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Spherical matrix arrays represent an advantageous tomographic detection geometry for non-invasive deep tissue mapping of vascular networks and oxygenation with volumetric optoacoustic tomography (VOT). Hybridization of VOT with ultrasound (US) imaging remains difficult with this configuration due to the relatively large inter-element pitch of spherical arrays. We suggest a new approach for combining VOT and US contrast-enhanced 3D imaging employing injection of clinically-approved microbubbles. Power Doppler (PD) and US localization imaging were enabled with a sparse US acquisition sequence and model-based inversion based on infimal convolution of total variation (ICTV) regularization. In vitro experiments in tissue-mimicking phantoms and in living mouse brain demonstrate the powerful capabilities of the new dual-mode imaging approach attaining 80 μm spatial resolution and a more than 10 dB signal to noise improvement with respect to a classical delay and sum beamformer. Microbubble localization and tracking allowed for flow velocity mapping up to 40 mm/s.
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http://dx.doi.org/10.1109/TMI.2021.3125398 | DOI Listing |
Photoacoustics
October 2025
Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 300044, Taiwan.
Spherical arrays are commonly used in volumetric optoacoustic tomography for optimal data acquisition. Yet, such a configuration poses challenges for integration with pulse-echo ultrasound used for image guidance, which relies on different signal acquisition and image formation strategies. A potential solution entails the incorporation of linear array segments into the spherical array to enable hybrid 3D optoacoustic and 2D ultrasound (OPUS) modes.
View Article and Find Full Text PDFLight Sci Appl
July 2025
Institute of Pharmacology and Toxicology and Institute for Biomedical Engineering, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
Owing to its unique ability to capture volumetric tomographic information with a single light flash, optoacoustic (OA) tomography has recently demonstrated ultrafast imaging speeds ultimately limited by the ultrasound time-of-flight. The method's scalability and the achievable spatial resolution are yet limited by the narrow bandwidth of piezo-composite arrays currently employed for OA signal detection. Here we report on the first implementation of high-density spherical array technology based on flexible polyvinylidene difluoride films featuring ultrawideband (0.
View Article and Find Full Text PDFAdv Mater
March 2025
Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
Despite the development of various medical imaging contrast agents, integrating contrast signal generation with therapeutic and microrobotic functions remains challenging without complicated fabrication processes. In this study, upconversion nanoparticle-covalent organic framework (UCNP-COF) core-shell sub-micron particles are developed that function as therapeutic microrobots trackable with multi-spectral optoacoustic tomography (MSOT) imaging and can be loaded with desired therapeutic molecular agents in a customizable manner. The mechanism of optoacoustic signal generation in UCNP-COF particles is attributed to the quenching of upconversion luminescence emitted by the UCNPs, which is absorbed by the encapsulating COF and subsequently converted into acoustic waves.
View Article and Find Full Text PDFIEEE Trans Med Imaging
April 2025
Given its direct relationship to tissue metabolism and various pathological processes, 3D mapping of blood oxygen saturation (sO2) is essential for advancing our knowledge on oxygen delivery to tissues and evaluating therapeutic efficacy. Optoacoustic microscopy has enabled label-free estimation of sO2 values by exploiting the spectrally distinctive absorption of hemoglobin in its oxygenated and deoxygenated forms. However, quantitative 3D mapping of sO2 distribution over large heterogenous tissue regions is commonly hindered due to the strong spatial and spectral variability of the excitation light fluence.
View Article and Find Full Text PDFAlzheimers Dement
February 2025
Institute for Biomedical Engineering and Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
Introduction: Transcranial pulse stimulation (TPS) is increasingly being investigated as a promising potential treatment for Alzheimer's disease (AD). Although the safety and preliminary clinical efficacy of TPS short pulses have been supported by neuropsychological scores in treated AD patients, its fundamental mechanisms are uncharted.
Methods: Herein, we used a multi-modal preclinical imaging platform combining real-time volumetric optoacoustic tomography, contrast-enhanced magnetic resonance imaging, and ex vivo immunofluorescence to comprehensively analyze structural and hemodynamic effects induced by TPS.