Estimation of scatterer size and acoustic concentration in sound field produced by linear phased array transducer

Abstract

Although there have been several quantitative ultrasound studies on the methods of estimation of scatterer size and acoustic concentration based on the analysis of RF signals for tissue characterization, some problems, e.g., narrow frequency bandwidths and complex sound fields, have limited the clinical applications of such methods. In this report, two types of ultrasound transducer are investigated for the estimation of the scatterer size and acoustic concentration in two glass bead phantoms of different weight concentrations of 0.25 and 2.50% and those in an excised pig liver. The diameters of the glass beads ranged from 5 to 63 µm with an average of 50 µm. The first transducer is a single element and the other is a linear phased array. A comparison of the estimations obtained using both transducers gives an insight into how these methods could be applied clinically. Results obtained using the two transducers were significantly different. One of the possible explanations is that beamforming could significantly affect the backscatter coefficient estimation, which was not taken into account.

Machine learning-enabled quantitative ultrasound techniques for tissue differentiation

“…where R is the axial distance from the transducer to the centre of the ROI, D is the active area of the 12 transducer elements, L is the gate length, is the reflectivity coefficient of a water and quartz interface, and is an attenuation compensation function for a gated signal [ 25 ]. Note that, following convention, all lengths were defined in mm.…”

Modification of gelatin and photocured 3D‐printed resin to prepare biomimetic phantoms for ultrasound‐guided minimally invasive surgeries

“…In previous studies, the attenuation of gelatin increased by adding glass beads under a similar ultrasonic frequency. [32][33][34] The tendency of SiO 2 addition was basically the same as with glass bead addition, but SiO 2 nanoparticles would present better stability and dispersion in gelatin phantoms. Burlew et al demonstrated that the addition of barium titanate nanoparticles increased the attenuation of agarose, PAA, and PDMS phantoms.…”

Estimation of aggregate size of red blood cell by introducing reference power spectrum measured for hemispherical ultrafine wire

“…This method has been applied for the analysis and classification of various tissues, such as, the liver, skin, lymph nodes, and blood. [18][19][20][21][22][23][24][25][26][27] Cloutier et al calculated the backscattering coefficient from the RF signal obtained from the vascular lumen and estimated the attenuation coefficient of tissues and the parameters indicating the structure of the RBC aggregates, [24][25][26] and showed the possibility of monitoring the systemic inflammatory state by in vivo measurements. 27) However, few studies using these methods have involved human subjects, and diagnosis using this method has not been clinically established.…”