The role of dynamic contrast-enhanced MRI in differentiation of local recurrence and residual soft-tissue tumor versus post-treatment changes

Abstract

To evaluate the reliability of dynamic contrast-enhanced MRI in the diagnosis of local recurrence of malignant soft-tissue tumors after receiving treatment. From March 2002 till December 2009 we performed dynamic contrast enhanced MRI in 95 patients with soft-tissue tumor after receiving treatment (surgery, radiotherapy, chemotherapy). Patients were classified according to five types of TIC. The recurrent disease was suspected in 47 patients and the biopsy was recommended. In 8 cases (TIC II), the biopsy was performed due to long-term post-treatment changes. Histological results proved STT recurrence in 45 patients; in 10 patients (8 with TIC II), biopsy revealed hypervascular granulation tissue, florid inflammation and reactive changes. The sensitivity for dynamic contrast-enhanced MR examination was 100 %, specificity 80 %, positive predictive value (PPV) 95.7 % and negative predictive value (NPV) 100 %. Our results indicate that TICs III, IV and V raise high suspicion of local tumor recurrence and require percutaneous imaging-guided biopsy. TIC of type II usually represents a pseudomass and the biopsy should be performed only in selected cases with increased risk of recurrent disease based on multidisciplinary approach. On the basis of literature review as well as our experiences we created a reliable algorithm proposed for diagnosing the residual or recurrent soft-tissue tumors (Tab. 2, Fig. 6, Ref. 20).