Whole-Body MR Imaging: Musculoskeletal Applications

Whole-body magnetic resonance (MR) imaging has been evaluated in many oncologic and rheumatologic indications and is emerging as a powerful tool for early diagnosis, quantification of disease extent, therapeutic decision making, and treatment monitoring. This development of whole-body MR imaging comes at a time marked by the rapid development of modern, powerful, but expensive and potentially toxic treatments. In oncology, the feasibility and diagnostic performance of diffusion-weighted imaging (DWI) applied to the whole body largely contribute to the effectiveness of whole-body MR imaging. The concurrent acquisition of both anatomic and functional DWI sequences provides an intrinsically "hybrid" dimension to whole-body MR imaging studies, allowing a sensitive and specific diagnosis of bone involvement by metastases, multiple myeloma, and lymphoma, and evaluation of treatment response, representing a promising biomarker. In arthritis of the axial skeleton, mainly spondyloarthropathies, whole-body MR imaging reveals additional lesions compared with limited axial (lumbar and pelvic) studies, especially in the thoracic spine and thoracic wall, pelvic and shoulder girdles, and peripheral entheses and joints. This article provides an overview of technical aspects of whole-body MR imaging and practical recommendations for the interpretation of whole-body MR imaging studies. It reviews the currently established and potential indications for whole-body MR imaging in oncology and rheumatology, discussing the diagnostic performance, advantages, and drawbacks of the technique, and its potential roles in comparison to other imaging modalities.