CT vs MRI in diagnosis of recurrent rectosigmoid carcinoma.
OBJECTIVE
Our goal was to compare the relative values of MRI vs. CT in diagnosing recurrent rectosigmoid cancer.


METHODS
We conducted a retrospective review of 18 patients who had surgical resection of primary rectosigmoid carcinoma and suspected recurrence. They were studied with CT and MR and followed for up to 4 years.


RESULTS
At the time of the initial imaging, 10 patients had recurrent tumor and 4 of the remaining 8 patients later demonstrated local recurrence. Magnetic resonance demonstrated 91% sensitivity, 100% specificity, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 89% with a 95% accuracy. Computed tomography demonstrated a sensitivity of 82% and a specificity of 50% with a PPV of 69% and an NPV of 67% with an accuracy of 68%. In three cases interpreted on CT as presacral masses, all were shown on MR to represent displaced but normal pelvic structures. In four cases MR revealed tumor involving the sacrum and sacral nerves not apparent on CT.


CONCLUSIONS
Magnetic resonance showed superior sensitivity, specificity, and accuracy to CT and better definition of the extent of tumor.
Pema
P J
PJ
Department of Radiology, Ohio State University Medical Center, Columbus.
Bennett
W F
WF
Bova
J G
JG
Warman
P
P
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D012809:Colon, Sigmoid / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000601:surgery; D012007:Rectum / Q000473:pathology; D012680:Sensitivity and Specificity; D012811:Sigmoid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000601:surgery; D015996:Survival Rate; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000379:methods
D003287:Contrast Media