Colorectal neoplasm detection using virtual colonoscopy: a feasibility study

摘要

Background—Virtual colonoscopy is a potentiallypowerful tool for non-invasive colorectal evaluation. In vitro studieshave established its accuracy in simulated polyp detection but little data exist regarding its use in clinical practice. 
Aims—To evaluate the ability of virtualcolonoscopy to detect colorectal cancers and polyps in patients withendoscopically proven colorectal neoplasms and to correlate thefindings of virtual colonoscopy with those of conventional colonoscopy,surgery, and histopathology. 
Patients—Thirty eight patients with endoscopicfindings suggestive of colorectal carcinoma. 
Methods—Virtual colonoscopy was performed usingthin section helical computed tomography (CT) of the abdomen and pelvisafter rectal insufflation of room air. Commercially available software was used to generate endoscopic "fly through" examinations of thecolon from the CT data. Results were correlated with the findings ofconventional colonoscopy and with the surgical and histopathological outcome in each case. 
Results—Thirty eight pathologically provencolorectal cancers and 23 adenomatous polyps were present. On virtualcolonoscopy, all cancers and all polyps measuring greater than 6 mm insize were identified; there were two false positive reports of polyps. On conventional colonoscopy, there was one false positive report of amalignant sigmoid stricture; four subcentimetre polyps were overlooked.Virtual colonoscopy enabled visualisation of the entire colon in 35 patients; conventional colonoscopy was incomplete in 14 patients.Virtual colonoscopy correctly localised all 38cancers, compared with32 using conventional colonoscopy. 
Conclusion—Virtual colonoscopy is a feasiblemethod for evaluating the colon; it may have role in diagnosis ofcolorectal cancer and polyps.