Improved detectability of hypoechoic regions with short-lag spatial coherence imaging: experimental validation

The ability of an ultrasound system to differentiate signals in the presence of clutter is of key clinical importance. There are several sources of clutter but assessing their relative importance and developing methods of reducing them remain areas of active research. We have developed a novel method called short-lag-spatial-coherence (SLSC) imaging that allows formation of high quality ultrasound images in the presence of clutter. The method is based on the van-Cittert- Zernike theorem. Specifically, the images are formed by utilizing the spatial coherence of the pressure field at the surface of the transducer. We compare matched SLSC and B-mode images beamformed from simulated data and data acquired on human liver in vivo. SLSC images have higher contrast and CNR then their B-mode counterparts for all acoustic-noise conditions (low, medium, and high noise). Nevertheless, SLSC brings highest improvement of target detectability in the medium noise environment. When the received signal is saturated with noise, both Bmode and SLSC produce low-quality images.