Abstract

Background: Early detection of coronary artery disease (CAD) is important because of the high morbidity and mortality rates. As invasive coronary angiography (ICA) is an invasive procedure, an alternative diagnostic method; coronary computed tomography angiography (CTA), has become more widely used by the improvements in detector technology.

Aims: In this study, we aimed to examine the accuracy and image quality of high-pitch 128-slice dual-source CTA taking the ICA as reference technique. We also aimed to compare the accuracy and image quality between different heart rate groups of >70 beates per minute (bpm) and ≤70 bpm.

Study Design: Retrospective cross-sectional study.

Methods: Among 450 patients who underwent coronary CTA with the FLASH spiral technique, performed with a second generation dual-source computed tomography device with a pitch value of 3.2, 102 patients without stent and/or bypass surgery history and clinically suspected coronary artery disease who underwent ICA within 15 days were enrolled. Image quality was assessed by two independent radiologists using a 4-point scale (1=absence of any artifacts- 4=non-evaluable). A stenosis >50% was considered significant on a per-segment, per-vessel, and per-patient basis and ICA was considered the reference method. Radiation doses were determined using dose length product (DLP) values detected by the computed tomography (CT) device. In addition, patients were classified into two groups according to their heart rates as ≤70 bpm (73 patients) and >70 bpm (29 patients). The relation between the diagnostic accuracy and heart rate groups were evaluated.

Results: Overall, 1495 (98%) coronary segments were diagnostic in 102 patients (32 male, 70 female, mean heart rate: 65 bpm). There was a significant correlation between image quality and mean heart rate in the right coronary artery (RCA) segments. The effective radiation dose was 0.98±0.09 mili Sievert (mSv). On a per-patient basis, sensitivity, specificity, and positive and negative predictive values were 93.8%, 88.8%, 93.8% and 88.8%, respectively. These values were also similar in per-vessel and per-segment basis. Two different groups categorized by mean heart rate had almost similar results in terms of the diagnostic power of dual-source CTA.

Conclusion: CTA with a high pitch value is a reliable, non-invasive diagnostic method that can CAD with low radiation doses not only in patients with a heart rate below 70 bpm, but also in patients with higher heart rates.