3D ultrasound imaging in frequency domain based on concepts of array beam and synthetic aperture

Abstract

The high frame rate (HFR) imaging method has the ability to achieve a high frame rate. In this method, only one transmission is required to construct a frame of image. In our previous work, using a moved one-dimensional (1D) array transducer, a three-dimensional (3D) ultrasound imaging method in frequency domain was developed. This imaging method was designed based on the concepts of array beam and synthetic aperture, which can simplify the two-dimensional (2D) array transducer. In this paper, based on array beam and synthetic aperture, the HFR imaging method is demonstrated from a novel view. From this view, the relationship between the HFR imaging method and synthetic aperture is established with the weighting function of array beam. Besides, the HFR imaging method, the imaging method with a moved 1D array transducer, and the synthetic aperture imaging method with a moved single element transducer are unified in the same analytical method with different weighting functions. The same frequency domain signal processing flow can be applied to these imaging methods. Comparisons to these imaging methods are implemented with simulations. Simulation results show that, in the imaging depth of 45 mm, the resolutions calculated as the total width of the -6 dB main lobe in x-direction are 1.099 mm, 1.056 mm and 0.596 mm for the methods with 1D transducer, 2D transducer and the single element transducer, respectively. The resolution in y-direction is 1.054 mm for the methods with 2D transducer, and 0.565 mm, 0.593 mm for the 1D and single element transducers, respectively. The resolutions in z-direction are 0.493 mm, 0.451 mm and 0.452 mm for the 2D, 1D and single element transducers, respectively. The resolution in the moved-direction is improved with a moved transducer, but the contrast of the image is decreased.

Keywords: 3D ultrasound imaging; Array beam; Fourier transform; Synthetic aperture.