Osteosarcoma and Ewing's sarcoma after neoadjuvant chemotherapy: value of dynamic MR imaging in detecting viable tumor before surgery.

Abstract

Fast dynamic contrast-enhanced sequences are essential for identifying residual tumor before surgery. A short time interval of less than 6 sec between arterial enhancement and tumoral enhancement strongly correlates with presence of viable tumor. Both therapy-related alterations of tissue and tumor-related matrices must be considered when late or lack of enhancement is noted on dynamic MR images.