Dual-source CT coronary angiography using the high-pitch mode in diagnosing the coronary artery stenosis

Objective: To evaluate the image quality,diagnostic accuracy and radiation doses for coronary artery imaging with second-generation 128-slice dual-source CT(DSCT) using the high-pitch mode.Methods: A total of 123 cases patients with suspected or known coronary artery disease were randomly divided into two groups.Group A(n = 58) underwent the adaptive prospective ECG-triggered sequence scan(CorAdpSeq) and group B(n =65) underwent the prospective high-pitch mode(pitch 3.4,Flash mode).Two experienced radiologists assessed the image quality and significant coronary stenosis(≥50%) with a double blinded fashion in a five score scale.Interobserver agreement for image quality was calculated with Cohen kappa statistics.The radiation doses values were measured.The diagnostic performance presented by DSCT in detecting stenosis ≥50% were compared with the gold standard DSA.Results: There were 1 968 segments of coronary arteries in 123 patients included in this analysis.Diagnostic image quality(score≥3) was obtained in 1920 segments(97.6%) of the coronary artery segments,which was obtained in 98.1%(910/928) of segments in group A and 97.1%(1 010/1 040) in group B respectively with no significant difference(χ2 = 0.030,P = 0.867).The mean image quality score for the whole coronary segments was(4.7 ± 0.8) in 123 patients.There was no statistical difference between mean image quality of group A(4.7 ±0.7) and group B(4.6 ±0.9)(t =0.603,P =0.548).The kappa value between two radiologists was 0.799(P 0.01) on image quality.The effective radiation dose in group B(1.08 ± 0.11) mSv was significantly(t = 11.642,P = 0.000) lower than that in group A(2.26 ± 0.49) mSv.Sensitivity and specificity were 97.6% and 97.5% per-vessel in group A;98.1%,96.5% per-vessel in group B.Conclusion: Compared with DSA both the high-pitch and CorAdpSeq mode for CTCA provide high image quality and accuracy of significant coronary stenosis,but the high-pitch mode can significantly reduce the radiation dose in the lower heart rate and regular heart rhythm.