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.
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.


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


CONCLUSIONS
• 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.
Department of Cardiology, University of Giessen, Giessen, Germany.
Annika
A
Schuhbäck
Mohamed
M
Marwan
Sören
S
Gauss
Gerd
G
Muschiol
Dieter
D
Ropers
Christian
C
Schneider
Michael
M
Lell
Johannes
J
Rixe
Christian
C
Hamm
Werner G
WG
Daniel
Stephan
S
Achenbach
D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011829:Radiation Dosage; D011835:Radiation Protection; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol