Low-dose CT coronary angiography with a novel intracyclemotion-correction algorithm in patients with high heart rate or heart rate variability

Aims: Motion artefacts due to high or irregular heart rate (HR) are common limitations of coronary computed tomography (CT) angiography (CCTA). The aim of the study was to evaluate the impact of a new motion-correction (MC) algorithm used in conjunction with low-dose prospective ECG-triggering CCTA on motion artefacts, image quality, and coronary assessability. Methods and results: Among 380 patients under going CCTA for suspected CAD, weselected 120 patients with pre-scanning HR.70 bpm or HR variability (HRv) >10 bpm during scanning irrespective of pre-scanning HR or both conditions. In patients with prescanning HR <65 or ≥65 bpm, prospective ECG triggering with padding of 80 ms (58 cases) or padding of 200 ms (62 cases) was used, respectively. Mean pre-scanning HR and HRvwere 70±7 and 10.9±4 bpm, respectively. Overall, the mean effective dose was 3.4±1.3 mSv, while a lower dose (2.4±0.9 mSv) was measured for padding of 80 ms. In a segment-based analysis, coronary assessability was significantly higher (P < 0.0001) with MC (97%) when compared with standard (STD) reconstruction (81%) due to a significant reduction (P < 0.0001) in severe artefacts (54 vs. 356 cases, respectively). An artefact sub-analysis showed significantly lower number of motion artefacts and artefacts related to chest movement with MC (16 and 4 cases) than with STD reconstruction (286 and 24 cases, P < 0.0001 and P < 0.05, respectively). The number of coronary segments ranked among those of excellent image quality was significantly higher with MC (P < 0.001). Conclusions: The MC algorithm improves CCTA image quality and coronary assessability in patients with high HR and HRv, despite low radiation dose.