ASSESSMENT OF RECTAL TUMOR INFILTRATION UTILIZING ENDORECTAL MR-IMAGING AND COMPARISON WITH ENDOSCOPIC RECTAL SONOGRAPHY

Background: The preoperative assessment of depth of invasion of rectal carcinoma is increasingly important as new treatment methodologies ar e developed. Accuracy of preoperative endorectal MR imaging was theref ore compared with that of the endoscopic rectal sonography in determin ing depth of invasion of rectal carcinomas. Method: From March 1993 to April 1994, 10 consecutive patients with biopsy-proven rectal carcino mas were imaged with both endorectal MR imaging and endoscopic rectal sonography. These two studies were performed an average of 2.7 days ap art in each patient. All 10 patients had surgical resection of the rec tal carcinoma within days of imaging studies. TNM staging of each mali gnant lesion was correlated with the imaging reports. Result: Staging accuracy was 80% for endorectal MR imaging and 70% for endoscopic rect al sonography. With MR imaging, one T2 lesion was overstaged and one T 3 lesion was understaged. With sonography, two T2 lesions were oversta ged and one T3 lesion was understaged. One MR error resulted from misi nterpretation. All other staging errors occurred in patients with tumo r spread into, but not through, the muscularis propria or with microsc opic spread through this layer. Conclusions: Endorectal MR imaging and endoscopic rectal sonography have similar accuracy for assessing dept h of invasion of rectal carcinoma. (C) 1997 Wiley-Liss, Inc.