RT Journal Article SR Electronic T1 Computed tomography colonography (virtual colonoscopy): a new method for colorectal screening JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 301 OP 305 DO 10.1136/gut.44.3.301 VO 44 IS 3 A1 C D JOHNSON A1 D A AHLQUIST YR 1999 UL http://gut.bmj.com/content/44/3/301.abstract AB