A method for estimating the size of scatterers in ultrasound imaging

A number of diseases, such as breast, thyroid, and liver steatosis cancers, are characterized by changes in the size of the body's cells. Such changes are difficult to diagnose with current medical imaging tools, and the biopsies required to make a definitive diagnosis are expensive for the health care system and painful for the patient. At the same time, ultrasound imaging stands out from other diagnostic methods due to its prevalence, absence of harmful radiation and the possibility of real-time operation. Therefore, the development of methods for estimating the size of scatterers based on the principles of ultrasound imaging is relevant. It is known that the statistics of ultrasonic signals is described by the Rice distribution. However, until recently the estimation of parameters of the Rice distribution was difficult because of the necessity to calculate the Bessel function. To develop a new method for estimation of scatterer sizes in ultrasound imaging based on the calculation of the parameters of the Rice distribution without calculating the Bessel function. The developed method of scatterers size estimation was tested by numerical simulation of ultrasonic oscillation propagation in the medium. The simulations showed that estimating the ratio of the parameters σ and A of the Rice distribution while varying the scatterer size allows us to identify a decreasing linear trend that can be used to estimate the scatterer size. In an experiment using a signal at a carrier frequency of 5 MHz and a duration of 0.7 μs, it was possible to perform size estimation in the range from 41 to 706 μm, which is 4 to 69 % with respect to the duration of the probing pulse. The operation of the method is possible with the size of a square sliding window with side up to 2 mm. The results of the study can be used in the development of ultrasonic medical diagnostic systems with the mode of scatterer size estimation.