CT angiography for TAVI planning: Image quality with constant and variable contrast injection rates

Background: To assess the image quality of computed tomography angiography (CTA) with variable-rate and constant-rate contrast injection protocols for transcatheter aortic valve implantation (TAVI) planning. Methods: Ninety-seven patients undergoing 256-row multi-detector computed tomography (MDCT) for TAVI planning were included. A variable-rate contrast injection protocol was employed for 46 patients (study group), while 51 patients underwent a standard constant-rate contrast injection protocol (control group). Objective image quality metrics, including CT value, standard deviation (SD), beam hardening artifact (BHA), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), were evaluated for the right coronary artery (RCA), left anterior descending artery (LAD), left circumflex artery (LCX), right atrium (RA), and aorta. Subjective image quality, including diagnostic image quality and visualization of the aorta and major coronary artery branches, was assessed by two radiologists. Results: There were no significant differences in CT values between the study and control groups for RCA, LAD, LCX, RA, and aorta. Coronary artery SD in the study group was significantly lower than in the control group (39.77 ± 8.00 vs. 65.06 ± 18.09, P < 0.01). Coronary artery and aorta SNR in the study group were significantly higher than in the control group ( P < 0.01 for both). Coronary artery CNR in the study group was significantly lower than in the control group ( P < 0.01), while aorta CNR did not differ significantly between groups. Subjective image quality scores for coronary artery visualization were significantly higher in the study group (3.98 ± 0.71 vs. 3.41 ± 0.68, P = 0.021, ICC = 0.87). Conclusion: Compared to the standard CTA protocol, the variable-rate contrast injection protocol reduces hardening artifacts and provides high-quality images for accurate TAVI planning.