Clinical Feasibility of Coherence-Based Beamforming to Distinguish Solid from Fluid Hypoechoic Breast Masses

Ultrasound imaging is often used in conjunction with mammography, particularly for patients with dense breast tissue, which causes an increased amount of acoustic clutter, obscuring lesions of interest, and contributing to the false positive rate of breast ultrasound. Coherence-based imaging methods, such as short-lag spatial coherence (SLSC) and robust short-lag spatial coherence (R-SLSC), display the coherence of backscattered ultrasound signals instead of their amplitude or brightness information, which offers opportunities to reduce acoustic clutter. This paper focuses on SLSC and R-SLSC beamforming applied to three in vivo masses in the female breast: (1) cyst, (2) fibroadenoma, and (3) ductal carcinoma in situ (DCIS). Contrast is improved by up to 7.8 dB with SLSC imaging and 4.86 dB with R-SLSC imaging in fluid-filled regions. However, contrast is degraded in coherence-based images of solid hypoechoic lesions because coherence is displayed in these regions with pathologically determined solid content. This interesting finding indicates the potential of coherence-based imaging to assist with the differentiation between solid and fluid-filled hypoechoic breast masses. Examples of duplex mode B-mode and R-SLSC images are shown to convey clinical potential.