Optimising phase and amplitude modulation schemes for imaging microbubble contrast agents at low acoustic power

Eckersley, Robert J.; Chin, Chien Ting; Burns, Peter N.

doi:10.1016/j.ultrasmedbio.2004.10.004

Cited by 222 publications

(162 citation statements)

References 17 publications

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“…low mechanical indices) microbubbles produce non-linear (harmonic) echoes compared to the mostly linear tissue scattering. Different pulse streams and processing algorithms were designed to make use of this physical phenomenon and remove tissue related background from CEUS signals [22]. In addition, different priors on the relatively slow movement of the tissue [23] and its spatial coherence [21] are used in order to design temporal and spatiotemporal (SVD based) filters for tissue clutter removal.…”

Section: A Clutter Removal In Ceus Imagingmentioning

confidence: 99%

Fast Vascular Ultrasound Imaging With Enhanced Spatial Resolution and Background Rejection

Bar‐Zion

Tremblay-Darveau

Solomon

et al. 2017

IEEE Trans. Med. Imaging

108

101

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Abstract-Ultrasound super-localization microscopy techniques presented in the last few years enable non-invasive imaging of vascular structures at the capillary level by tracking the flow of ultrasound contrast agents (gas microbubbles). However, these techniques are currently limited by low temporal resolution and long acquisition times. Super-resolution optical fluctuation imaging (SOFI) is a fluorescence microscopy technique enabling sub-diffraction limit imaging with high temporal resolution by calculating high order statistics of the fluctuating optical signal. The aim of this work is to achieve fast acoustic imaging with enhanced resolution by applying the tools used in SOFI to contrast-enhance ultrasound (CEUS) plane-wave scans. The proposed method was tested using numerical simulations and evaluated using two in-vivo rabbit models: scans of healthy kidneys and VX-2 tumor xenografts. Improved spatial resolution was observed with a reduction of up to 50% in the full width half max of the point spread function. In addition, substantial reduction in the background level was achieved compared to standard mean amplitude persistence images, revealing small vascular structures within tumors. The scan duration of the proposed method is less than a second while current superlocalization techniques require acquisition duration of several minutes. As a result, the proposed technique may be used to obtain scans with enhanced spatial resolution and high temporal resolution, facilitating flow-dynamics monitoring. Our method can also be applied during a breath-hold, reducing the sensitivity to motion artifacts.

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Section: A Clutter Removal In Ceus Imagingmentioning

confidence: 99%

Fast Vascular Ultrasound Imaging With Enhanced Spatial Resolution and Background Rejection

Bar‐Zion

Tremblay-Darveau

Solomon

et al. 2017

IEEE Trans. Med. Imaging

108

101

View full text Add to dashboard Cite

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“…Data were acquired with two different ultrasound sequences at different time instances during the experiment. A contrast sequence using an amplitude modulation techniques to excite the microbubbles in an nonlinear regime (which attenuate the tissue signal [10], [11]) and a standard B-mode sequence used to display the tissue. The frame rate in both sequences was 50 Hz.…”

Section: A Equipmentmentioning

confidence: 99%

Robust microbubble tracking for super resolution imaging in ultrasound

Hansen

Villagomez-Hoyos

Brasen

et al. 2016

2016 IEEE International Ultrasonics Symposium (IUS)

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Abstract-Currently ultrasound resolution is limited by diffraction to approximately half the wavelength of the sound wave employed. In recent years, super resolution imaging techniques have overcome the diffraction limit through the localization and tracking of a sparse set of microbubbles through the vasculature. However, this has only been performed on fixated tissue, limiting its clinical application. This paper proposes a technique for making super resolution images on non-fixated tissue by first compensating for tissue movement and then tracking the individual microbubbles. The experiment is performed on the kidney of a anesthetized Sprage-Dawley rat by infusing SonoVue at 0.1× original concentration. The algorithm demonstrated in vivo that the motion compensation was capable of removing the movement caused by the mechanical ventilator. The results shows that microbubbles were localized with a higher precision, reducing the standard deviation of the super localizations from 22 µm to 8 µm. The paper proves that the restriction of completely fixated tissue can be eliminated, when making super resolution imaging with microbubbles.

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“…Such systems use phase and amplitude modulation of the transmitted ultrasound waveform, coupled with subtraction methods to cancel out linear backscatter from tissue, to specifically detect the nonlinear microbubble signal. 18,19 Microbubbles 1 to 4 m in size are used both clinically and in experimental models as red cell tracers during ultrasound imaging. 20 For molecular imaging, the microbubble surface is modified to display ligands that cause microbubble binding to specific endothelial epitopes associated with disease processes.…”

Section: Ultrasound Imagingmentioning

confidence: 99%

“…Therefore, 11 C probes, although capable of providing fundamental insight, are unlikely to reach a broad utilization. 18 F has a longer half-life (Ϸ2 hours) and provides a more feasible alternative PET radioisotope for local distribution. Recently, investigators have been using even longer half-life PET radionuclides like 64 Cu, 76 Br, or 124 I that facilitate complex syntheses and more widespread radiotracer distribution.…”

Section: Molecular Probe Development and Designmentioning

confidence: 99%

“…63 Thus, this imaging approach is a prime example of an enzyme-specific radiolabeled probe that uses an enzyme-metabolic trapping mechanism to amplify the signal in target tissue, facilitating in vivo imaging. Another example of this radiolabeling scheme include the various fluorine-18 labeled fatty acid analogs, 14-(R,S)- 18 F-fluoro-6-thiaheptadecanoic acid, and 18 F-fluoro-thia-palmitate, whose myocardial kinetics in general parallel fatty acid uptake and ␤-oxidation. 79 -82 Over the past 25 years, numerous radiotracers have been developed to assess myocardial fatty acid metabolism with SPECT.…”

Section: Metabolic Imagingmentioning

confidence: 99%

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