A5062776420- Photoacoustic and Ultrasonic Imaging
- Optical Imaging and Spectroscopy Techniques
- Optical Coherence Tomography Applications
- Thermography and Photoacoustic Techniques
- Nanoplatforms for cancer theranostics
- Advanced Fiber Optic Sensors
- Ultrasonics and Acoustic Wave Propagation
- Coronary Interventions and Diagnostics
- Advanced Fluorescence Microscopy Techniques
- Cardiac Imaging and Diagnostics
- Advanced Biosensing Techniques and Applications
- Hemodynamic Monitoring and Therapy
- Ultrasound and Hyperthermia Applications
- Cerebrovascular and Carotid Artery Diseases
Massachusetts General Hospital
2021-2023
Harvard University
2022
Helmholtz Zentrum München
2014-2021
Technical University of Munich
2014-2021
Institute of Biological and Medical Imaging
2016-2021
Originally developed for diagnostic ultrasound imaging, piezoelectric transducers are the most widespread technology employed in optoacoustic (photoacoustic) signal detection. However, detection requirements of sensing and imaging differ from those conventional ultrasonography lead to specifications not sufficiently addressed by detectors. Consequently, interest has shifted utilizing entirely optical methods measuring waves. All-optical sound detectors yield a higher signal-to-noise ratio...
The addition of optoacoustic sensing to optical microscopy may supplement fluorescence contrast with label-free measurements absorption, enhancing biological observation. However, the physical dimensions many systems have restricted implementation hybrid and (O2A) imaging thin samples in transmission mode or ex-vivo investigations. Here we describe a miniaturized sensor, based on π-phase-shifted fiber Bragg grating embedded an acoustic cavity, which is virtually invisible path can be...
Optical and optoacoustic (photoacoustic) microscopy have been recently joined in hybrid implementations that resolve extended tissue contrast compared to each modality alone. Nevertheless, the application of technique is limited by requirement combine an optical objective with ultrasound detection collecting signal from same micro-volume. We present all-optical microscope based on a pi-phase-shifted fiber Bragg grating (π-FBG) coherence-restored pulsed interferometry (CRPI) used as...
A critical link exists between pathological changes of cerebral vasculature and diseases affecting brain function. Microscopic techniques have played an indispensable role in the study neurovascular anatomy functions. Yet, investigations are often hindered by suboptimal trade‐offs spatiotemporal resolution, field‐of‐view (FOV) type contrast offered existing optical microscopy techniques. We present a hybrid dual‐wavelength optoacoustic (OA) biomicroscope capable rapid transcranial...
(i) to evaluate a novel hybrid near-infrared fluorescence-intravascular ultrasound (NIRF-IVUS) system in coronary and peripheral swine arteries vivo; (ii) assess simultaneous quantitative biological morphological aspects of arterial disease.Two 9F/15MHz 4.5F/40MHz fluorescence (NIRF)-IVUS catheters were engineered enable accurate co-registrtation readings simultaneously vivo. A correction algorithm utilizing IVUS information was developed account for the distance-related attenuation due...
We propose the implementation of hybrid optical and acoustic resolution optoacoustic endoscopy. Laser light is transmitted to tissue by two types illumination for achieving imaging. A 20 MHz ultrasound detector used recording signals. The endoscopy probe attains a 3.6 mm diameter fully encapsulated into catheter system. validate imaging performance endoscope on phantoms ex vivo, discuss necessity extended depth range achieved.
In this study a theoretical framework for calculating the acoustic response of optical fiber-based ultrasound sensors is presented. The evaluated fibers with several layers coating assuming harmonic point source arbitrary position and frequency. First, fiber acoustically modeled by layered cylinder on which spherical waves are impinged. scattering calculated analytically used to find normal components strains axis. Then, strain-optic model calculate phase shift experienced guided mode in...
