Accuracy of real-time vs. blinded offline diagnosis of neoplastic colorectal polyps using probe-based confocal laser endomicroscopy: a pilot study

Background and study aims: Probe-based confocal laser endomicroscopy (pCLE) is a new imaging modality that enables histological examination of gastrointestinal mucosa during endoscopic procedures. Most studies have evaluated offline interpretation of pCLE images. In clinical practice, real-time interpretation is necessary to assist decision- making during the procedure. The aim of this pilot study was to compare the accuracy of real-time pCLE diagnosis made during the procedure with that of blinded offline interpretation to provide accuracy estimates that will aid the planning of future studies. Patients and methods: pCLE was performed in patients undergoing screening and surveillance colonoscopy. Once a polyp had been identified, one endoscopist analyzed pCLE images during the procedure and made a provisional "real-time" diagnosis. Saved video recordings were de-identified, randomized, and reviewed "offline" 1 month later by the same endoscopist, who was blinded to the original diagnoses. Results: Images from a total of 154 polyps were recorded (80 neoplastic, 74 non-neoplastic). The overall accuracy of real-time pCLE diagnosis (accuracy 79%, sensitivity 81%, specificity 76%) and offline pCLE diagnosis (83%, 88%, and 77%, respectively) for all 154 polyps were similar. Among polyps < 10mm in size, the accuracy of real-time interpretation was significantly lower (accuracy 78%, sensitivity 71%, specificity 83%) than that of offline pCLE interpretation (81%, 86%, 78%, respectively). For polyps >= 10mm, the accuracy of pCLE diagnosis in real-time was better (accuracy 85%, sensitivity 90%, specificity 75%) than offline pCLE diagnosis (81%, 97%, and 50%, respectively). Conclusions: These results suggest that real-time and offline interpretations of pCLE images are moderately accurate. Real-time interpretation is slightly less accurate than offline diagnosis, but overall both are comparable. Additionally, there was contrasting accuracy between the two methods for small and large polyps.