The Single-Delayed-Phase Contrast Computed Tomography Before Ablation to Reduce Radiation Exposure Without...

Early-phase contrast-enhanced CT (CCT) is often used to plan and guide catheter ablation for atrial fibrillation (AF), and delayed-phase images can be used to detect or exclude left atrial appendage (LAA) thrombosis. However, dual-phase CCT is associated with concerns about radiation exposure; hence, this study aimed to evaluate whether single-delayed-phase images can provide sufficient preoperative information while minimizing radiation exposure.

A total of 102 patients who underwent dual-phase CCT were analyzed for pulmonary vein (PV) anatomy and LAA thrombus detection. The decrease in image quality due to the difference between early and delayed phases in 3D reconstruction did not pose a problem regarding anatomical evaluation. The PV anatomy was classified as typical or atypical, and 399 PVs were analyzed. Atypical PVs included 17 cases, with consistent anatomical details across the early and delayed phases. The mean discrepancy in PV diameter between the two phases and the correlation coefficient for the coronal view was 0.78 ± 0.16 mm, r = 0.91, and for the axial view, 0.79 ± 0.15 mm, r = 0.93. The LAA thrombi were observed in three patients, and no thrombus was overestimated in the delayed phase. The total exposure dose was 2320.1 ± 1031.0 mGy-cm in the dual-phase, 1443.3 ± 578.5 mGy-cm in the single early phase, and 876.8 ± 526.6 mGy-cm in the single delayed phase. Radiation doses were significantly lower in single-phase imaging than in dual-phase.

The single-delayed-phase CCT provides accurate anatomical and thrombus evaluations while significantly reducing radiation exposure. This approach could be a safer alternative for pre-ablation assessment without compromising diagnostic reliability.

The University of Occupational and Environmental Health ethics committee approved the study (UOEHCRB22-067).