Comparison of Radiation Exposure between Computed Tomography Angiography and Invasive Catheter Angiography in the Pre-operative Assessment of Patients with Tetralogy of Fallot

Objectives: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease in infancy, frequently requiring early surgical repair. Detailed pre-operative imaging is essential for assessing cardiovascular and extracardiac anatomy to guide surgical planning. While conventional invasive catheter angiography (ICA) has traditionally been used for this purpose, computed tomography angiography (CTA) has emerged as a promising non-invasive alternative with lower risk, shorter procedure times, and reduced radiation exposure. Given the vulnerability of pediatric patients, optimizing radiation dose and understanding its determinants – such as body size – are critical. The objective of the study is to compare radiation exposure, contrast agent usage, and procedural duration between CTA and ICA in the pre-operative evaluation of TOF patients under 1 year of age and to evaluate the correlation between patient anthropometric measurements and radiation dose. Methods: This retrospective single-center study included 120 TOF patients who underwent complete surgical repair between 2021 and 2024. Seventy-four patients underwent CTA and 46 underwent ICA. Data on radiation dose, contrast volume, and procedure time were collected. Correlations between effective dose and patient age, weight, height, and BMI were analyzed. Results: CTA significantly reduced effective radiation dose (1.21±0.19 mSv) compared to ICA (5.28±1.71 mSv, p<0.01), required less contrast agent (8.02±2.38 cc vs. 38.8±13.01 cc), and had a shorter procedure time (3.1±0.58 min vs. 21.03±10.79 min; p<0.001). Radiation dose was positively correlated with weight (CTA: r=0.41, p=0.0006; ICA: r=0.52, p=0.0009), height (CTA: r=0.32, p=0.0012; ICA: r=0.24, p=0.0014), and BMI (CTA: r=0.35, p=0.0008; ICA: r=0.39, p=0.0053), while no significant correlation was observed with age. Conclusion: CTA is a safe, non-invasive, and time-efficient imaging modality for the pre-operative evaluation of TOF patients, offering significant reductions in radiation dose and contrast use compared to ICA. The observed correlation between radiation dose and body size underscores the need for individualized imaging protocols in pediatric practice.