title: Diagnostic accuracy and image quality of cardiac dual-source computed tomography in patients with arrhythmia.
abstract: BACKGROUND
  Cardiac multi-detector computed tomography (MDCT) permits accurate visualization of high-grade coronary artery stenosis. However, in patients with heart rate irregularities, MDCT was found to have limitations. Thus, the aim of the present study was to evaluate the diagnostic accuracy of a new dual-source computed tomography (DSCT) scanner generation with 83 ms temporal resolution in patients without stable sinus rhythm.
  
  
  METHODS
  44 patients (31 men, mean age 67.5+/-9.2 years) without stable sinus rhythm and scheduled for invasive coronary angiography (ICA) because of suspected (n=17) or known coronary artery disease (CAD, n=27) were included in this study. All patients were examined with DSCT (Somatom Definition, Siemens). Besides assessment of total calcium score, all coronary segments were analyzed with regard to the presence of significant coronary artery lesions (>50%). The findings were compared to ICA in a blinded fashion.
  
  
  RESULTS
  During CT examination, heart rhythm was as follows: 25 patients (57%) atrial fibrillation, 7 patients (16%) ventricular extrasystoles (two of them with atrial fibrillation), 4 patients (9%) supraventricular extrasystoles, 10 patients (23%) sinus arrhythmia (heart rate variability>10 bpm). Mean heart rate was 69+/-14 bpm, median 65 bpm. Mean Agatston score equivalent (ASE) was 762, ranging from 0 to 4949.7 ASE. Prevalence of CAD was 68% (30/44). 155 segments (27%) showed "step-ladder" artifacts and 28 segments (5%) could not be visualized by DSCT. Only 70 segments (12%) were completely imaged without any artifacts. Based on a coronary segment model, sensitivity was 73%, specificity 91%, positive predictive value 63%, and negative predictive value 94% for the detection of significant lesions (>or=50% diameter stenosis). Overall accuracy was 88%.
  
  
  CONCLUSIONS
  In patients with heart rate irregularities, including patients with atrial fibrillation and a high prevalence of coronary artery disease, the diagnostic yield of dual-source computed tomography is still hampered due to a high number of segments with "step-ladder" artifacts.
authors.affiliation: Department of Diagnostic Radiology, University Hospital Tuebingen, and Department of Internal Medicine-Sports Medicine, University of Tuebingen, Germany.
authors.forename: Ilias
authors.initials: I
authors.lastname: Tsiflikas
authors.forename: Tanja
authors.initials: T
authors.lastname: Drosch
authors.forename: Harald
authors.initials: H
authors.lastname: Brodoefel
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.forename: Anja
authors.initials: A
authors.lastname: Reimann
authors.forename: Alexander
authors.initials: A
authors.lastname: Till
authors.forename: Daniel
authors.initials: D
authors.lastname: Nittka
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Kopp
authors.forename: Stephen
authors.initials: S
authors.lastname: Schroeder
authors.forename: Martin
authors.initials: M
authors.lastname: Heuschmid
authors.forename: Christof
authors.initials: C
authors.lastname: Burgstahler
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging*; D016477:Artifacts; D017023:Coronary Angiography / Q000592:standards; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards*