DYNAMIC CONTRAST-ENHANCED SUBTRACTION VERSUS T2-WEIGHTED SPIN-ECHO MR-IMAGING IN THE FOLLOW-UP OF COLORECTAL NEOPLASM - A PROSPECTIVE-STUDYOF 41 PATIENTS

PURPOSE: To compare dynamic contrast-enhanced subtraction (DCES) and T 2-weighted spin-echo (SE) magnetic resonance (MR) imaging in the diffe rentiation of fibrosis from recurrence during the follow-up of treated colorectal neoplasms. MATERIALS AND METHODS: Forty-one patients with 39 malignant and 16 benign lesions confirmed by means of surgery (n = 23), biopsy (n = 24), or 12-month follow-up examination (n = 8) underw ent DCES MR imaging and Ta-weighted SE MR imaging. Enhancement of an a bnormal pelvic structure within the first 90 seconds on DCES images or high signal intensity on T2-weighted SE images was considered indicat ive of malignancy. RESULTS: Sensitivity, specificity, and positive and negative predictive values were, respectively, 97%, 81%, 93%, and 100 % for DCES MR imaging and 77%, 56%, 81%, and 56% for T2-weighted MR im aging. The number of correctly classified lesions was significantly hi gher with DCES imaging compared with T2-weighted imaging (P less than or equal to .006). CONCLUSION: DCES imaging is more accurate than T2-w eighted SE imaging for differentiating fibrosis from recurrence during the follow-up of treated colorectal neoplasms.