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Photoacoustics

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https://www.readbyqxmd.com/read/30003041/vascular-branching-point-counts-using-photoacoustic-imaging-in-the-superficial-layer-of-the-breast-a-potential-biomarker-for-breast-cancer
#1
Iku Yamaga, Nobuko Kawaguchi-Sakita, Yasufumi Asao, Yoshiaki Matsumoto, Aya Yoshikawa, Toshifumi Fukui, Masahiro Takada, Masako Kataoka, Masahiro Kawashima, Elham Fakhrejahani, Shotaro Kanao, Yoshie Nakayama, Mariko Tokiwa, Masae Torii, Takayuki Yagi, Takaki Sakurai, Hironori Haga, Kaori Togashi, Tsuyoshi Shiina, Masakazu Toi
This study aimed to identify the characteristics of the vascular network in the superficial subcutaneous layer of the breast and to analyze differences between breasts with cancer and contralateral unaffected breasts using vessel branching points (VBPs) detected by three-dimensional photoacoustic imaging with a hemispherical detector array. In 22 patients with unilateral breast cancer, the average VBP counts to a depth of 7 mm below the skin surface were significantly greater in breasts with cancer than in the contralateral unaffected breasts (p < 0...
September 2018: Photoacoustics
https://www.readbyqxmd.com/read/30003040/optoacoustic-signal-excitation-with-a-tone-burst-of-short-pulses
#2
X L Deán-Ben, D Razansky
No abstract text is available yet for this article.
September 2018: Photoacoustics
https://www.readbyqxmd.com/read/29988890/a-light-fluence-independent-method-for-the-quantitative-analysis-of-dynamic-contrast-enhanced-multispectral-optoacoustic-tomography-dce-msot
#3
Clinton W Hupple, Stefan Morscher, Neal C Burton, Mark D Pagel, Lacey R McNally, Julio Cárdenas-Rodríguez
MultiSpectral Optoacoustic Tomography (MSOT) is an emerging imaging technology that allows for data acquisition at high spatial and temporal resolution. These imaging characteristics are advantageous for Dynamic Contrast Enhanced (DCE) imaging that can assess the combination of vascular flow and permeability. However, the quantitative analysis of DCE MSOT data has not been possible due to complications caused by wavelength-dependent light attenuation and variability in light fluence at different anatomical locations...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29988848/photoacoustic-tomography-of-blood-oxygenation-a-mini-review
#4
REVIEW
Mucong Li, Yuqi Tang, Junjie Yao
Photoacoustic tomography (PAT) is a hybrid imaging modality that combines rich contrast of optical excitation and deep penetration of ultrasound detection. With its unique optical absorption contrast mechanism, PAT is inherently sensitive to the functional and molecular information of biological tissues, and thus has been widely used in preclinical and clinical studies. Among many functional capabilities of PAT, measuring blood oxygenation is arguably one of the most important applications, and has been widely performed in photoacoustic studies of brain functions, tumor hypoxia, wound healing, and cancer therapy...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29988835/assessing-nailfold-microvascular-structure-with-ultra-wideband-raster-scan-optoacoustic-mesoscopy
#5
J Aguirre, B Hindelang, Andrei Berezhnoi, U Darsow, F Lauffer, K Eyerich, T Biedermann, V Ntziachristos
Nailfold capillaroscopy, based on bright-field microscopy, is widely used to diagnose systemic sclerosis (SSc). However it cannot reveal information about venules and arterioles lying deep under the nailfold, nor can it provide detailed data about surface microvasculature when the skin around the nail is thick. These limitations reflect the fact that capillaroscopy is based on microscopy methods whose penetration depth is restricted to about 200 μm. We investigated whether ultra-wideband raster-scan optoacoustic mesoscopy (UWB-RSOM) can resolve small capillaries of the nailfold in healthy volunteers and compared the optoacoustic data to conventional capillaroscopy examinations...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29988801/imaging-of-blood-flow-and-oxygen-state-with-a-multi-segment-optoacoustic-ultrasound-array
#6
Elena Merčep, Xosé Luís Deán-Ben, Daniel Razansky
Changes in hemodynamic parameters are directly linked to biological function and physiological activity. Characterization of hemodynamics is commonly performed by Doppler ultrasound, which provides accurate measurements of blood flow velocity. Multi-spectral optoacoustic tomography is rapidly undergoing clinical translation fostered by its unique and complementary capacity for label-free mapping of the blood volume and the distribution of oxy- and deoxy-hemoglobin in blood. Here we report on a hybrid optoacoustic and ultrasound imaging approach that enables multi-modal imaging of blood flow and oxygen state using a multi-segment detector array...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29755937/rapid-scanning-wide-field-clutter-elimination-in-epi-optoacoustic-imaging-using-comb-lovit
#7
Tigran Petrosyan, Maria Theodorou, Jeff Bamber, Martin Frenz, Michael Jaeger
Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics and ultrasound receiver, yet clutter generated by optical absorption near the probe obscures deep OA sources. Localised vibration tagging (LOVIT) retrieves OA signal from images that are acquired with and without a preceding ultrasonic pushing beam: Radiation force leads to a phase shift of signals coming from the focal area resulting in their visibility in a difference image, whereas clutter from outside the pushing beam is eliminated...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29682448/cortical-hypoperfusion-and-reduced-cerebral-metabolic-rate-of-oxygen-in-the-arca%C3%AE-mouse-model-of-alzheimer-s-disease
#8
Ruiqing Ni, Markus Rudin, Jan Klohs
The effect of cerebral amyloidosis on cerebral hemodynamics was investigated with photoacoustic tomography (PAT) and magnetic resonance imaging (MRI). First, the sensitivity and robustness of PAT for deriving metrics of vascular and tissue oxygenation in the murine brain was assessed in wild-type mice with a hyperoxia-normoxia challenge. Secondly, cerebral oxygenation was assessed in young and aged arcAβ mice and wild-type controls with PAT, while cerebral blood flow (CBF) was determined by perfusion MRI. The investigations revealed that PAT can sensitively and robustly detect physiological changes in vascular and tissue oxygenation...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29511627/neonatal-brain-resting-state-functional-connectivity-imaging-modalities
#9
REVIEW
Ali-Reza Mohammadi-Nejad, Mahdi Mahmoudzadeh, Mahlegha S Hassanpour, Fabrice Wallois, Otto Muzik, Christos Papadelis, Anne Hansen, Hamid Soltanian-Zadeh, Juri Gelovani, Mohammadreza Nasiriavanaki
Infancy is the most critical period in human brain development. Studies demonstrate that subtle brain abnormalities during this state of life may greatly affect the developmental processes of the newborn infants. One of the rapidly developing methods for early characterization of abnormal brain development is functional connectivity of the brain at rest. While the majority of resting-state studies have been conducted using magnetic resonance imaging (MRI), there is clear evidence that resting-state functional connectivity (rs-FC) can also be evaluated using other imaging modalities...
June 2018: Photoacoustics
https://www.readbyqxmd.com/read/29707480/all-optical-extravascular-laser-ultrasound-and-photoacoustic-imaging-of-calcified-atherosclerotic-plaque-in-excised-carotid-artery
#10
Jami L Johnson, Mervyn Merrilees, Jeffrey Shragge, Kasper van Wijk
Photoacoustic (PA) imaging may be advantageous as a safe, non-invasive imaging modality to image the carotid artery. However, calcification that accompanies atherosclerotic plaque is difficult to detect with PA due to the non-distinct optical absorption spectrum of hydroxyapatite. We propose reflection-mode all-optical laser-ultrasound (LUS) imaging to obtain high-resolution, non-contact, non-ionizing images of the carotid artery wall and calcification. All-optical LUS allows for flexible acquisition geometry and user-dependent data acquisition for high repeatability...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29707479/towards-optimized-naphthalocyanines-as-sonochromes-for-photoacoustic-imaging-in-vivo
#11
Mitchell J Duffy, Oriol Planas, Andreas Faust, Thomas Vogl, Sven Hermann, Michael Schäfers, Santi Nonell, Cristian A Strassert
In this paper we establish a methodology to predict photoacoustic imaging capabilities from the structure of absorber molecules (sonochromes). The comparative in vitro and in vivo screening of naphthalocyanines and cyanine dyes has shown a substitution pattern dependent shift in photoacoustic excitation wavelength, with distal substitution producing the preferred maximum around 800 nm. Central ion change showed variable production of photoacoustic signals, as well as singlet oxygen photoproduction and fluorescence with the optimum for photoacoustic imaging being nickel(II)...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29707478/visualization-of-murine-lymph-vessels-using-photoacoustic-imaging-with-contrast-agents
#12
Ryo Nagaoka, Takuya Tabata, Shin Yoshizawa, Shin-Ichiro Umemura, Yoshifumi Saijo
Metastasis frequently occurs even in the early stage of breast cancer. This research studied the feasibility of using photoacoustic (PA) imaging for identifying metastasis in the lymph vessels of mice. The photoacoustic efficiency of various contrast agents was investigated, and the influence of scattered light was evaluated by using a lymph vessel phantom. The lymph vessels of mice were then visualized using the selected contrast agents: indocyanine green (ICG) and gold nanorods (AuNR). The attenuation of the PA imaging was -1...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29707477/multispectral-photoacoustic-microscopy-and-optical-coherence-tomography-using-a-single-supercontinuum-source
#13
M Bondu, M J Marques, P M Moselund, G Lall, A Bradu, A Podoleanu
