Preoperative locoregional staging of rectal carcinoma: comparison of MR, TRUS and Multislice CT. Personal experience.

The aim of this study was to measure the sensitivity and clinical indications of Magnetic Resonance (MR) as compared to Transrectal Ultrasonography (TRUS) and spiral Computed Tomography (CT) in the preoperative staging and evaluation of rectal carcinoma. Twenty patients with histologically proven rectal carcinoma were examined with phased-array coil MRI. We used T1 and T2, spin-echo, turbo-spin-echo, flash2D sequences with and without fat suppression; FOV 180-280; 4-6 mm slice thickness; i.v. Gadolinium. The MR images were compared with TRUS, spiral CT and with the final histological diagnosis. MR showed a 92.3% sensitivity for rectal wall infiltration vs. 100% of TRUS and 75% of CT. The sensitivity for lymph node metastases was 76.4% vs. 72.2% for TRUS and 88% for CT. Locoregional staging of rectal cancer by MRI shows a high sensitivity and is also feasible in stenosing or proximal rectal lesions. TRUS, despite its limitations, is still the most sensitive method for the evaluation of wall infiltration. CT was less sensitive than the other two The sensitivity of MR and CT for lymph node metastases is comparable, but the former is more specific.