were significantly higher in group 1 (95.4%) than in group 2 (87%) and group 3 (71.8%). The higher image quality in group 1 impacts on the overall diagnostic accuracy of the exam. Indeed overall sensitivity is significantly higher in group 1 (89.5%) than in group 2 (86%) and group 3 (82.8%) and overall specificity is significantly higher in group 1 than in group 3.
  
  
  CONCLUSIONS
  Multidetector computed tomography has a high feasibility and diagnostic accuracy for the evaluation of coronary artery disease in an unselected population. Good patient preparation (optimized beta-blocker therapy, correct breathing instructions) is essential for evaluating native coronary arteries while preparation with a beta-blocker is less relevant in bypass graft patients.
authors.affiliation: Centro Cardiologico Monzino, IRCCS, Institute of Cardiology, University of Milan, Via C. Parea 4, 20138 Milan, Milan, Italy. daniele.andreini@ccfm.it
authors.forename: Daniele
authors.initials: D
authors.lastname: Andreini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Pontone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ballerini
authors.forename: Carlo
authors.initials: C
authors.lastname: Quaglia
authors.forename: Enrica
authors.initials: E
authors.lastname: Nobili
authors.forename: Alessandra
authors.initials: A
authors.lastname: Magini
authors.forename: Erika
authors.initials: E
authors.lastname: Bertella
authors.forename: Mauro
authors.initials: M
authors.lastname: Pepi
mesh_terms: D000368:Aged; D016477:Artifacts; D016009:Chi-Square Distribution; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*