Measurement of Ultrasonic Attenuation Within Regions Selected from B-Scan Images

This paper describes the calculation of absolute ultrasonic attenuation as a function of frequency by processing backscattered signals obtained from a clinical imaging instrument. The signal processing steps are developed from a mathematical model of scattering in an attenuating medium with random inhomogeneities. Attenuation data are derived from the imaging system by recording amplitude-compressed ultrasonic echo waveforms along with transducer position information and time-varying gain values. The input-output characteristics of the receiver are employed to remove the effects of compression and gain. Attenuation values are calculated for selected regions within scans of two tissue phantoms and a normal breast. The values agree with other independent measurements and illustrate the requirements for incorporating quantitative attenuation measurements with clinical imaging.