A generalized sidelobe canceler (GSC) approach is proposed for medical ultrasound imaging. The approach uses a set of adaptive weights instead of traditional non-adaptive weights, thus suppressing the interference and noise signal of echo data. In order to verify the validity of the proposed approach, Field II is applied to obtain the echo data of synthetic aperture (SA) for 13 scattering points and circular cysts. The performance of GSC is compared with SA using boxcar weights and Hamming weights, and is quantified by the full width at half maximum (FWHM) and peak signal-to-noise ratio (PSNR). Imaging of scattering point utilizing SA, SA (hamming), GSC provides FWHMs of 1.13411, 1.68910, 0.36195 mm and PSNRs of 60.65, 57.51, 66.72 dB, respectively. The simulation results of circular cyst also show that GSC can perform better lateral resolution than non-adaptive beamformers. Finally, an experiment is conducted on the basis of actual echo data of an ultrasound system, the imaging result after SA, SA (hamming), GSC provides PWHMs of 2.55778, 3.66776, 1.01346 mm at z=75.6 mm, and 2.65430, 3.76428, 1.27889 mm at z=77.3 mm, respectively.
Акустический журнал, 63, № 2, с. pp. 229-236 (2017) | Рубрика: 13.04
Jurkonis R., Sakalauskas A., Lukoševičius A., Maciulevičius M., Tamoši~-unas M., Šatkauskas S. «Mapping Microbubble and Ultrasound Spatio-temporal Interaction by M-mode Imaging: The Study of Feasibility» Акустический журнал, 65, № 2, с. pp. 216-225 (2019)
Ultrasound (US) and microbubble (MB) interaction is an important factor in the research of bioacoustics, as well as targeted drug and gene delivery. In this study, we demonstrate the feasibility of pulse–echo M-mode imaging system to be used for the visualization and quantification of US–MB interaction in both spatial and temporal dimensions. The system incorporates an exposure chamber with the cell–MB suspension, a 2.7 MHz focused US transducer, a US pulser–receiver and the customized LabView software. The results of cell and MB interaction obtained after M-mode image analysis have showed the US–MB interaction to be non-uniform in space and non-stationary in time. In order to quantify the spatio-temporal US–MB interaction, we have introduced the time function of spatial homogeneity dynamics. We have observed that the effective duration of interaction can be characterized at the predefined threshold of spatial homogeneity. For example, at the US excitation of 360 kPa peak negative pressure (15 bursts transmitted at 80 Hz pulse repetition frequency), the US–MB interaction persists for more than 5 seconds in the range at 4 mm depth of the exposure chamber with more than 50% of homogeneity. The system proposed in this assay is feasible for the characterization of US–MB interaction and can be exploited to optimize the MB concentration and/or the US excitation parameters.
Акустический журнал, 65, № 2, с. pp. 216-225 (2019) | Рубрика: 13.04