Objectives To evaluate the feasibility and imaging quality of double prospectively ECG-triggered high-pitch spiral acquisition mode (double flash mode) for coronary computed tomography angiography (CTCA) in patients with atrial fibrillation (AF).

Methods 47 patients (11 women, 36 men; mean age 64.5 ± 12.1 years) were enrolled for CTCA examinations using a dual-source CT with 2×128 × 0.6 mm collimation, 0.28 s rotation time and a pitch of 3.4. Double flash mode was prospectively triggered first at 60% and later at 30% of the R-R interval within two cardiac cycles. Image quality was evaluated using a four-point scale (1 = excellent, 4 = non-assessable).

Results From 672 coronary artery segments, 77.5% (521/672) was rated as score of 1, 20.8% (140/672) as score of 2, 1.2% (8/672) as score of 3 and 0.4% (3/672) was rated as ‘non-assessable’. The average image quality score was 1.25 ± 0.38 on a per segment basis. Mean dose-length product (DLP) for CTCA was 92.6 ± 28.2 mGy·cm, the effective dose was 1.30 ± 0.39 mSv (0.64-1.97 mSv).

Conclusions In patients with AF, double prospectively ECG-triggered high-pitch spiral acquisition mode could be a feasible and valuable scan mode for CTCA with a consistent dose below 2 mSv as well as diagnostic imaging quality.