Attenuation and Backscatter Estimation Using Video Signal Analysis Applied to B-Mode Images

Abstract

Most methods for in vivo quantitation of ultrasound attenuation and backscatter are not available clinically because they rely upon acquiring and analyzing radio frequency (rf) echo signals. This paper describes a technique to estimate ultrasound attenuation and backscatter from B-mode image data. The video signal analysis (VSA) technique utilizes images of a reference phantom, taken using the same instrument settings used to record images from the patient or sample, to account for effects of the transducer beam, system gain and signal processing on image data. A ‘gray-scale look-up table’ is derived to convert image pixel value data within a region of interest to echo signal amplitudes relative to echo signals from the same depth in the reference phantom. These relative echo levels enable estimates of attenuation and backscatter in the region of interest. VSA was used to quantify acoustic properties of test phantoms using 3 different clinical scanners and various transducers. The level of agreement between results obtained with different ultrasound imaging systems was very good. VSA attenuation and backscatter levels also compare favorably with attenuation coefficients and backscatter coefficients obtained using rf analysis.