Aberrations in ultrasound images are not just noise

“What am I looking at?” asked every soon-to-be parent at their ultrasound appointments. Many of the aberrations in ultrasound imaging are not random, but actually carry information. A better utilization of these otherwise superfluous signals can not only help improve the quality of ultrasound images, but may reveal additional information about the measured tissue.

Weber et al. present a way to perform ultrasound differential phase contrast (DPC) imaging. Based on a conventional ultrasound imaging device, the method is in essence a sonic version of the optical differential interference contrast method. By creating two laterally sheared copies of randomly scattered sonic waves, the technique can reveal aberrating structures in the sample through the phase differences in the combined reflection, or echo, from the two waves.

As a result, DPC can offer phase contrast in the transverse direction normally missing in conventional B-mode ultrasound imaging, without requiring additional hardware or intensive computation.

They demonstrated the capability of the method by performing ultrasound measurements on cylinders and spheres with various diameters and speed-of-sound embedded in hydrogel, using two different tissue simulation phantoms.

So far, the authors have only demonstrated the principal of DPC imaging with relatively homogeneous samples containing simple structures. They plan to continue this study with more complex samples that more closely mimic soft tissue in humans, with the hope of eventually translating their method to the clinic.

Source: “Ultrasound differential phase contrast using backscattering and the memory effect,” by Timothy D. Weber, Nikunj Khetan, Ruohui Yang, and Jerome Mertz, Applied Physics Letters (2021). The article can be accessed at https://doi.org/10.1063/5.0048071 .