Spatial association between CT-derived myocardial deformation and stereotactic radioablation targets in ventricular
Xinyu Lu1, Vera Maslova2, Melanie Grehn3
1Institute of Robotics and Cognitive Systems, University of Lübeck, Lübeck, 23562, Schleswig-Holstein, Germany.
Background:
Stereotactic arrhythmia radioablation (STAR) targets are typically defined by electroanatomical mapping and imaging-based substrate characterisation, yet their spatial relationship to mechanically derived deformation abnormalities remains incompletely understood.
Objective:
To evaluate the spatial association between CT-derived end-diastolic-end-systolic (ED-ES) radial deformation abnormalities and clinically defined STAR targets.
Methods:
In 9 patients undergoing STAR, 3-dimensional left ventricular shells were reconstructed from ECG-gated contrast-enhanced CT. Radial deformation between ED-ES was estimated from the inter-phase displacement field, and abnormal regions were defined by a patient-specific threshold at the lower 10th percentile of voxel-wise radial deformation. STAR targets were transferred from voltage maps onto the CT geometry. Spatial relationships were assessed using centroid distance, mean surface distance, volumetric overlap, and segment-level concordance.
Results:
Eleven abnormal radial deformation regions and 11 STAR targets were identified. At the segment level, radial deformation discriminated target-positive segments (area under curve [AUC], 0.80; 95% confidence intervals [CI], 0.73-0.88) significantly better than longitudinal deformation (AUC, 0.71; 95% CI, 0.66-0.76; DeLong P < .001). The median centroid distance between abnormal regions and STAR targets was 20.4 mm (interquartile range [IQR], 15.4-33.7), and the median mean surface distance was 6.0 mm (IQR, 2.8-9.7). Partial volumetric overlap occurred in 9 of 11 deformation-defined regions, and 10 of 11 STAR targets overlapped with at least 1 deformation-defined abnormality. Abnormal radial deformation was present in 18 of 21 target-positive segments (86%) vs 41 of 129 target-negative segments (32%).
Conclusion:
CT-derived ED-ES radial deformation abnormalities show a substantial spatial association with clinically defined STAR targets, alongside partial discordance, and may complement substrate characterisation in patients undergoing STAR.
