Local staging of rectal cancer: assessment with double-contrast multislice computed tomography and transrectal ultrasound.

Abstract

The aim of this study was to evaluate the accuracy of multislice computed tomography (MSCT) with double-contrast technique and transrectal ultrasound (TRUS) in staging of rectal carcinoma compared with histopathological confirmation. In a prospective study of 92 patients with rectal carcinoma, preoperative MSCT with negative rectal contrast (methylcellulose) and intravenous contrast was performed. Reconstructions in 3 planes were analyzed in a cine mode in picture archiving and communication (PAC) system. Analysis of rectal wall infiltration was performed preoperatively according to a modified tumor, nodes, metastases (TNM)-classification system (< or =T2/T3/T4, N0/N+, UICC/UICC I > I). MSCT imaging findings were compared with the results of TRUS and histopathology in all patients. With interactive multiplanar image viewing, the results of MSCT of depth of rectal wall invasion (T-staging) were as follows: sensitivity, specificity, positive and negative predictive values, and accuracy rate were 85%, 87%, 88%, 84%, and 86% (54/63 patients) compared with 59%, 63%, 72%, 48%, and 60% (38/63 patients), respectively, for TRUS staging in the same patients. The sensitivity, specificity, positive and negative predictive values, and accuracy rate of MSCT for perirectal nodes evaluation was 75%, 85%, 75%, 85%, and 81% (51/63 patients) compared with 55%, 71%, 50%, 74%, and 65% (41/63 patients), respectively, for TRUS in detecting metastatic lymph nodes. Preoperative double-contrast MSCT accurately indicates the exact depth of tumor infiltration and improves lymph node staging. The new technical innovations of MSCT provide superior information for preoperative staging of rectal cancer and may compete with TRUS as the standard preoperative diagnostic method.