Optical Coherence Tomography (OCT) for Diagnosis of Early Barrett's Adeno Cancer (BC) and Early Squamous Cancer (SC)

Abstract

The high resolution of OCT suggests an applicability in the diagnosis and staging of early cancer. Aim: To develop OCT-criteria for early cancer (BC and SC) compared to non-neoplastic tissue (squamous epithelium, SE, and Barrett's esophagus, BE). Methods: The OCT system is a prototype and was developed in collaboration between LightLab Imaging, Westford, MA, and PENTAX Corporation, Japan. It uses flexible optical imaging probes (0.75 and 1.5 mm diameter) that emit near-infrared light. High-resolution real-time video images are created (radial scans up to 15 f/s, longitudinal reconstruction by using a standardized pull-back up to 55 mm in length, axial resolution 15 microns, lateral resolution 25 microns, penetration depth up to 2 mm). OCT was used to investigate early BC and SC prior to endoscopic mucosal resection (EMR), additional measurements were made of BE and SE. The histology of the resection specimen and biopsies of BE and SE served as controls. Results: 40 pt (31 m, 9 f, 64 +/− 11 y) with suspect of BC (n = 24) or SC (n = 16) were included. The penetration depth was 1.47 +/− 0.22 mm with no difference between BC and SC (p = ns). In 16 pt with SC all layers were clearly visible in non-neoplastic SE with 0.36 +/− 0.05 mm distance from epithelial surface (ES) to lamina propria (LP) and 0.78 +/− 0.10 mm from ES to the submucosa (SM). In the neoplastic area layers were only visible on 5 of 16 patients (p = 0.001); this was the case in 3/3 pt. with CIS, in 2/6 pt. with T1mucosa cancer and in 0/7 pt. with T1submucosa cancer. The distances from ES to LP (0.78 +/−0.13) and from ES to SM (1.12 +/− 0.17) were significantly increased in case of neoplasia (p < 0.05). In 20 of 24 pt with BE layers were visible in non-neoplastic areas with 0.61 +/− 0.14 mm distance from ES to LP and 1.04 +/− 0.17 mm from ES to SM. Only 21 pt finally proved to have BC. In the neoplastic area layers were only visible in 4 of 21 patients (p = 0.001); this was the case in 1/3 pt. with highgrade neoplasia, in 3/11 pt. with T1mucosa cancer and in 0/4 pt. with T1submucosa cancer. Measurement of penetration depth was not possible in BC because of diffuse light scattering. Conclusions: The prototype OCT system is able to scan larger regions for neoplasia and infiltration depth (in vivo, real-time, simultaneous longitudinal and radial scan). The penetration depth through tissue is acceptable for scanning mucosa and submucosa of SC. Improvements are necessary for satisfactory scanning of BC.