Soft ultrasound priors in optoacoustic reconstruction: Improving clinical vascular imaging

Yang, Hong; Jüstel, Dominik; Prakash, Jaya; Karlas, Angelos; Helfen, Anne; Masthoff, Max; Wildgruber, Moritz; Ntziachristos, Vasilis

doi:10.1016/j.pacs.2020.100172

Cited by 32 publications

(22 citation statements)

References 55 publications

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“…For quantitative analysis, the mean intensity ratios between the ROI and the background ROI were calculated to allow for data comparison of different patients, as reported earlier [ 13 ]. As such, the effects of imaging depth and light fluence are minimized.…”

Section: Methodsmentioning

confidence: 99%

“…Ivankovic et al showed visualization of the carotid artery with high sensitivity and spatial resolution in vivo using optoacoustic imaging [ 8 ]. More recently, MSOT was used for carotid plaque visualization [ 13 ]. Here, we study if an intravenous injection of bevacizumab-800CW, a near-infrared fluorescent tracer that has been used in pilot studies in surgical oncology, is safe in patients undergoing CEA, a vulnerable patient population with multiple risk factors of cardiovascular disease [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

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VEGF-Targeted Multispectral Optoacoustic Tomography and Fluorescence Molecular Imaging in Human Carotid Atherosclerotic Plaques

et al. 2021

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Vulnerable atherosclerotic carotid plaques are prone to rupture, resulting in ischemic strokes. In contrast to radiological imaging techniques, molecular imaging techniques have the potential to assess plaque vulnerability by visualizing diseases-specific biomarkers. A risk factor for rupture is intra-plaque neovascularization, which is characterized by overexpression of vascular endothelial growth factor-A (VEGF-A). Here, we study if administration of bevacizumab-800CW, a near-infrared tracer targeting VEGF-A, is safe and if molecular assessment of atherosclerotic carotid plaques in vivo is possible using multispectral optoacoustic tomography (MSOT). Healthy volunteers and patients with symptomatic carotid artery stenosis scheduled for carotid artery endarterectomy were imaged with MSOT. Secondly, patients were imaged two days after intravenous administration of 4.5 bevacizumab-800CW. Ex vivo fluorescence molecular imaging of the surgically removed plaque specimen was performed and correlated with histopathology. In this first-in-human MSOT and fluorescence molecular imaging study, we show that administration of 4.5 mg bevacizumab-800CW appeared to be safe in five patients and accumulated in the carotid atherosclerotic plaque. Although we could visualize the carotid bifurcation area in all subjects using MSOT, bevacizumab-800CW-resolved signal could not be detected with MSOT in the patients. Future studies should evaluate tracer safety, higher doses of bevacizumab-800CW or develop dedicated contrast agents for carotid atherosclerotic plaque assessment using MSOT.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

VEGF-Targeted Multispectral Optoacoustic Tomography and Fluorescence Molecular Imaging in Human Carotid Atherosclerotic Plaques

et al. 2021

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“…This energy deposition results in a small increase in temperature which produces a thermoelastic expansion and a local pressure increase, which in turn induces a measurable ultrasonic pressure wave [ 13 ]. This process is known as the radio-induced thermoacoustic effect, and it is also used for photoacoustic and optoacoustic imaging [ [38] , [39] , [40] , [41] , [42] ]. Under thermal and stress confinement conditions [ 29 , 43 ], the initial pressure distribution can be calculated from the dose distribution as [ 29 , 43 ]:

where

is the Grüneisen coefficient, a material-specific dimensionless parameter that indicates the conversion efficiency between the absorbed heat energy and the induced pressure (

, where

is the speed of sound,

is the isobaric volume expansion coefficient and

is the specific heat capacity) [ 43 ];

is the dose distribution and

is the medium mass density.…”

Section: Dictionary-based Protoacoustic Dose Reconstructionmentioning

confidence: 99%

Dictionary-based protoacoustic dose map imaging for proton range verification

Freijo¹,

Herraiz

Sánchez-Parcerisa

et al. 2021

Photoacoustics

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“…We selected a uniform SoS just below that of water, whereby the highest resolution and contrast reconstruction is obtained. For higher image quality and more precise quantitative measurements, the acoustic velocity mismatch will have to be taken into account in a priori reconstructions using SoS and structural information (note S5) (52)(53)(54). RThAM images are reconstructed based on filtered back projection algorithm and showed using MIP of the reconstructed signals.…”

Section: Signal Processing and Image Formationmentioning

confidence: 99%

Noninvasive visualization of electrical conductivity in tissues at the micrometer scale

et al. 2021

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Despite its importance in regulating cellular or tissue function, electrical conductivity can only be visualized in tissue indirectly as voltage potentials using fluorescent techniques, or directly with radio waves. These either requires invasive procedures like genetic modification or suffers from limited resolution. Here, we introduce radio-frequency thermoacoustic mesoscopy (RThAM) for the noninvasive imaging of conductivity by exploiting the direct absorption of near-field ultrashort radio-frequency pulses to stimulate the emission of broadband ultrasound waves. Detection of ultrasound rather than radio waves enables micrometer-scale resolutions, over several millimeters of tissue depth. We confirm an imaging resolution of <30 μm in phantoms and demonstrate microscopic imaging of conductivity correlating to physical structures in 1- and 512-cell zebrafish embryos, as well as larvae. These results support RThAM as a promising method for high-resolution, label-free assessment of conductivity in tissues.

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Soft ultrasound priors in optoacoustic reconstruction: Improving clinical vascular imaging

Cited by 32 publications

References 55 publications

VEGF-Targeted Multispectral Optoacoustic Tomography and Fluorescence Molecular Imaging in Human Carotid Atherosclerotic Plaques

VEGF-Targeted Multispectral Optoacoustic Tomography and Fluorescence Molecular Imaging in Human Carotid Atherosclerotic Plaques

Dictionary-based protoacoustic dose map imaging for proton range verification

Noninvasive visualization of electrical conductivity in tissues at the micrometer scale

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