title: Virtual CT colonoscopy versus conventional colonoscopy: a prospective study.
abstract: OBJECTIVE
  Diagnosis of colorectal diseases might be a challenge. This prospective study aimed to evaluate virtual CT colonoscopy (CT colonography) as a new diagnostic modality in colorectal diseases.
  
  
  METHODS
  Thirty-two patients (22 males and 10 females, mean age 47 years) with different colorectal complaints were investigated by CT colonography. Scanning parameters were collimation of 5mm, table speed of 6.25mm/s and pitch of 1.25. All images were evaluated in axial slices, reformatted images with endoluminal and extraluminal views. All patients were re-examined by the conventional colonoscope. The CT colonography and the colonoscopy findings were correlated.
  
  
  RESULTS
  CT colonography suspected colorectal malignancy in 14 patients, diagnosed colorectal polyps in 4 (out of 6), suspected inflammatory bowel diseases in 5 (out of 6), showed colonic diverticulae in 3 (out of 4), and found no abnormality in 2 patients. CT colonography displayed the proximal colon above the obstructing lesion in extraluminal views, fungating mass in endoluminal view and accurately localized the lesion. In inflammatory bowel diseases, segmental (in 4 patients) or skipped (one patient) wall thickening, loss of colonic haustration (3 patients) and pseudopolyps (one patient) were detected. Superficial ulcers were missed. Endoluminal images displayed the orifices of the diverticulae in 3 patients. The CT colonography sensitivity was 86.7% and its specificity was 100%.
  
  
  CONCLUSIONS
  The high resolution and multiple image display of CT colonography allow detection of many colorectal lesions. CT colonography is also a noninvasive imaging modality that is particularly valuable in poor risk patients and for colorectal examination proximal to an obstructing lesion.
authors.affiliation: Department of Diagnostic Radiology, Mansoura Faculty of Medicine, Mansoura University, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Abdel Razek
authors.forename: Mostafa M
authors.initials: MM
authors.lastname: Abu Zeid
authors.forename: Maha
authors.initials: M
authors.lastname: Bilal
authors.forename: Nermeen M
authors.initials: NM
authors.lastname: Abdel Wahab
mesh_terms: D000328:Adult; D000368:Aged; D003082:Colectomy / Q000379:methods; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*