title: Role of virtual computed tomographic colonography in patients with colorectal cancers and obstructing colorectal lesions.
abstract: OBJECTIVE
  The aim of this study was to assess the ability of computed tomographic colonography to diagnose colorectal masses, stage colorectal cancers, image the proximal colon in obstructing colorectal lesions, and evaluate the anastomoses in patients with previous colorectal surgery.
  
  
  METHODS
  We prospectively performed computed tomographic colonography examinations in 34 patients (20 males; mean age, 64.2; range, 19-91 years): 20 patients had colorectal masses (defined at endoscopy as intraluminal masses 2 cm or larger), 7 patients had benign obstructing colorectal strictures, and 7 patients had a prior colorectal resection. Final tumor staging was available in all 16 patients who had colorectal cancers and 15 patients were referred after incomplete colonoscopy. The ability of computed tomographic colonography to stage colorectal cancers, identify synchronous lesions in patients with colorectal masses, and image the proximal colon in patients with obstructing colorectal lesions was assessed.
  
  
  RESULTS
  Computed tomographic colonography identified all colorectal masses, but overcalled two masses in patients who were either poorly distended or poorly prepared. Computed tomographic colonography correctly staged 13 of 16 colorectal cancers (81 percent) and detected 16 of 17 (93 percent) synchronous polyps. Computed tomographic colonography over-staged two Dukes Stage A cancers and understaged one Dukes Stage C cancer. A total of 97 percent (87/90) of all colonic segments were adequately visualized at computed tomographic colonography in patients with obstructing colorectal lesions compared with 60 percent (26/42) of segments at barium enema (P < 0.01). Colonic anastomoses were visualized in all nine patients, but in one patient, computed tomographic colonography could not distinguish between local tumor recurrence and surgical changes.
  
  
  CONCLUSIONS
  Computed tomographic colonography can accurately identify all colorectal masses but may overcall stool as masses in poorly distended or poorly prepared colons. Computed tomographic colonography has an overall staging accuracy of 81 percent for colorectal cancer and is superior to barium enema in visualizing colonic segments proximal to obstructing colorectal lesions.
authors.affiliation: Department of Radiology, and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Morrin
authors.forename: R J
authors.initials: RJ
authors.lastname: Farrell
authors.forename: V
authors.initials: V
authors.lastname: Raptopoulos
authors.forename: J B
authors.initials: JB
authors.lastname: McGee
authors.forename: R
authors.initials: R
authors.lastname: Bleday
authors.forename: J B
authors.initials: JB
authors.lastname: Kruskal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000714:Anastomosis, Surgical; D003108:Colonic Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D003111:Colonic Polyps / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007415:Intestinal Obstruction / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012002:Rectal Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface