title: Dual-source versus 64-section CT coronary angiography at lower heart rates: comparison of accuracy and radiation dose.
abstract: OBJECTIVE
  To compare the diagnostic performance and radiation doses of dual-source and 64-section computed tomographic (CT) coronary angiography for the diagnosis of significant coronary stenoses in patients with heart rates of 65 beats/min or less.
  
  
  METHODS
  This retrospective study had local ethics committee approval; all patients gave written informed consent. Two hundred patients with heart rates of 65 beats/min or less were enrolled; 100 underwent dual-source and 100 underwent 64-section CT coronary angiography. Two blinded observers independently assessed image quality of all coronary segments by using a four-point scale and searched for significant (>50%) stenoses in each segment. Catheter angiography was used as the reference standard. Image noise was measured in the ascending aorta. Radiation doses were calculated.
  
  
  RESULTS
  No significant differences were found regarding sex, age, body weight, cardiovascular risk profile, prevalence of stenosis, mean and variability of heart rate, Agatston score, and image noise (all P > .1) between patients in both CT coronary angiography groups. No significant difference was found in the rate of nonassessable coronary segments between dual-source (1.0%, 14 of 1405) and 64-section CT coronary angiography (1.8%, 25 of 1387; P = .08). Motion artifacts occurred significantly more often in 64-section (21 of 25) versus dual-source (five of 14, P = .004) CT coronary angiography. Segment-based accuracy and specificity were significantly higher for dual-source versus 64-section CT coronary angiography. There was no significant difference in accuracy parameters at the per-vessel and per-patient analyses. No significant difference (P = .13) was found between the effective doses of dual-source (mean +/- standard deviation, 10.9 mSv +/- 1.1) and 64-section CT (10.4 mSv +/- 1.7) coronary angiography.
  
  
  CONCLUSIONS
  In patients with heart rates of 65 beats/min or less, the higher temporal resolution of dual-source CT coronary angiography results in improved accuracy and specificity for the diagnosis of significant stenoses on a per-segment level at a similar radiation dose, but provides a comparable diagnostic accuracy on a patient-based level as does 64-section coronary angiography.
authors: Institute of Diagnostic Radiology, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors: Stephan
authors: S
authors: Baumüller
authors: Sebastian
authors: S
authors: Leschka
authors: Lotus
authors: L
authors: Desbiolles
authors: Paul
authors: P
authors: Stolzmann
authors: Hans
authors: H
authors: Scheffel
authors: Burkhardt
authors: B
authors: Seifert
authors: Borut
authors: B
authors: Marincek
authors: Hatem
authors: H
authors: Alkadhi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D016009:Chi-Square Distribution; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide