T2-weighted MRI of rectosigmoid carcinoma: comparison of respiratory-triggered fast spin-echo, breathhold fast-recovery fast spin-echo, and breathhold single-shot fast spin-echo sequences.

摘要

PURPOSE: To compare the abilities of T2-weighted (T2W) imaging using respiratory-triggered fast spin-echo (RT-FSE), breathhold fast-recovery FSE (BH-FRFSE), and BH single-shot FSE (BH-SSFSE) sequences without an endorectal coil to detect rectosigmoid carcinomas. MATERIALS AND METHODS: Forty patients (stage: pT0, 1; pTis-2, 15; pT3-4, 24) were included in the study. All examinations were performed on a 1.5T magnet with a phased-array coil and the patients were studied in the prone position with per-anal air injection. Qualitative and quantitative evaluations were performed. RESULTS: Motion artifact was the most prominent with the RT-FSE sequence, and the least prominent with the BH-SSFSE sequence. Scores for depiction of the rectal wall layer, tumor recognition, and overall image quality were the highest with the BH-FRFSE sequence. On the basis of a receiver operating characteristic (ROC) analysis, the detection rate of tumor invasion through the rectal wall was higher with the BH-FRFSE sequence (Az = 0.9077) than with the RT-FSE (Az = 0.7762, p < 0.05) or BH-SSFSE (Az = 0.8602) sequence. Tumor-to-fat contrast was highest with the BH-FRFSE sequence (P < 0.017). CONCLUSION: The BH-FRFSE sequence may be the first choice for rectosigmoid T2W imaging in the prone position with per-anal air injection for patients who can hold their breath stably.