Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

Objectives: To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA). Methods: First, a cardiac motion phantom simulating heart rates (HRs) from 60-90bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50years) undergoing clinically indicated CCTA were included. Results: In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1mm or less. Distortion increased above 1mm at HR of 80-90bpm. Patients had a mean HR of 66bpm (47-78bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73bpm. Average effective radiation dose in patients was 0.6 ± 0.3mSv. Conclusions: Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6mSv. Key points : • CCTA is feasible with the turbo high-pitch mode. • Turbo high-pitch CCTA provides diagnostic image quality up to 73bpm. • The radiation dose of high-pitch CCTA is 0.6mSv on average