Interobserver agreement for the detection of atherosclerotic plaque in coronary CT angiography: comparison of two low-dose image acquisition protocols with standard retrospectively ECG-gated reconstruction

Eur Radiol. 2012 Jul;22(7):1529-36. doi: 10.1007/s00330-012-2389-2. Epub 2012 Mar 27.


Background: We compared the interobserver variability concerning the detection of calcified and non-calcified plaque in two different low-dose and standard retrospectively gated protocols for coronary CTA.

Methods: 150 patients with low heart rates and less than 100 kg body weight were randomised and examined by contrast-enhanced dual-source CT coronary angiography (100 kV, 320 mAs). 50 patients were examined with prospectively ECG-triggered axial acquisition, 50 patients with prospectively ECG-triggered high pitch spiral acquisition, and 50 patients using spiral acquisition with retrospective ECG gating. Two investigators independently analysed the datasets concerning the presence of calcified and non-calcified plaque on a per-segment level.

Results: Mean effective dose was 1.4 ± 0.2 mSv for axial, 0.8 ± 0.07 mSv for high-pitch spiral, and 5.3 ± 2.6 mSV for standard spiral acquisition (P < 0.0001). In axial acquisition, interobserver agreement concerning the presence of atherosclerotic plaque was achieved in 650/749 coronary segments (86.8%). In high-pitch spiral acquisition, agreement was achieved in 664/748 segments (88.8%, n.s.). In standard spiral acquisition, agreement was achieved in 672/738 segments (91.0%, P < 0.0001). Interobserver agreement was significantly higher for calcified than for non-calcified plaque in all data acquisition modes.

Conclusion: Low-dose coronary CT angiography permits the detection of coronary atherosclerotic plaque with good interobserver agreement.

Key points: • Low-dose CT protocols permit coronary plaque detection with good interobserver agreement. • Image noise is a major predictor of interobserver variability. • Interobserver agreement is significantly higher for calcified than for non-calcified plaque.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cardiac-Gated Imaging Techniques / methods*
  • Contrast Media
  • Coronary Angiography / methods*
  • Coronary Artery Disease / diagnostic imaging*
  • Female
  • Humans
  • Iopamidol / analogs & derivatives*
  • Male
  • Middle Aged
  • Observer Variation
  • Radiation Dosage
  • Radiation Protection
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / methods*


  • Contrast Media
  • iomeprol
  • Iopamidol