Evaluation of CAD-EYE/SCALE-EYE for Detection, Classification, and Measurement of Colorectal Polyps: a Prospective Study

The investigators hypothesize that the clinical implementation of an AI system is an optimal tool to monitor, audit and improve the detection and classification of polyps during colonoscopy. The purpose of this prospective clinical cohort study is to evaluate the performance of the SCALE-EYE virtual scale for measuring polyp size when used during live colonoscopies. The investigators also wish to evaluate CAD-eye for detection and classification of polyp histology. It is hypothesized that CAD-eye and SCALE-EYE can function in real-time practice with high accuracy.

Detailed Description:

This study will be conducted in several phases: phase 1 will evaluate the feasibility of using CAD-eye in real-time practice, training endoscopists to work with this platform, obtaining preliminary data on relative size measurement accuracy when using scale eye, testing feasibility of fresh polyp specimen size measurement and determining the sample size and reference standard for evaluating SCALE-EYE during the subsequent phases of the study in randomized controlled trials. Phase 2 will evaluate relative size measurement accuracy of SCALE-EYE compared to visual size estimation and CADe/CADx performance in a randomized controlled trial. Scale-eye will further be validated through video-based analysis comparing different size measurement methods (scale eye, snare, forceps, visual assessment) with different groups of endoscopists (experts, staff gastroenterologists, trainees evaluating videos showing video sequences that show the polyps either with scale eye, visual or instrument information. Furthermore, fresh specimen size measurement and pathology-based size (including different ways to prepare specimens for pathology sectioning) will be evaluated for agreement between size measurement methods and tissue shrinkage effects. Phase 3 will evaluate relative size measurement accuracy of SCALE-EYE compared to snare-based size estimation.

Eligible patients will be adults (aged 45 to 80 years) referred to CHUM for diagnostic, screening or surveillance colonoscopy. Patients will undergo colonoscopies using CAD-eye, and the size of all polyps detected will be estimated by different subjective and objective methods. All polyp size measurements will be videorecorded. Video recordings with different measurement instruments (forceps, snare, scale eye, visual assessment) will be assessed with different groups of endoscopists (experts, staff gastroenterologists, trainees) for size measurements through online video presentations in a randomized order. The main results of this study are to evaluate the relative accuracy of SCALE-EYE for polyp size estimation and the adenoma detection rates, sensitivity, specificity, NPV for CAD-eye for polyp detection and classification. We will also calculate other characteristics of CAD-eye and SCALE-EYE tests, the rate of divergence and/or agreement between subjective and objective methods of polyp size estimation, the agreement between surveillance intervals based on optical diagnosis by CAD-eye and pathological findings, and the false positive rate and latency for polyp detection.

Eligibility Criteria:
Inclusion Criteria:

* indication of undergoing a screening, surveillance, or diagnostic colonoscopy
* Age 45-80 years
* Signed informed consent

Exclusion Criteria:

* Known inflammatory bowel disease (IBD)
* Active Colitis
* Poor general health, defined as an American Society of Anesthesiologists (ASA) physical status class \>3
* Coagulopathy
* Familial polyposis syndrome
* Emergency colonoscopies
* Poor bowel preparation score defined as the total Boston bowel preparation score \<6 and the right-segment score \<2.

For per-polyp analysis:

1. For optical diagnosis (CADx) we will exclude all polyps \>5mm. We will also exclude sessile serrated polyps and traditional serrated adenomas from the analysis as CADx can only differentiate between adenomas and hyperplastic polyps.
2. For polyp size measurement (SCALE-EYE), we will exclude all polyps resected in several pieces (piecemeal resection), or specimens damaged (e.g., fractured) during the suction and retrieval process, submillimeter polyps too small for measurement after resection. Polyps after the 5th resected polyp in a single piece will be excluded to reduce the time associated with the procedure.
3. For polyp detection (CADe) we will not exclude any polyp from the analysis.