Abstract The recent development of ultrasound sensing using the silicon‐photonics platform has enabled super‐resolution optoacoustic imaging not possible by piezoelectric technology or polymeric optical microresonators. silicon waveguide etalon detector (SWED) design exploits sub‐micrometer light confinement in cross‐section a strip to achieve sensor aperture which is 13‐fold 30‐fold smaller than cutoff wavelength sensor. While its performance near‐field scanning been previously studied,...
Coronary artery disease (CAD) remains a leading cause of mortality and warrants new imaging approaches to better guide clinical care. We report on miniaturized, hybrid intravascular catheter system for comprehensive coronary in vivo. Our exhibits total diameter 1.0 mm (3.0 French), equivalent standalone ultrasound (IVUS) catheters but enables simultaneous near-infrared fluorescence (NIRF) IVUS molecular-structural imaging. demonstrate NIRF-IVUS vitro stents using NIR fluorophores, compare...
SignificanceIntravascular near-infrared fluorescence (NIRF) imaging aims to improve the inspection of vascular pathology using fluorescent agents with specificity disease biomarkers. The method has been developed operate in tandem an anatomical modality, such as intravascular ultrasound (IVUS), and complements readings pathophysiological contrast, enhancing information obtained from hybrid examination.AimHowever, attenuation NIRF signals by blood challenges quantification. We propose a new...
We present an optoacoustic (photoacoustic) microscopy (OAM) imaging system that uses a pi-shifted Fiber Bragg Grating (pi-FBG) as ultrasound (US) sensor. The sensor has ultra-small footprint and hence allows for the detection of signals in close proximity to their origin. interrogation pi-FBG is performed by broadband pulsed laser, enabling high sensitivity well elimination ambient noise. characterize terms axial lateral resolution its bandwidth find performance comparable US sensors are...
A theoretical framework is presented for calculating the opto-acoustic response of optical fiber ultrasound sensors with several layers coating. harmonic point source generating a spherical wavefront arbitrary position and frequency assumed. The acoustically modeled by layered cylinder on which waves are scattered. principle strains axis calculated from scattering acoustic used in strain-optic model to calculate phase shift guided modes. results compared experimental data obtained sensing...
A theoretical framework is presented for calculating the opto-acoustic response of optical fiber ultrasound sensors with several layers coating. harmonic point source generating a spherical wavefront arbitrary position and frequency assumed. The acoustically modeled by layered cylinder on which waves are scattered. principle strains axis calculated from scattering acoustic used in strain-optic model to calculate phase shift guided modes. results compared experimental data obtained sensing...
A hybrid optical and acoustic resolution optoacoustic endoscopy is proposed. Laser light transmitted to tissue by two types of illumination for imaging respectively. An unfocused ultrasound detector used recording signals. The probe attains 3.6 mm diameter fully encapsulated into a catheter system. We examine the performance endoscope with phantoms sample, which shows that can obtain in superficial microscopic ultrasonic tomography reconstruction when at greater depths.
Optoacoustic microscopy (OAM) has enabled high-resolution, label-free imaging of tissues at depths not achievable with purely optical microscopy. However, widespread implementation OAM into existing epi-illumination setups is often constrained by the performance and size commonly used piezoelectric ultrasound detectors. In this work, we introduce a novel acoustic detector based on π-phase-shifted fiber Bragg grating (π-FBG) interferometer embedded inside an ellipsoidal cavity. The cavity...
To enable quantitative molecular and morphological readings in vivo, a near-infrared fluorescence (NIRF)-IVUS catheter novel correction algorithm were engineered. Hybrid imaging was validated atherosclerotic rabbit model vivo.
Acoustic imaging modalities such as multispectral optoacoustic tomography (MSOT) have recently matured to a point which allows retrieval of anatomical, molecular and dynamic information with resolutions several tens microns These advancements are going hand in the continuous development ultrasound detectors. Yet, traditional piezoelectric transducers distinct disadvantage: detector size is proportional its sensitivity. This limits miniaturization prevents point-like detectors well subsequent...