Musculoskeletal Application of Ultrasound Elastography: Soft Tissue Lipoma

ABSTRACT

PURPOSE: To investigate the tissue elastic properties of soft tissue lipomas using real-time freehand elastography. MATERIALS AND METHODS: Conventional ultrasonography (US) and real-time freehand US elastography were performed in nine patients (MF = 45; mean age, 53 years; 29-64 years) with soft-tissue lipoma confirmed by surgical resection. The elastogram was color-coded by 256 scales according to the degree of strain induced by light compression. The relative strains for lipoma and surrounding soft tissue were measured and mean strains were examined by using a Wilcoxon signed rank test. RESULTS: The elastograms showed red to sky-blue color in all lipomas and predominantly black in surrounding soft tissue. The mean relative strain (+/-standard deviation) was 67.9+/-28.5, 77.1+/-25.3, 63.3+/-31.2, and 15.7+/-18.3 for total, intramuscular, and subcutaneous lipoma, and surrounding soft tissue, respectively. The mean strain of the lipoma was significantly higher than one of surrounding soft tissue (p = .008, Wilcoxon signed rank test). CONCLUSION: Real-time elastography yields characteristic elastographic features of soft tissue lipoma distinguishing from those of adjacent soft tissues.