1.01] Comparative morphometry in porcine ureteral wall specimens ex vivo using catheter-based intraluminal optical coherence tomography (OCT) and histology

Abstract

Rationale and objectives In order to assess the reliability of the delineation of cross-sectional optical coherence tomography (OCT) images, we compared the width of different tissue layers of the wall of upper porcine ureters ex vivo as measured on OCT images with the corresponding whole mount histology microscopy sections. Materials and methods Fifteen specimens of porcine upper ureters were flushed with normal saline solution prior to imaging from the inside by means of an OCT catheter (diameter: 0.014 in, OCT wavelength: 1300±20 nm) at marked locations. Ring-shaped ureter specimens of 3 mm width were fixed in 4% formalin, cut, whole-mounted, and stained with H&E. OCT images (M1, LightLab Imaging, Inc., Westford, MA, USA) of appropriate thickness of urothelium, lamina propria, and muscle layer of the ureteral wall were compared with corresponding light microscopy slides (Axioplan2, Carl Zeiss Corporation, Jena, Germany) by two independent observers (O1, O2) applying Bland–Altmann plots and t -tests for paired data. Results When compared with histological slides, respective OCT measurements by O1 and O2 overestimated the width of the urothelium by 0.02±0.01 and 0.02±0.01 mm ( p =0.0014 and 0.0002), lamina propria by 0.02±0.05 and 0.03±0.03 mm ( p =0.2047 and 0.0025), and muscle layer by 0.26±0.15 and 0.07±0.05 mm ( p = Conclusion Intraluminal OCT reliably delineates the urothelium and lamina propria of the normal ureteral wall in porcine specimens ex vivo when compared with the corresponding histology. The outer boundaries of the muscle layer of the ureteral wall appear to be beyond reliable reach of OCT.