Value added: functional MR imaging in management of bone and soft tissue sarcomas

Purpose of review MRI plays a crucial role in the initial diagnosis, treatment planning, and long-term management of bone and soft tissue sarcomas. Technological advances have enabled improvements in both delineation of anatomic detail, and in functional imaging techniques that interrogate tissues at the cellular level. This bears particular relevance in sarcomas as morphological parameters alone do not necessarily correlate with treatment response and prognosis. Here, we describe recent developments in advanced MRI techniques, including chemical-shift MRI, diffusion-weighted imaging (DWI), MR spectroscopy (MRS), and dynamic contrast enhanced (DCE) MRI. Recent findings Chemical-shift MRI allows robust discrimination of marrow infiltrating neoplasms from benign red marrow. DWI reveals tumor cellularity, and aids in distinguishing benign and malignant tumors along with the assessment of treatment response. MRS is technically challenging in the musculoskeletal system, but shows promise as a means to noninvasively assess metabolic aberrations in a variety of sarcomas. DCE is particularly suited to treatment response evaluation, in which traditional size-based assessment criteria may underestimate efficacy in clinical trials. Summary Functional MRI techniques offer novel imaging biomarkers that effectively complement conventional MRI in the assessment of bone and soft tissue sarcomas at all stages of patient care.