OBJECTIVESTo study the usefulness of CT virtual colonoscopy (CTVC) in patients with incomplete conventional colonoscopy (CC) and assess the statistical differences between two methods of colorectal segment examination.

METHODSSixty patients with incomplete CC underwent volume scanning using spiral CT. CT VC images were obtained using a navigator software in workstation. All patients were confirmed by surgical or CC biopsy histology. Statistical analysis was done using t test comparing two sample percentages.

RESULTSCTVC succeeded in 55/60 patients (91.7%) who had incomplete CC. Additional lesions were identified in the proximal colon in 15/55 patients (27.3%), including 1 primary carcinoma, 16 polyps in 13 patients and 1 ulcerative colonitis. The main cause of incomplete CC was occlusive mass; others were redundant, tortuous colon loops, and excessive colonic spasm. There was a statistically significant difference between the two methods in colorectal segment examination.

CONCLUSIONCTVC is a feasible and effective adjunctive method for evaluating the entire colorectal segment following an incomplete CC procedure. It offers a new approach for colorectal examination.