RESUMO
OBJECTIVE: To investigate dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in term of differentiation recurrent malignant soft tissue tumor (MSTT) from post-treatment changes. MATERIAL AND METHOD: DCE-MRI was performed in consecutive patients in two-year periods to differentiate recurrent MSTT from post-treatment (surgery radiotherapy chemotherapy) changes. The steepest slope (SS) ratio between the artery and the lesion, sensitivity, and specificity were calculated. RESULTS: Thirty-five DCE-MRI studies were performed in 30 patients, which included 14 males and 16 females with an age range from 12 to 71 years (median 45.81 year). Thirteen were with recurrence and 22 were with post-treatment changes. The SS ratios were ranged from 0.66 to 29.15. The lesions with the SS ratio > 9.28 were all benign at follow up of at least two months, whereas those with SS ratio < 1.05 were all recurrent tumors proven by biopsy or surgery. Overlapping occurred when the SS ratios > 1.05 but < 9.28 in which the recurrence was 42.31%. The chance of having recurrence rather than post-treatment changes was approximately two andfive times in patients with the ratio of 5. 07 and 1.55, with the specificity of 54.55% and 90.91%, respectively CONCLUSION: The SS ratio between the artery and the lesion has limitations to differentiate recurrent MSTT from posttreatment changes. It is useful when the ratio is less than 1.05 (malignant) or more than 9.28 (benign). The chance of having recurrence rather than post-treatment changes was approximately two and five times in patients with the ratio of 5.07 and 1.55, respectively The less value the ratio is, the more possibility to be recurrent tumor.