We report on the use of a single supercontinuum (SC) source for multimodal imaging. The 2-octave bandwidth (475-2300 nm) makes the SC source suitable for optical coherence tomography (OCT) as well as for multispectral photoacoustic microscopy (MPAM). The IR band centered at 1310 nm is chosen for OCT to penetrate deeper into tissue with 8 mW average power on the sample. The 500-840 nm band is used for MPAM. The source has the ability to select the central wavelength as well as the spectral bandwidth. An energy of more than 35 nJ within a less than 50 nm bandwidth is achieved on the sample for wavelengths longer than 500 nm...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29387537/continuous-wave-laser-diodes-enable-fast-optoacoustic-imaging
#14
Antonios Stylogiannis, Ludwig Prade, Andreas Buehler, Juan Aguirre, George Sergiadis, Vasilis Ntziachristos
Pulsed laser diodes may offer a smaller, less expensive alternative to conventional optoacoustic laser sources; however they do not provide pulse rates faster than a few tens of kHz and emit at wavelengths only within the near-infrared region. We investigated whether continuous wave (CW) laser diodes, which are available in visible and near-infrared regions, can be good optoacoustic light sources when overdriven with a peak current >40-fold higher than the CW absolute maximum. We found that overdriven CW diodes provided ∼10 ns pulses of ∼200 nJ/pulse and repetition rates higher than 600 kHz without being damaged, outperforming many pulsed laser diodes...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29234601/the-characterization-of-an-economic-and-portable-led-based-photoacoustic-imaging-system-to-facilitate-molecular-imaging
#15
Ali Hariri, Jeanne Lemaster, Junxin Wang, AnanthaKrishnan S Jeevarathinam, Daniel L Chao, Jesse V Jokerst
Photoacoustic imaging (PAI) is a non-invasive, high-resolution hybrid imaging modality that combines optical excitation and ultrasound detection. PAI can image endogenous chromophores (melanin, hemoglobin, etc.) and exogenous contrast agents in different medical applications. However, most current equipment uses sophisticated and complicated OPO lasers with tuning and stability features inconsistent with broad clinical deployment. As the number of applications of PAI in medicine increases, there is an urgent need to make the imaging equipment more compact, portable, and affordable...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29201646/laser-scanning-laser-diode-photoacoustic-microscopy-system
#16
Mohsen Erfanzadeh, Patrick D Kumavor, Quing Zhu
The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens...
March 2018: Photoacoustics
https://www.readbyqxmd.com/read/29034169/fluence-compensation-in-raster-scan-optoacoustic-angiography
#17
Mikhail Kirillin, Valeriya Perekatova, Ilya Turchin, Pavel Subochev
Modern optical imaging techniques demonstrate significant potential for high resolution in vivo angiography. Optoacoustic angiography benefits from higher imaging depth as compared to pure optical modalities. However, strong attenuation of optoacoustic signal with depth provides serious challenges for adequate 3D vessel net mapping, and proper compensation for fluence distribution within biotissues is required. We report on the novel approach allowing to estimate effective in-depth fluence profiles for optoacoustic systems...
December 2017: Photoacoustics
https://www.readbyqxmd.com/read/29034168/quantitative-comparison-of-pzt-and-cmut-probes-for-photoacoustic-imaging-experimental-validation
#18
Maëva Vallet, François Varray, Jérôme Boutet, Jean-Marc Dinten, Giosuè Caliano, Alessandro Stuart Savoia, Didier Vray
Photoacoustic (PA) signals are short ultrasound (US) pulses typically characterized by a single-cycle shape, often referred to as N-shape. The spectral content of such wideband signals ranges from a few hundred kilohertz to several tens of megahertz. Typical reception frequency responses of classical piezoelectric US imaging transducers, based on PZT technology, are not sufficiently broadband to fully preserve the entire information contained in PA signals, which are then filtered, thus limiting PA imaging performance...
December 2017: Photoacoustics
https://www.readbyqxmd.com/read/29034167/characterization-of-lens-based-photoacoustic-imaging-system
#19
Kalloor Joseph Francis, Bhargava Chinni, Sumohana S Channappayya, Rajalakshmi Pachamuthu, Vikram S Dogra, Navalgund Rao
Some of the challenges in translating photoacoustic (PA) imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF)...
December 2017: Photoacoustics
https://www.readbyqxmd.com/read/28971019/piezoelectric-line-detector-array-for-photoacoustic-tomography
#20
Guenther Paltauf, Petra Hartmair, Georgi Kovachev, Robert Nuster
Photoacoustic tomography relies on a dense coverage of the surface surrounding the imaged object with ultrasound sensors in order to enable an accurate reconstruction. A curved arrangement of integrating line sensors is proposed that is able to acquire data for a linear projection image of the absorbed energy density distribution in the object. Upon rotation of the object relative to the array, three-dimensional (3D) images can be obtained. The proposed design is based on the cost-effective piezoelectric polymer film technology with 64 line shaped sensors arranged on a half-cylindrical surface...
December 2017: Photoacoustics
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