To investigate the application effect of the “triple-low” protocol (low tube voltage, low contrast agent dose, and low injection rate) in left atrial computed tomography angiography (CTA) and evaluate its feasibility and value in reducing radiation dose and contrast agent usage while ensuring image quality.

Sixty patients who underwent left atrial CTA examinations at the Radiology Department of the First Affiliated Hospital of Nanjing Medical University from June 2024 to December 2024 were prospectively enrolled and randomly divided into a conventional protocol group (n=30) and a “triple-low” protocol group (n=30). The conventional group used 120 kV tube voltage, 0.9 mL/kg contrast agent dose, 5.0 mL/s injection rate, and filtered back projection (FBP) algorithm. The “triple-low” group used 100 kV tube voltage, 0.7 mL/kg contrast agent dose, 4.0 mL/s injection rate, and hybrid iterative reconstruction (HIR) algorithm. Subjective image scores, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), effective radiation dose (ED), and iodine intake were compared between the two groups.

Both groups met diagnostic standards for subjective image quality, with no significant intergroup differences (P>0.05). The “triple-low” group showed significantly higher mean CT values in the left atrium compared to the conventional group (P<0.01), but there were no significant differences in SNR and CNR (P>0.05). The “triple-low” group exhibited significantly lower iodine intake and effective radiation dose than the conventional group (P<0.01).

The “triple-low” protocol significantly reduces radiation dose and contrast agent usage in left atrial CTA while maintaining image quality, offering a superior imaging solution for patients and demonstrating promising clinical value.