Response Monitoring to Neoadjuvant Chemotherapy in Osteosarcoma Using Dynamic Contrast-Enhanced MR Imaging

To evaluate the dynamic contrast-enhanced MRI parameters for monitoring the neoadjuvant chemotherapy (NAC) response in osteosarcoma prospectively. A total of 19 patients with osteosarcoma were recruited and underwent two dynamic contrast-enhanced MRI (DCE-MRI) examinations before and after chemotherapy. Patients with ≥ 90% tumor necrosis were defined as responders (10 patients), and those < 90% necrosis were defined as non-responders (9 patients). Primary tumor kinetic parameters of DCE were measured including Ktrans, Kep, Ve, and Vp with the extended Tofts model. The change in tumor volume was also recorded in the treatment cycle. The changes between responders and non-responders were compared using t test or Mann–Whitney U test. The ROC curves were used to evaluate the ability of DCE parameters for differentiating the responders and non-responders with respect to chemotherapy. Statistically significant differences were not detected in Ktrans, Kep, Vp, Ve, and MRV between responder and non-responder groups before chemotherapy. The Ktrans and Kep showed significant differences between responder and non-responder groups after completion of NAC (P < 0.05). Compared to the non-responders, the Ktrans and Kep were significantly lower in the responders than non-responders after completion of NAC (P < 0.05). The sensitivity, specificity, and diagnostic accuracy of Ktrans (Ktrans-post) and Kep (Kep-post) were distinguished between the non-responder and responder groups. Ktrans (Ktrans-post) and Kep (Kep-post) were analyzed together to differentiate between responders and non-responders that revealed the largest AUCs. The current study showed that the DCE parameters could adequately monitor the response to NAC in the osteosarcoma treatment cycle.