Performance of radiographic imaging after incomplete colonoscopy for nonmalignant causes in clinical practice

Background and Aims: CT colonography (CTC) or barium enema are commonly ordered to complete colorectal imaging after an incomplete colonoscopy. We evaluated the sensitivity of radiographic studies performed for this purpose in clinical practice outside clinical trials. Methods: Adult patients referred to an expert endoscopist for incomplete colonoscopy because of a redundant colon or a difficult sigmoid and who underwent previous radiographic imaging between July 2001 and July 2019 were identified. None of the patients had a malignant obstruction as the cause of incomplete colonoscopy. Data on polyp size, location, and pathology were obtained from colonoscopy and radiology reports. Polyps identified on imaging and colonoscopy were matched based on polyp size and location. Results: Among 769 patients referred for incomplete colonoscopy, we identified 65 with a radiographic examination performed within 36 months of colonoscopy at our center. Per-patient sensitivity for CTC was suboptimal (70%) and was very low for barium enema (26.7%). Per-polyp sensitivity for both CTC and barium enema was poor (23.8% and 7.6%). Quality of the examination did not seem to affect procedure sensitivity. Conclusions: Radiographic imaging after incomplete colonoscopy for reasons other than malignant obstruction had poor sensitivity for polyps. Patients with incomplete colonoscopies should be considered for repeat colonoscopy by an expert.