Dynamic Contrast-Enhanced MR Imaging in Musculoskeletal Tumors

Radiologists are required to provide information on four clinical questions in imaging primary musculoskeletal neoplasms: diagnosis, staging, response to pre-surgical (or initial) chemotherapy1, and detection of recurrence. MRI is useful, together with radiography and clinical data, in narrowing the differential diagnosis and establishing the extent of disease. However, it rarely provides a defi nitive diagnosis for these tumors. MRI is the pre-eminent imaging modality for the remaining three clinical questions (Bloem et al. 1997). MRI has dramatically improved the pre-operative staging of these tumors. As a result, there has been a major reduction in the incidence of mutilating surgery. Limb-sparing procedures are now commonly used for primary osseous or soft-tissue neoplasms, with resulting improvement in the quality of life for these survivors. Patients with primary osseous and soft-tissue neoplasms have also benefi ted enormously from developments in initial chemotherapies. Initial chemotherapy is administered prior to tumor resection and has led to improved surgical outcomes and improved survival. For some tumors and/or stages, response to this initial therapy correlates positively with overall survival, in which case measuring this response as precisely and accurately as possible is vital. MRI is also important in screening for the presence of residual or recurrent tumor. The detection of small recurrent or residual tumor, following initial treatment, poses a challenge. The problem is further complicated by susceptibility artifacts on CT or MR images arising from reconstructive hardware or metallic particles from surgical instruments. In spite CONTENTS