Preoperative staging of rectal carcinoma using double-contrast MR imaging. Technical aspects and early clinical experiences.
OBJECTIVE
To improve preoperative staging of rectal carcinoma with MR imaging, using a double-contrast technique.


METHODS
Imaging was performed in 12 patients before and after i.v. injection of Gd-DTPA and rectal administration of a superparamagnetic contrast medium, mainly containing magnetite. The diagnostic information was evaluated and compared with findings at surgery and histopathological analysis.


RESULTS
The superparamagnetic contrast medium enema caused a distension of the rectum and intraluminal signal void, whereas Gd-DTPA enhanced the mucosa in T1-weighted images. This allowed an evaluation of the normal rectal wall and separation of the mucosa, tunica muscularis and perirectal space in all cases, which was not possible in T1- or T2-weighted precontrast images. The rectal carcinoma could be delineated and tumor invasion to the rectal wall determined in all cases. The findings in postcontrast MR corresponded with the findings at histopathological examination in 11 of 12 patients. The histopathological examination in one patient revealed metastases (< 1 cm) in regional lymph nodes, too small to be identified in pre- or postcontrast MR images.


CONCLUSIONS
Double-contrast-enhanced MR imaging allows evaluation of the normal rectal wall and preoperative staging of rectal carcinoma.
Department of Diagnostic Radiology, University Hospital, Lund, Sweden.
N O
NO
Wallengren
S
S
Holtås
A
A
Andrén-Sandberg
D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000473:pathology*; D003287:Contrast Media; D004733:Enema; D005260:Female; D005290:Ferric Compounds; D019786:Gadolinium DTPA; D006801:Humans; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000473:pathology*; D012007:Rectum / Q000473:pathology*
D003287:Contrast Media; D005290:Ferric Compounds; D009942:Organometallic Compounds; C101499:ferristene; D004369:Pentetic Acid; D019786:Gadolinium DTPA