FULL PAPER Multiparametric MRI with diffusion- weighted imaging in predicting response to chemotherapy in cases of osteosarcoma and Ewing’s sarcoma

Objective: To evaluate the multiparametric MRI in predicting chemotherapy response in pathologically proven cases of osteosarcoma and Ewing’s sarcoma. Correlation between the tumor size changes and internal breakdown using RECIST 1.1, modified RECIST, quantitative apparent diffusion coefficient (ADC) and tumor volume as well as dynamic contrast- enhanced MRI (DCE- MRI). The study included 104 patients pathologically proved osteosarcoma (53) and Ewing`s sarcoma (51) underwent MRI examinations; before and after chemotherapy. All patients were assessed using the RECIST 1.1 criteria, m- RECIST, quantitative ADC, and tumor volume evaluation. 21 patients underwent DCE- MRI curve type with quantitative parameters. Correlation between the different evaluations was carried out. Results were correlated with the post- operative pathology in 42 patients who underwent surgery and for statistical evaluation, Those patients were classified into responders ( ≥ 90% necrosis) and non- responders (<90% necrosis). Results: The initial mean ADC of 104 patients of osteosarcoma and Ewing’s sarcoma (0.90 ± 0.29) and (0.71 ± 0.16) respectively, differed significantly from that after treatment (1.62 ± 0.46) and (1.6 ± 0.39) respectively with ( p <0.001).