The clinical value of DCE-MRI Semi-quantitative parameters in monitoring neoadjuvant chemotherapy response of osteosarcoma

Abstract

Objective To evaluate the response of neoadjuvant chemotherapy on osteosarcoma by semi-quantitative parameters of dynamic contrast-enhancement magnetic resonance imaging (DCE-MRI). Methods Retrospectively analysis 25 cases of osteosarcoma confirmed by pathology.All cases received DCE-MRI scan before and after 4 cycles of neoadjuvant chemotherapy.The following semi-quantitative parameters were calculated by post-processing software: early dynamic enhancement wash-in slope (Slope), maximum signal intensity (SImax), time to peak (TTP), signal enhanced extent (SEE), peak percent enhancement (PPE), wash out rate (WOR), enhancement rate (R). All cases were divided into good response group (tumor necrosis rate ≥90%, n=12) and non-response group (tumor necrosis rate <90%, n=13) according to the Huvos grading method. Semi-quantitative parameters of DCE-MRI before and after neoadjuvant chemotherapy between good response group and non-response group were compared by Mann-whitney U test. Receiver operating characteristic curve (ROC) analysis was performed to evaluate the efficacy of different good response group and non-response group after neoadjuvant chemotherapy (NAC). Results Slope, SImax, TTP, SEE, PPE, WOR, R, TTP, WOR before and after NAC in good response group were significant different (P<0. 05), but only SImax, SEE in non-response group. TTP, R were significant different between the above two groups before NAC, and Slope, SImax, TTP, SEE, WOR, R were significant different after NAC (P<0.05). ROC was used to predict the diagnostic efficiency of various parameters for tumor necrosis rate after osteosarcoma NAC. It was found that the sensitivity and specificity of Slope, TTP and R parameters for predicting the response of osteosarcoma after chemotherapy were 83.3% and 92.3%, 91.7% and 69.2%, 84.6% and 75.0% respectively. The area under the curve (AUC) were 0.872 (95% CI: 0.716 to 1.027), 0.846 (95% CI: 0.685 to 1.007), 0.833 (95% CI: 0.662 to 1.004), the cut-off value were 0.032, 175 s, 5.441, Youden index were 0.756, 0.609, 0.596, respectively. Conclusions Slope, TTP, R were the most valuable semi-quantitative parameter of DCE-MRI to predict the response of NAC in osteosarcoma. Key words: Osteosarcoma; Neovascularization, pathologic; Magnetic resonance imaging; Magnetic resonance angiography