Therapeutic response in musculoskeletal soft tissue sarcomas: evaluation by MRI

This paper provides a literature review of the use of magnetic resonance imaging in monitoring the treatment response of soft tissue sarcomas (STS). The basic classification and physiology of the soft tissue tumor is introduced. Then, the major treatment options for STS are summarized with brief coverage of possible responses and grading systems. Four major branches of MR imaging techniques are covered, including conventional T1- and T2-weighted imaging, contrast-enhanced MR imaging, MR diffusion and perfusion imaging, and MR spectroscopy, with a focus on the tumor microenvironment. Although this literature survey focuses on recent clinical developments using these MR techniques, research venues in pre-clinical studies, as well as in potential applications other than soft tissue sarcomas, are also included when comparable and/or mutually supporting. Examples from other less-discussed MR imaging modalities are also briefly covered, not only to complement but also to expand the scope and depth of information for various kinds of lesions.