Imaging of Soft-Tissue Musculoskeletal Masses: Fundamental Concepts

Abstract

Radiologic evaluation of musculoskeletal soft-tissue masses has changed dramatically with the continued improvements in imaging technology. The integration of advanced imaging has provided the radiologist with a wide range of assessment tools, but as with all powerful arsenals, selection and application of the appropriate imaging method can be problematic. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically, the basic objectives of this assessment have remained constant: diagnosis and staging. The basic principles for evaluating musculoskeletal soft-tissue masses and achieving these objectives have not changed. This article addresses application of the current imaging methods to assessment of soft-tissue musculoskeletal masses, emphasizing fundamental concepts. We do not intend to provide a comprehensive review of imaging techniques, but rather to provide a useful review of the concepts needed to select the appropriate initial imaging method, magnetic resonance (MR) imaging field of view, MR imaging sequences, contrast material requirements, and rapid image acquisition techniques. We also address use of the new quantitative techniques of chemical shift and diffusion-weighted imaging. Finally, we review the current uses of computed tomography and ultrasonography. Although the choices available for imaging evaluation of musculoskeletal masses have changed dramatically within the past decade, appropriate application of the fundamental concepts of imaging will maximize the diagnostic utility of imaging examinations. RSNA, 2016.

MR Imaging of Muscle Trauma: Anatomy, Biomechanics, Pathophysiology, and Imaging Appearance

“…Mature lesions, typically 6 or more weeks after injury, demonstrate the distinctive zonal organization of myositis ossificans, with a peripheral ring of mature ossification at its margins surrounding a central cellular core (81) (Fig 35). At US, acoustic shadowing develops at the osseous interface at this stage, obscuring the center of the lesion.…”

Applications of PET‐MRI in musculoskeletal disease

“…MRI is the gold standard modality for assessing T‐stage given its excellent soft tissue contrast, high spatial resolution, and multiplanar capability. It is critical in preoperative and radiation planning, depicting tumor relationship to neurovascular structures, fascial planes, muscular compartments, and adjacent joints . Of interest, a retrospective study examining the diagnostic accuracy of FDG PET/CT and conventional imaging (including MRI) of a heterogeneous cohort of 117 BS and STS showed slightly better T‐staging by FDG PET/CT (overall accuracy 96%) compared with conventional imaging (94% accuracy) .…”

“…The addition of novel MRI techniques such as DWI with apparent diffusion coefficient (ADC) mapping, dynamic contrast enhancement (DCE), and MRS may improve diagnostic accuracy compared with conventional MRI . Combining these with metabolic measures such as standardized uptake values (SUV), total lesion glycoslysis (TLG), and metabolic tumor volume (MTV) provides powerful multiparametric evaluation.…”

“…It is critical in preoperative and radiation planning, depicting tumor relationship to neurovascular structures, fascial planes, muscular compartments, and adjacent joints. [29][30][31] Of interest, a retrospective study examining the diagnostic accuracy of FDG PET/ CT and conventional imaging (including MRI) of a heterogeneous cohort of 117 BS and STS showed slightly better T-staging by FDG PET/CT (overall accuracy 96%) compared with conventional imaging (94% accuracy). 32 FDG PET has also been shown to help identify tumor-free surgical margins before surgical resection.…”

“…The addition of novel MRI techniques such as DWI with apparent diffusion coefficient (ADC) mapping, dynamic contrast enhancement (DCE), and MRS may improve diagnostic accuracy compared with conventional MRI. 30,34,35 Combining these with metabolic measures such as standardized uptake values (SUV), total lesion glycoslysis (TLG), and metabolic tumor volume (MTV) provides powerful multiparametric evaluation. Indeed, the combination of metabolic and spectroscopic evaluation on FDG PET-MRI has been explored in STS, 36 and a radiomics model combining texture features from FDG PET-MRI has been used to identify factors most predictive of lung cancer metastases in 51 patients with extremity STS.…”