Abstract
BackgroundIn ultrasound plane wave imaging (PWI), image details are often blurred by the off-axis artefacts resulting from high sidelobe. Recently plane wave compounding (PWC) is proposed as a promising technique for the sidelobe suppression in the PWI. However, its high demand for the frame number results in an obvious frame rate loss, which is intolerable in the ultrafast imaging modality. To reduce the number of frames required for compounding, coherence in the compounding frames should be exploited.MethodsIn this paper, we propose a global effective distance-based sidelobe suppressing method for the PWC with a limited frame number, where the global effective distance is introduced to measure the inter-frame coherence. Specifically, the effective distance is firstly computed by using a sparse representation-based algorithm. Then, the sidelobe localization is carried out on the basis of the effective distance. Finally, the target-dependent weighting factor is adopted to suppress the sidelobe.ResultsTo assert the superiority of our proposed method, we compare the performances of different sidelobe reduction methods on both simulated and experimental PWC data. In case of 5 steering angles, our method shows a 19 dB reduction in the peak sidelobe level compared to the normal PWC in the point spread function test, and the contrast ratio is enhanced by more than 10% in both the simulation and phantom studies.ConclusionsConsequently, the proposed method is convinced to be a promising approach in enhancing the PWC image quality.
Highlights
In ultrasound plane wave imaging (PWI), image details are often blurred by the off-axis artefacts resulting from high sidelobe
We propose a sidelobe suppressing method based on this new kind of distance, which is effective for the plane wave compounding (PWC) with a limited frame number
Simulated study Point spread function (PSF) Figure 5 shows the beamformed responses of 20 point targets located at depths from 10 to 45 mm using the normal PWC, the singular value decomposition (SVD) filter method and our proposed method over a 60 dB display dynamic range
Summary
In ultrasound plane wave imaging (PWI), image details are often blurred by the off-axis artefacts resulting from high sidelobe. Its high demand for the frame number results in an obvious frame rate loss, which is intolerable in the ultrafast imaging modality. The concept of ultrafast imaging using plane waves has been introduced in medical ultrasound for several years [1, 2]. In this modality, a plane wave is generated by applying flat delays to all elements of an ultrasound probe. The generated wave will insonify the whole area of interest In this way, the plane wave imaging (PWI) allows the acquisition of one full ultrasound image from a single shot. The PWI has shown potential in a wide range of real-time applications, such as the ultrafast elastography, cardiac activity monitoring and dynamic micro flow imaging [3,4,5,6].
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