Right phrenic nerve localization using cardiac tomography scanning: a correlation study
A Cersosimo, C De Lucia, S Zarra, E Curti, G Falasconi, D Turturiello, D Soto-Iglesias, C Gigante, D Penela, J Marti, A BerruezoAbstract
Background
The right phrenic nerve (RPN) runs in close proximity to the right atrial wall and right-sided pulmonary veins, creating a risk of iatrogenic injury during ablation procedures such as cardioneuroablation (CNA) and pulmonary vein isolation. Precise pre-procedural identification of the RPN has become increasingly feasible through multidetector computed tomography (MDCT) and dedicated 3D reconstruction.
Purpose
To assess the correlation between the trajectory of the pericardiophrenic artery (which follows the same course as the RPN) reconstructed from MDCT using iso-distance mapping, and the spatial distribution of phrenic nerve capture points obtained during electroanatomical mapping in CNA.
Methods
This prospective study included 80 consecutive patients who underwent CNA between 2021 and 2024. Right atrial anatomy was segmented from MDCT using semi-automatic thresholding, while the RPN course was obtained by manual contouring with automatic interpolation. MDCT-derived models were integrated with electroanatomical maps to generate patient-specific 3D reconstructions and iso-distance maps, representing the minimal distance between the nerve and the atrial wall. Spatial correlation with intra-procedural phrenic capture points was assessed using point-to-structure distance measurements and concordance analysis (Figure 1).
Results
80 patients (mean age 51 ± 16 years; 53% male) were included. Mapping and image integration required 12 ± 4 minutes, with 26 ± 9 phrenic capture points per patient. RPN segmentation was successful in 96% of cases. A strong spatial correspondence was observed between MDCT-derived reconstruction and the phrenic capture map, with a mean distance of 2.6 ± 0.8 mm and a phrenic imprint coefficient of 92 ± 5.
Conclusions
MDCT-based reconstruction of the RPN course shows high concordance with phrenic capture obtained during electroanatomical mapping. Integrating MDCT-derived models into CNA procedures enhances real-time awareness of nerve proximity and may improve safety, particularly when phrenic capture cannot be clinically assessed.
Figure 1.
3D right atrial reconstruction with MDCT-segmented RPN (red-white band). Left panel: phrenic capture points showing topographic concordance. Right panel: isolated nerve segmentation along the lateral right atrial wall.