Preliminary study of ultrasonographic tissue quantification of the breast using the acoustic radiation force impulse (ARFI) technology

Highlights: → We confirmed the reproducibility of the Virtual Touch tissue quantification. → Operator dependence is negligible when assessing the stiffness of breast lesions. → Tissue quantification is promising technique for the diagnosis of breast lesions. -- Abstract: Purpose: To investigate the shear wave velocity of normal breast tissue and breast lesion using acoustic radiation force impulse (ARFI) technology. Materials and methods: This retrospective study was conducted with the approval of the institutional review board. Shear wave velocity was measured using a linear array transducer with a bandwidth of 4-9 MHz and Virtual Touch tissue quantification (Siemens Medical Solutions, Mountain View, CA, USA) in 50 patients. First, the values of the shear wave velocity were determined in the normal tissues. Then, the changes in the shear wave velocity while applying external compression on the breast were determined. For the differential diagnosis of breast lesions, the shear wave velocities of 30 mass lesions (13 benign and 17 malignant lesions) classified as BI-RADS category 4 were measured. Results: The mean shear wave velocities in the subcutaneous fat and the mammary gland parenchyma were 2.66 m/s and 3.03 m/s, respectively (p = 0.0006). The mean shear wave velocity measured while applying external compression was 3.33 m/s for subcutaneous fat (p < 0.0001), and 3.84 m/s for the mammary gland parenchyma (p < 0.0001). In 4 of malignant cases, the shear wave velocity was not indicated (displayed as X.XX; unmeasurable state). The mean shear wave velocity of the 13 malignant lesions (4.49 m/s) was higher than that of benign lesions (2.68 m/s) (p < 0.01). Conclusions: ARFI tissue quantification is thought to be a potentially promising ultrasound technique for the diagnosis of breast lesions, but further investigation is required to identify the most appropriate method of measurement.