Double-contrast MR colonography: in vivo experimental study in an animal model.
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.
Boraschi
Piero
P
2nd Department of Radiology, Pisa University Hospital, Pisa, Italy. p.boraschi@do.med.unipi.it
Neri
Emanuele
E
Vannucci
Luca
L
Vagli
Paola
P
Braccini
Giovanni
G
Bartolozzi
Carlo
C
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
D003287:Contrast Media