Optical coherence tomography for the detection of electrothermal ureteral injury in an ex-vivo porcine model

Significance: The current technology has limited ability to detect lateral thermal spread of injury caused by electrosurgical devices during gynecologic procedures. Aim: We aim to assess the feasibility of endoscopic optical coherence tomography (OCT) to detect electrothermal ureteral damage. Approach: Electrothermal energy was externally applied to nine explanted porcine ureters. Three segments of each ureter were treated for 5 s at low (16 W), medium (26 W), and high (36 W) powers (n=27 segments). Volumetric OCT images were acquired using a swept source OCT laser endomicroscopy system. OCT datasets were visually inspected for characterization of normal and electrothermally injured tissue architecture. Ground-truth comparisons were made with histology to validate the presence of lesions and to compare lesion size measurements using Pearson’s correlation coefficient. Three physicians were trained to identify OCT images of normal and injured ureters. Physician lesion detection accuracy was tested with 126 OCT images (63 normal and 63 injured). The effect of treatment power on lesion length as measured with OCT was compared using a one-way analysis of variance. Results: Transmural electrothermal injury was identified on OCT images for all but one histology-confirmed lesion (22/23, 95.7%). The average sensitivity and specificity for physician lesion detection were 82% and 96%, respectively. The mean lesion size measured on OCT was 3.6±1.9, 4.4±1.3, and 7.0±2.9mm for low, medium, and high powers, respectively (p=0.024). A comparison of lesion size measured on OCT and histology revealed a moderate positive correlation (r=0.65, p=0.00087). Conclusions: Endoscopic OCT could fulfill the unmet clinical need for the timely detection of electrothermal ureteral injury.