The clinical utility of emerging ultrasound techniques in the assessment of musculoskeletal soft tissue masses
By Cai Sihui, Singapore General Hospital
Objectives
• To explore the use of emerging ultrasound techniques, namely Superb Microvascular Imaging (SMI), Strain Elastography (SE) and Shear-wave Elastography (SWE) in the assessment of musculoskeletal soft tissue
masses
• To highlight the importance in selecting the appropriate assessment tool when assessing musculoskeletal soft tissue masses
• To illustrate the sonographic characteristics of benign and malignant lesions using these techniques where available
• To present a systematic approach for sonographic evaluation of musculoskeletal soft tissue masses with the incorporation of these techniques as problem solving tools
Methods
Studies performed in the institution were retrospectively reviewed. Appropriate scenarios where these techniques might be feasible would be presented and the potential pitfalls would be discussed.
Results
With the advances of ultrasound technology, SMI, SE and SWE are increasingly used for the assessment of soft tissue masses. SMI utilises adaptive algorithm to remove clutter artefacts while displaying low velocity flow.
SMI also enhances visualisation of intra- and peri-lesional minute vessels with slow flow, allowing detection of tumour angiogenesis. Both SE and SWE provide additional useful information on lesions’ stiffness compared to conventional US and minimise subjective interpretation of lesion hardness/stiffness based on palpation. These emerging techniques value-add to narrow down differential diagnoses as malignant lesions tend to be stiffer than their benign
counterparts.
We provide an illustration to guide the application of these emerging techniques. Potential pitfalls or limitations are; excessive transducer pressure, resulting in reduction of SMI signal and increased SWE stiffness values; deep or larger-than-probe-footprint lesions, which limit accurate SE and SWE assessment.
Conclusion
SE, SWE and SMI are excellent adjunctive tools in the diagnostic test of soft tissue masses. Identifying characteristics of aggressive masses, such as intra-lesional vascularity, is important to allow timely clinical management. An effective systematic approach using appropriate technique application in image acquisition can minimise potential pitfalls.