Assessing hardness to make things easy! Ultrasonography with elastographic evaluation of soft tissue tumours.

Abstract

Introduction: Soft tissue tumours are a heterogeneous group of lesions. However, their diagnoses revolve around pathological evaluation with limited role of imaging.

Purpose: 1. To non-invasively classify soft tissue tumours into benign and non-benign subtypes based on ultrasonography with use of shear wave elastography. 2. To study interobserver variation in elastographic evaluation of the soft tissue tumours.

Materials and methods: In a prospective study, various soft tissue lesions in 51 study participants were sonographically assessed based on shape, margin, echogenicity, internal cystic areas and elasticity. These imaging characteristics were correlated with histopathological subtypes.

Results: Based on gray scale parameters, out of 36 histopathologically proven non-benign lesions, a total of 30 (83.33%) had lobulated/ irregular shape, 24 (66.67%) had ill-defined margins, 30 (83.33%) were heterogenous in echogenicity. The difference between the maximum and minimum elasticity values (E_max - E_min) implying elastic heterogeneity within a lesion shows statistically significant difference (p < 0.05), however Maximum and minimum elasticity as individual parameters did not show statistically significant difference between benign and non-benign lesions. Also, Karl pearson's correlation coefficient was calculated to be 0.9 for maximum elasticity and 0.7 for minimum elasticity within a lesion depicting high interobserver reliability.

Conclusion: Shape, margin and echogenicity on gray scale imaging and elastic heterogeneity (E_max - E_min) are helpful predictors to differentiate benign from non-benign lesions. Shear wave elastography is a reproducible technique with good interobserver agreement. However, further studies are needed on elastic heterogeneity for confident classification of lesion.