title: Double-contrast MR colonography: in vivo experimental study in an animal model.
abstract: BACKGROUND
  We evaluated the performance of double-contrast MR colonography in detecting colorectal tumors experimentally induced by chemical substances in the large bowel of the rat.
  
  
  METHODS
  Eight Sprague-Dawley rats developed 67 chemically induced tumors of the large bowel. The animals were imaged with a double-contrast MR technique at 0.5T, using a head coil for both signal transmission and reception. Prior to MR acquisition, room air was insufflated into the rats' large bowel. Unenhanced and contrast-enhanced T1, proton-density and T2 sequences were obtained in the axial and coronal planes. Autopsy was performed immediately after MR examination. MR images were interpreted by consensus of two observers, and the results were compared with post-mortem data.
  
  
  RESULTS
  Sensitivity (60% vs. 93%), specificity (63% vs. 81%), positive (85% vs. 93%) and negative (30% vs. 81%) predictability, and global diagnostic accuracy (60% vs. 89%) were obtained for all tumors (n=67) and for the group of tumors larger than 1.5 cm (n=43), respectively. No tumors less than 1.5 cm were detected.
  
  
  CONCLUSIONS
  Double-contrast MR colonography is a promising modality in detecting colorectal neoplasms larger than 1.5 cm in an animal tumor model.
authors.affiliation: 2nd Department of Radiology, Pisa University Hospital, Pisa, Italy. p.boraschi@do.med.unipi.it
authors.forename: Piero
authors.initials: P
authors.lastname: Boraschi
authors.forename: Emanuele
authors.initials: E
authors.lastname: Neri
authors.forename: Luca
authors.initials: L
authors.lastname: Vannucci
authors.forename: Paola
authors.initials: P
authors.lastname: Vagli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Braccini
authors.forename: Carlo
authors.initials: C
authors.lastname: Bartolozzi
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D003287:Contrast Media / Q000494:pharmacology; D004195:Disease Models, Animal; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003287:Contrast Media