Dynamic Contrasted MR Imaging in Differentiation of Recurrent Malignant Soft Tissue Tumor from Posttreatment Changes
Suphaneewan Jaovisidha MD*, Punjamas Traiporndeeprasert MD*, Niyata Chitrapazt MD*, Ammarin Thakkinstian PhD**, Adisak Nartthanarung MD***, Thanya Subhadrabandhu MD***, Pimjai Siriwongpairat MD*
Affiliation : * Department of Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ** Section of Clinical Epidemiology and Biostatistics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand *** Department of Orthopedics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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 and five 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 post-
treatment 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.
Keywords : Magnetic resonance (MR), Dynamic, Dynamic contrasted, Malignant, Soft tissue tumor, Recurrent
