ACCURACY OF STAGING RECTAL TUMORS WITH CONTRAST-ENHANCED TRANSRECTAL MR-IMAGING

OBJECTIVE. Our objective was to evaluate the accuracy of contrast-enha nced transrectal MR imaging in staging rectal adenoma and carcinoma by correlating with histopathologic findings, SUBJECTS AND METHODS, Thir ty-five patients underwent transrectal MR imaging on a 1.5-T supercond ucting unit using unenhanced T1-weighted and T2-weighted spin-echo and turbo spin-echo sequences, a dynamic gadopentetate dimeglumine-enhanc ed turbo fast low-angle shot sequence, and enhanced T1-weighted spin-e cho sequences, For all patients, histopathologic correlation was avail able from biopsy (ii = 15) or surgical resection (it = 20), Two radiol ogists unaware of each other's interpretations of the scans interprete d each case from which we evaluated qualitative and quantitative data, RESULTS, Rectal adenomas (ii = 15) were identified when imaging revea led an intact muscularis mucosae, a homogeneous internal structure, an d high contrast enhancement of the lesion. Carcinomas staged as T1 by TNM criteria (it = 6) were best revealed by dynamic turbo fast low-ang le shot sequences, in which an intact muscularis propria could be seen , Visualization of enhancing tumor tissue in the muscularis propria. i ndicated T2 carcinoma (it = 5), AU T3 (n = 5) and T4 (it = 4) carcinom as were correctly staged with dynamic and static MR imaging, The stage revealed by MR imaging correlated well with histologic staging result s in 89% (observer 1) and 86% (observer 2) of interpretations, However , when interpreting MR imaging, observers tended to overstage and neve r understaged, CONCLUSION, Transrectal surface-coil MR imaging provide d reliable information in staging patients before surgery and in evalu ating rectal adenoma and carcinoma.