Ultrasonic b-scan imaging with adaptive beamformation using aberration correction

Abstract

The effectiveness of adaptive beam formation using aberration correction has been demonstrated in ultrasonic b-scans of liver-mimicking scattering phantoms imaged with and without an intervening aberrator that produced wavefront distortion comparable to that of abdominal wall. Images of 4 mm diam spherical features (either positive or negative contrast lesions or scatterer-free cysts) in the uniform scattering background of the phantoms were produced at 3.0 MHz with a two-dimensional (80×80-element) array transducer system. Time-shift aberration was estimated from the scattering data and used to compensate both transmit and receive waveforms. Image improvements were assessed by comparison of feature contrast with and without aberration correction in individual images and by comparison of intensities in averages of independent, statistically identical images. Feature contrasts and borders were visibly and measurably improved, sometimes to near the water path results, using aberration correction, particularly when both transmit and receive corrections were applied. An efficient implementation of aberration correction was achieved by correction of multiple image scan lines with a single aberration estimate. Aberration correction using estimates from one-seventh the number of scan lines in 8 mm wide images produced improvements comparable to those achieved by individually estimating and correcting aberration in every scan line.

Acoustical News—USA

“…The phantoms were jointly developed by the laboratories of Professor Waag and Professor Ernest Madsen of the University of Wisconsin. The first-and second-order statistics of spatial variations in the energy and arrival times of ultrasound pulses distorted by these phantoms are comparable to previous measurements of aberration produced by transmission through human abdominal wall specimens ͑Lacefield, Pilkington, and Waag, 2002͒. The phantoms are distinguished from more idealized physical models of aberration by the inclusion of three-dimensionally distributed aberrating structures and by the production of statistically realistic energy fluctuations.…”