Initial experience with a new ultrasound imaging technique to measure tissue viscoelasticity

Introduction

SuperSonic Imagine has developed a unique ultrasound platform that can image supersonic shear wave (SSW) propagation and determine quantitative elastic properties of tissue.

The accuracy of this system's elastography was evaluated with the characterization of breast nodules.

Methods

Thirty-six breast nodules (4 mm to 22 mm, 25 benign and 11 malignant; BI-RADS category 3 = six cases, category 4 = 21 cases, category 5 = seven cases and category 6 = two cases) were prospectively evaluated in 34 patients (age 42 to 71 years; mean age, 59 years). Radiohistological correlations were available for all cases (fine-needle aspiration = 10 and/or core biopsies = 26). Data were processed to reconstruct the SSW colour images and to obtain quantitative elasticity in kiloPascal units.

Results

SSW elastography detected all breast nodules, and the 1 mm system resolution facilitated the detection of small or isoechoic lesions. The mean elasticity of malignant lesions was significantly higher than the mean value of benign lesions (170 ± 41.6 kPa versus 62 ± 21 kPa). Owing to different displacement rates of solid versus cystic material, this technique correctly characterized the cystic component of complicated cysts in B-mode ultrasound.

Conclusion

Quantitative SSW elastography allows a reliable, reproducible and user-independent measurement of tissue elasticity, thus providing a complementary tool for breast lesion diagnosis.