MR-IMAGING IN THE FOLLOW-UP OF MALIGNANT AND AGGRESSIVE SOFT-TISSUE TUMORS - RESULTS OF 511 EXAMINATIONS

PURPOSE: To present magnetic resonance (MR) imaging findings from 511 follow-up examinations of aggressive soft-tissue tumors. MATERIALS AND METHODS: One hundred eighty-two patients with aggressive soft-tissue tumors underwent postoperative T1- and T2-weighted imaging; 41 also un derwent 51 gadolinium-enhanced T1-weighted examinations, and five unde rwent dynamic gadolinium-enhanced sub-traction imaging. RESULTS: Twent y-four of 25 patients (101 of 102 examinations) without high signal in tensity (HSI) at T2-weighted imaging had no recurrence. Among 79 patie nts (321 examinations) who demonstrated HSI without a mass, only two t umors recurred within 1 year. An HSI mass was found in 88 studies of 7 8 patients and represented recurrence (n = 60), hygroma (n = 24), or a radiation-induced pseudomass (n = 4). Hygromas did not enhance, while recurrences enhanced at 1-3 minutes and postirradiation change enhanc ed at 4-7 minutes. CONCLUSION: T2-weighted imaging can be used to iden tify possible recurrence of aggressive soft-tissue tumors, while gadol inium-enhanced imaging can be used to differentiate recurrences from h ygromas and inflammatory change.