Optical coherence tomography for the diagnosis of cervical intraepithelial neoplasia

Optical coherence tomography (OCT) permits high-resolution imaging of tissue subsurfaces up to 2 mm in depth. The purpose of this study was to evaluate the accuracy and reproducibility of OCT in the characterization of cervical intraepithelial neoplasia (CIN) and to distinguish between different CIN grades.

Colposcopy-guided OCT images were taken from unsuspicious and suspicious areas in women with suspected CIN. Each woman then underwent directed biopsies. All OCT images were separately evaluated by two blinded investigators and later compared to the corresponding histology based on a 6-grade classification (normal, inflammation, CIN 1, CIN 2, CIN 3, squamous carcinoma). Sensitivity and specificity of OCT in detecting CIN were determined. To assess the interobserver agreement, kappa coefficients were calculated from the ratings of each investigator for each OCT image seen.

A total of 210 OCT images were compared with the corresponding histology in 120 women undergoing colposcopy for suspected CIN. Sensitivity calculated for both investigators was 98% and 96% respectively with the threshold at CIN1 and 86% and 84% respectively with the threshold at CIN2. Thirty nine (38) false positive results reduced the specificity to 39% and 41% respectively with the threshold at CIN1. Defining the threshold at CIN2 the specificity increased to 64% and 60% respectively. Unweighted kappa from a dichotomous classification with the threshold at CIN1 was 0.69 (95% CI, 0.54-0.84) and 0.62 (95% CI, 0.51-0.73) with the threshold at CIN2.

OCT is highly sensitive in identifying pre-invasive and invasive cancer of the uterine cervix. Improvements in resolution and the development of new light sources and optics may improve the specificity as well as the differentiation of cervical dysplasia. The interobserver agreement was substantial.