[Staging of rectal cancer: assessment with Gd-DTPA enhanced MR imaging]

This study was designed to assess the value of Gd-DTPA enhanced imaging in the staging of rectal carcinoma. Twenty-five patients were prospectively evaluated with MR imaging using a 1.5 Tesla unit. Based on the results of a barium study and/or digital examination, a balloon catheter was inserted to the level of the lesion before examination. Both T1- and T2-weighted images and Gd-DTPA enhanced images were obtained in all patients, and Gd-DTPA enhanced fat-saturation images were obtained in 11 patients. When both T1- and T2-weighted images were used, 24% of tumors were ill defined. However, when Gd-DTPA and Gd-DTPA enhanced fat-saturation imaging was added, all tumors were well defined and the quality of the images increased. There was no significant difference between images in the detection of muscular invasion. In the detection of perirectal fat invasion, however Gd-DTPA fat-saturation imaging showed increased sensitivity. Nevertheless, it also decreased specificity, so there was no significant difference between images. In the detection of metastatic lymph nodes, Gd-DTPA enhanced and Gd-DTPA enhanced fat-saturation imaging were not useful. Tumor detection using Gd-DTPA enhanced fat-saturation images was excellent. However, the accuracy of staging was not improved by supplemental Gd-DTPA enhancement.