Comparison of 3-D multi-lag cross- correlation and speckle brightness aberration correction algorithms on static and moving targets

Abstract

Phase correction has the potential to increase the image quality of 3-D ultrasound, especially transcranial ultrasound. We implemented and compared 2 algorithms for aberration correction, multilag cross-correlation and speckle brightness, using static and moving targets. We corrected three 75-ns rms electronic aberrators with full-width at half-maximum (FWHM) auto-correlation lengths of 1.35, 2.7, and 5.4 mm. Cross-correlation proved the better algorithm at 2.7 and 5.4 mm correlation lengths (P < 0.05). Static cross-correlation performed better than moving-target cross-correlation at the 2.7 mm correlation length (P < 0.05). Finally, we compared the static and moving-target crosscorrelation on a flow phantom with a skull casting aberrator. Using signal from static targets, the correction resulted in an average contrast increase of 22.2%, compared with 13.2% using signal from moving targets. The contrast-to-noise ratio (CNR) increased by 20.5% and 12.8% using static and moving targets, respectively. Doppler signal strength increased by 5.6% and 4.9% for the static and moving-targets methods, respectively.

The ultrasound brain helmet: new transducers and volume registration for in vivo simultaneous multi-transducer 3-D transcranial imaging

“…In recent years, many groups have presented techniques for correcting the wavefront aberration caused by the human skull. Our own group has previously used the multi-lag least-mean-square cross-correlation algorithm [17]–[19] to demonstrate the first successful in vivo transcranial phase corrections on a matrix array [20], [21]. Other techniques improving transskull focusing in diagnostic or therapeutic applications include using time-reversal mirrors to correct on a point target or induced cavitation bubble [22]–[25], computing element delays based on MRI or CT mapping of skull structure [26], [27], using shear mode conversion to lessen the effects of aberration because of the similarity between shear wave velocity in the skull (1400 m/s) and longitudinal wave velocity in brain tissue (1530 m/s) [28], [29], and making use of a contralateral source [30], [31].…”

Efficient Strategies for Estimating the Spatial Coherence of Backscatter

“…II). For example, phase aberration is often corrected by measuring the correlation between neighboring elements [4], [5]. The performance of the correction is strongly dependent on high correlation between the element signals.…”

Short-lag spatial coherence imaging on matrix arrays, Part II: Phantom and in vivo experiments

“…Ivancevich et al [10] implemented multi-lag least-squares cross-correlation and speckle brightness algorithms and compared their performance in correcting for physical aberrators using a single sparsely-sampled 2-D array. For the speckle-brightness method, no off-line processing was used; the entire method was implemented using the scanner beamforming routines.…”