Imaging of blood flow and oxygen state with a multi-segment optoacoustic ultrasound array

Merčep, Elena; Deán‐Ben, Xosé Luís; Razansky, Daniel

doi:10.1016/j.pacs.2018.04.002

Cited by 52 publications

(41 citation statements)

References 33 publications

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“…The integration of US-based imaging approaches into multimodal optoacoustic ultrasound (OPUS) platforms has previously been shown to complement and enhance advantages of the stand-alone modalities. The hybridization between optoacoustic (OA) and reflection-mode (pulse-echo) US imaging has recently been achieved with linear 27 , concave 28 , or multisegment arrays 29,30 . Multimodal endoscopic 31,32 and microscopic 33,34 imaging systems based on single-element transducers have also been suggested.…”

Section: Introductionmentioning

confidence: 99%

Transmission–reflection optoacoustic ultrasound (TROPUS) computed tomography of small animals

et al. 2019

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Rapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and spatiotemporal scales not covered by modern optical microscopy methods. Ultrasound imaging provides highly complementary information on elastic and functional tissue properties and further aids in enhancing optoacoustic image quality. We devised the first hybrid transmission–reflection optoacoustic ultrasound (TROPUS) small animal imaging platform that combines optoacoustic tomography with both reflection- and transmission-mode ultrasound computed tomography. The system features full-view cross-sectional tomographic imaging geometry for concomitant noninvasive mapping of the absorbed optical energy, acoustic reflectivity, speed of sound, and acoustic attenuation in whole live mice with submillimeter resolution and unrivaled image quality. Graphics-processing unit (GPU)-based algorithms employing spatial compounding and bent-ray-tracing iterative reconstruction were further developed to attain real-time rendering of ultrasound tomography images in the full-ring acquisition geometry. In vivo mouse imaging experiments revealed fine details on the organ parenchyma, vascularization, tissue reflectivity, density, and stiffness. We further used the speed of sound maps retrieved by the transmission ultrasound tomography to improve optoacoustic reconstructions via two-compartment modeling. The newly developed synergistic multimodal combination offers unmatched capabilities for imaging multiple tissue properties and biomarkers with high resolution, penetration, and contrast.

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Section: Introductionmentioning

confidence: 99%

Transmission–reflection optoacoustic ultrasound (TROPUS) computed tomography of small animals

et al. 2019

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“…In particular, strong light absorption by whole blood may impose additional visibility constraints (26) when imaging large blood vessels such as the carotid artery. The unique real-time volumetric imaging capacity of optoacoustics can potentially be integrated with US for a more comprehensive characterization of the carotid artery by means of a hybrid imaging probe, as was recently shown for the two-dimensional imaging case (27).…”

Section: Discussionmentioning

confidence: 91%

Real-time Volumetric Assessment of the Human Carotid Artery: Handheld Multispectral Optoacoustic Tomography

Ivanković¹,

Merčep²,

Schmedt³

et al. 2019

Radiology

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Radiology 2019; 00:1-7 • https://doi.org/10.1148/radiol.2019181325 • Content code:Background: Multispectral optical imaging has the capability of resolving hemoglobin, lipid, and water. Volumetric multispectral optoacoustic tomography (MSOT) is a hybrid imaging technique that provides a unique combination of functional and molecular contrast with real-time handheld imaging.Purpose: To investigate whether volumetric MSOT can provide real-time assessment of the anatomic and functional status of the human carotid artery bifurcation noninvasively. Materials and Methods:Imaging of healthy volunteers (n = 16) was performed with a custom-designed handheld volumetric MSOT scanner capable of high-spatial-resolution (approximately 200 µm) and real-time (10 volumes/sec) three-dimensional imaging, while further providing spectroscopic capacity through fast tuning of the excitation light wavelength. For comparison and anatomic cross-validation, volunteers were also scanned with clinical B-mode US.Results: Volumetric MSOT achieved real-time imaging and characterization of the entire carotid bifurcation area across three dimensions simultaneously captured in a single volumetric image frame. Analysis of the acquired data further showed that a higher contrast-to-noise ratio can be achieved for wavelengths corresponding to a high optical absorption of oxygenated hemoglobin. Conclusion:The human carotid artery was visualized by using handheld volumetric multispectral optoacoustic tomography. This imaging approach is less prone to motion artifacts than are the conventional clinical imaging methods, holding promise for providing additional image-based biomarkers for noninvasive label-free assessment of carotid artery disease.

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“…When it comes to applications where realtime imaging is needed, optoacoustic systems involving ultrasound arrays are the method of choice [[9], [10], [11], [12], [13], [14]]. Furthermore, wide-field illumination such as used in linear-array optoacoustics is advantageous with respect to the MPE (maximum permissible exposure).…”

Section: Introductionmentioning

confidence: 99%

Wave front analysis for enhanced time-domain beamforming of point-like targets in optoacoustic imaging using a linear array

Fournelle

Bost

2019

Photoacoustics

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Using linear array transducers in combination with state-of-the-art multichannel electronics allows to perform optoacoustic imaging with frame rates only limited by the laser pulse repetition frequency and the acoustic time of flight. However, characteristic image artefacts resulting from the limited view and a lower SNR when compared to systems based on single-element focused transducers represent a burden for the clinical acceptance of the technology. In this paper, we present a new method for the improvement of image quality based on the analysis of the signal amplitudes along summation curves during the delay-and-sum beamforming process (DAS). The algorithm compares amplitude distributions along wave fronts with theoretical patterns from optoacoustic point sources. The method was validated on simulated and experimental phantom as well as in-vivo data. An improvement of the lateral resolution by more than a factor of two when comparing conventional DAS and our approach could be shown (numeric and experimental phantom data). For instance, on experimental data from a wire phantom, a PSF in the range of 0.18–0.22 mm was obtained with our approach against 0.48 mm for standard DAS. Furthermore, the SNR of a subcutaneous vessel 2.5 mm below the skin surface was improved by about 30 dB when compared to standard DAS.

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Imaging of blood flow and oxygen state with a multi-segment optoacoustic ultrasound array

Cited by 52 publications

References 33 publications

Transmission–reflection optoacoustic ultrasound (TROPUS) computed tomography of small animals

Transmission–reflection optoacoustic ultrasound (TROPUS) computed tomography of small animals

Real-time Volumetric Assessment of the Human Carotid Artery: Handheld Multispectral Optoacoustic Tomography

Wave front analysis for enhanced time-domain beamforming of point-like targets in optoacoustic imaging using a linear array

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