Blocked Elements in 1-D and 2-D Arrays—Part II: Compensation Methods as Applied to Large Coherent Apertures

Jakovljevic, Marko; Bottenus, Nick; Kuo, Lily; Kumar, Shalki; Dahl, Jeremy J.; Trahey, Gregg E.

doi:10.1109/tuffc.2017.2683562

Cited by 9 publications

(1 citation statement)

References 18 publications

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“…Furthermore adding blocked elements to the beamformer reduced vessel contrast by 19% and vessel contrast to noise ratio by 10%. Subsequently a blocked element compensation method was proposed and shown to reduce reverberation clutter by 5 dB [13]. Using the two dimensional Fullwave simulation tool in the human abdomen we have previously shown that reverberation clutter is a principal source of image degradation at the fundamental frequency [2].…”

Section: Introductionmentioning

confidence: 99%

Ultrasound imaging with three dimensional full-wave nonlinear acoustic simulations. Part 2: sources of image degradation in intercostal imaging

Pinton¹

2020

Preprint

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Full-wave simulations are applied to an intercostal imaging scenario to determine the sources of fundamental and harmonic image degradation with respect to aberration and reverberation. These simulations are based on Part I of this two part paper, which established the full-wave simulation methods to generate realistic ultrasound images based directly on the first principles of wave propagation in the human body. The ultasound images are generated based on the first principles of propagation and reflection. By relying on first priniples of the three dimensional wave propagation physics the interplay between distributed aberration and reverberation clutter can be fully appreciated. Three imaging scenarios that would not be realizable in vivo are investigated in silico. First, the ribs were completely removed and replaced with fat. Then, the ribs were maintained in their anatomically correct configuration to yield a reference image. Finally the ribs were placed closer together in elevation. The propagation based B-mode images show that of these three scenarios the second, anatomically correct configuration, has the best contrast-to-noise ratio. This is due to two competing effects. First it is shown that the ribs effectively apodize the fundamental and harmonic beams by 3-5 dB. This effect alone would predict an improvement in image quality. However, the B-mode image quality, measured by the contrast-to-noise ratio degrades by 8%. To fully explain these changes, it is shown that a second effect, multiple reverberation, must be taken into account. A point spread function analysis shows that when the ribs are placed closer together they also generate significantly more reverberation clutter (by 2.4 to 2.9 dB), which degrades the image quality even though the beamplot has lower sidelobes. In this intercostal imaging scenario the effects of the ribs on beam shape and reverberation are therefore in competition in terms of image quality and there is an optimal acoustic window that balances them out. This simulation tool and image quality analysis could be applied to other imaging configurations and in other areas of the body.

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Section: Introductionmentioning

confidence: 99%

Ultrasound imaging with three dimensional full-wave nonlinear acoustic simulations. Part 2: sources of image degradation in intercostal imaging

Pinton¹

2020

Preprint

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Studying the Origin of Reverberation Clutter in Echocardiography: In Vitro Experiments and In Vivo Demonstrations

Fatemi

Berg

Rodríguez-Molares

2019

Ultrasound in Medicine & Biology

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Clutter in echocardiography hinders the visualization of the heart and reduces the diagnostic value of the images. The detailed mechanisms that generate clutter are, however, not well understood. We present five different hypotheses for generation of clutter based on reverberation artifact with a focus on apical four-chamber view echocardiograms. We demonstrate the plausibility of our hypotheses by in vitro experiments and by comparing the results with in vivo recordings from four volunteers. The results show that clutter in echocardiography can be originated both at structures that lie in the ultrasound beam path and at those that are outside the imaging plane. We show that reverberations from echogenic structures outside the imaging plane can make clutter over the image if the ultrasound beam gets deflected out of its intended path by specular reflection at the ribs. Different clutter types in the in vivo examples show that the appearance of clutter varies, depending on the tissue from which it originates. The results of this work can be applied to improve clutter reduction techniques or to design ultrasound transducers that give higher quality cardiac images. The results can also help cardiologists have a better understanding of clutter in echocardiograms and acquire better images based on the type and the source of the clutter.

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Improving plane wave ultrasound imaging through real-time beamformation across multiple arrays

Foiret

Cai

Bendjador

et al. 2022

Sci Rep

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Ultrasound imaging is a widely used diagnostic tool but has limitations in the imaging of deep lesions or obese patients where the large depth to aperture size ratio (f-number) reduces image quality. Reducing the f-number can improve image quality, and in this work, we combined three commercial arrays to create a large imaging aperture of 100 mm and 384 elements. To maintain the frame rate given the large number of elements, plane wave imaging was implemented with all three arrays transmitting a coherent wavefront. On wire targets at a depth of 100 mm, the lateral resolution is significantly improved; the lateral resolution was 1.27 mm with one array (1/3 of the aperture) and 0.37 mm with the full aperture. After creating virtual receiving elements to fill the inter-array gaps, an autoregressive filter reduced the grating lobes originating from the inter-array gaps by − 5.2 dB. On a calibrated commercial phantom, the extended field-of-view and improved spatial resolution were verified. The large aperture facilitates aberration correction using a singular value decomposition-based beamformer. Finally, after approval of the Stanford Institutional Review Board, the three-array configuration was applied in imaging the liver of a volunteer, validating the potential for enhanced resolution.

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Blocked Elements in 1-D and 2-D Arrays—Part II: Compensation Methods as Applied to Large Coherent Apertures

Cited by 9 publications

References 18 publications

Ultrasound imaging with three dimensional full-wave nonlinear acoustic simulations. Part 2: sources of image degradation in intercostal imaging

Ultrasound imaging with three dimensional full-wave nonlinear acoustic simulations. Part 2: sources of image degradation in intercostal imaging

Studying the Origin of Reverberation Clutter in Echocardiography: In Vitro Experiments and In Vivo Demonstrations

Improving plane wave ultrasound imaging through real-time beamformation across multiple arrays

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