[1.02] Catheter-based intraluminal optical coherence tomography (OCT) and endoluminal ultrasound (ELUS) in the delineation of different wall layers of porcine ureters ex vivo

Objectives Catheter-guided optical coherence tomography (OCT) is a new means of intraluminal microstructural imaging, with a spatial resolution of 10–20 μm. We compared the distinction of tissue layers of several porcine ureters ex vivo using OCT and endoluminal ultrasound (ELUS). Materials and methods Fresh porcine ureters and kidneys were obtained from the municipal slaughterhouse. They were cannulated with a 7 Fr-catheter sheath, flushed with normal saline solution, and marked on the outside with a surgical suture. Images were obtained between marked positions from within the ureter lumen by means of OCT (M1, LightLab Imaging, Inc., Westford, MA, USA) and ELUS at 40 MHz. Distinction of the urothelium, lamina propria, inner and outer muscle layer was rated as (1) possible or (0) impossible by two independent observers (O1, O2). Rates of distinction were compared between OCT and ELUS image quadrants by means of a chi-square test. Results From 224 OCT image quadrants and 144 ELUS image quadrants, OCT was found to be superior to ELUS in distinguishing any wall layers (respective chi-square, p -value: O1, 68.1051, p p p p p p p p >0.25). Conclusion Using OCT it was possible to distinguish between the different wall layers of porcine ureter ex vivo significantly better than with ELUS. The feasibility of OCT in vivo and in the presence of pathological wall thickening of the ureter remains to be demonstrated.