A 50 MHz microcomputer-based data acquisition and analysis system for ultrasound tissue characterization

Abstract

The authors present an ultra-high-speed microcomputer-based data acquisition and analysis system to be coupled to an ultrasound scanner machine. The primary application of the system described is to measure the backscattered ultrasound energy from human liver tissue and use this measurement to differentiate between normal and abnormal liver tissue. The system digitizes the ultrasound signal with a sample rate of 50 megasamples/second and stores the digitized data in an intermediate storage. When the storage is full, the data are transferred to an IBM-PC where a fast Fourier transform algorithm is applied to calculate the power spectrum of the ultrasound signal. The measurement of the power spectrum is used to estimate the acoustic attenuation and backscattering coefficients of the tissue as function of the frequency. By investigating these coefficients, the biological status of the tissue (normal or abnormal) can be determined. The six main system components are described in some detail: the conditioning circuit, the analog/digital converter unit, the latching circuit unit, the intermediate storage unit, the communication unit, and the control-delay circuit unit.<>