Preoperative staging of rectal tumors: comparison of endorectal ultrasound, hydro-CT, and high-resolution endorectal MRI.
OBJECTIVE
The aim of this study was to compare transrectal ultra-sound (TRUS), hydro-computed tomography (hydro-CT), and endorectal magnetic resonance imaging (MRI) in the preoperative staging of rectal cancer.


METHODS
23 patients with rectal adenocarcinoma underwent TRUS, hydro-CT, and MRI (1 Tesla) with endorectal coil. The results were correlated with the histopathological findings based on the TNM classification.


RESULTS
T staging with TRUS, hydro-CT, and endorectal MRI correlated with the histopa-thological findings in 83% of patients (19/23). Tumors were overestimated by TRUS in 2/23 patients, by CT in 3/23, and by MRI in 3/23 patients. Tumor size was underestimated by TRUS in 2 patients, by CT and MRI in 1 case each. Local lymphatic node involvement was correctly diagnosed with CT and MRI in 87% and 83%, respectively. Using TRUS, false-negative results in the staging of lymph node involvement were seen in 3/23 patients, whereas 1 patient was over-staged. Using hydro-CT as well as endorectal MRI, overstaging of the local lymph nodes took place in 2/23 patients.


CONCLUSIONS
All methods are limited because peritumoral inflammation cannot be precisely distinguished from infiltration by the tumor. Correct lymph node staging is hampered in advanced disease using TRUS. In these patients, further cross-sectional imaging may be required.
Dinter
Dietmar J
DJ
Institut für Klinische Radiologie und Nuklearmedizin, Universitätsklinikum Mannheim, Mannheim, Germany. dietmar.dinter@rad.ma.uni-heidelberg.de
Hofheinz
Ralf-Dieter
RD
Hartel
Mark
M
Kaehler
Georg F A B
GF
Neff
Wolfgang
W
Diehl
Steffen J
SJ
D000230:Adenocarcinoma / Q000145:classification / Q000175:diagnosis* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011300:Preoperative Care / Q000379:methods; D012004:Rectal Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000601:surgery; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*