Electrocardiographically triggered CT angiography of the whole aorta and coronary arteries with high-pitch dual-source CT

Objective: To investigate the feasibility of comprehensive assessment of the whole aorta and coronary arteries (CA) simultaneously with high-pitch 128-slice dual-source CT ECG-gated FLASH protocol. Methods: A total of 48 consecutive patients with suspected aortic diseases underwent CTA examination of the whole aorta and CA using a ECG-gated FLASH CT protocol (pitch=3.2) without heart rate (HR) control. Aorta, aortic valves and CA were shown with different post-processing modalities. The image quality of the aorta, aortic valves and CA was evaluated and compared according to HR (low HR group≤65 bpm, high HR group>65 bpm). The scan time, effective dose and contrast medium volume were recorded. Inter-observer differences were calculated by Kappa test. Differences between groups were analyzed by Mann-Whitney test with count data and variance test with measurement data. Results: All examinations were completed successfully. The image quality was acceptable in the aorta, aortic valve (100%, 48/48) and CA (94.0%, 551/586). Percentage of diagnostic quality images was slightly higher in low HR group (94.0%, 232/245, 93.5%, 319/341, Z=-2.504, P<0.05). Inter-reader reproducibility was 95.8% (46/48) in the aorta and aortic valve, 96.6% (566/586) in CA, yielded good agreement (Kappa=0.81 and 0.89). The mean attenuation of aorta and CA were higher than 300 HU, especially in low HR group (357.0-446.0) HU. Except proximal segment of right CA, the CNR of whole aorta and coronary arteries were significantly higher in the low HR group (24.5-29.0) than that in the high HR group (20.0-23.1, P<0.05). SNR of the whole aorta was higher in the low HR group (13.7-17.9) than the high HR group (11.5-13.9, P<0.05). The mean scan time was (1.56±0.08) s, effective dose was (4.12±1.23) mSv (2.77-6.77 mSv), and contrast medium volume was (72.8±2.1) ml. Conclusions: CT angiography of whole aorta and coronary arteries could be performed simultaneously within 2 seconds with CT ECG-gated FLASH protocol. The images were of diagnostic quality for aortic and CA disease with low dose of radiation and contrast media. However, high HR could decrease the image quality of CA.