Photons Plus Ultrasound: Imaging and Sensing 2019最新文献

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Simultaneous photoacoustic imaging and white light video endoscopy for guiding laparoscopic surgery (Conference Presentation) 同时光声成像和白光视频内窥镜用于指导腹腔镜手术(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2507548
Rehman Ansari, N. Huynh, E. Zhang, A. Desjardins, P. Beard
{"title":"Simultaneous photoacoustic imaging and white light video endoscopy for guiding laparoscopic surgery (Conference Presentation)","authors":"Rehman Ansari, N. Huynh, E. Zhang, A. Desjardins, P. Beard","doi":"10.1117/12.2507548","DOIUrl":"https://doi.org/10.1117/12.2507548","url":null,"abstract":"White light endoscopy is widely used both as a diagnostic tool for the assessment of abdominal cancers and to help guide their surgical excision using minimally invasive procedures. However, the information it provides is limited to visual inspection of the tissue surface. Endoscopic ultrasonography provides depth-resolved morphological images but exhibits poor label-free microvascular contrast thus limiting its ability to identify and delineate deep seated tumours. These drawbacks can potentially be addressed by using a laparoscopic probe that provides co-registered photoacoustic (PA) and white light endoscopy images. With the help of PA contrast, the probe can visualise depth-resolved microvasculature and thus offers the prospect of more sensitive detection of tumours based on abnormal vascular anatomy and function. However, it is challenging to implement such a probe using conventional piezoelectric transducers. Their opaque nature makes it difficult to achieve forward-viewing capability in a small footprint as required for laparoscopic use as well as incorporate videoscopy. Furthermore, achieving sufficiently widebandwidth (tens of MHz) and λ/2 spatial sampling as required for high resolution endoscopic PA imaging present further challenges. \u0000To address these challenges, we present a rigid miniature forward-viewing endoscope that is based on a transparent optical ultrasound sensor which offers a wideband response up to 50 MHz with sub-100 µm spatial sampling. The probe is designed for laparoscopic use. It is 260 mm long and 9 mm in outer diameter to permit insertion via a standard 12 mm abdominal trochar and comprises a lens relay system with a high-finesse FP ultrasound sensor at its distal end. The sensor is designed to operate in the 1500 – 1600 nm spectral range with high transmission in the visible to near-infrared region (550 – 1200 nm). The latter not only enables delivery of near-infrared pulsed excitation light through the sensor to acquire PA images but also transmission of visible CW light for simultaneous acquisition of wide-field video images at the probe tip. A MEMS scanning mirror located at the proximal end of the probe scans the FP sensor via the optical relay with 8 focused beams from a CW tunable laser source (1550 nm centre wavelength) to map the generated photoacoustic waves. High-resolution 3D tomographic images are reconstructed using a time reversal algorithm and fused with the white light video images. \u0000The probe has 8 mm lateral field-of-view and the NEP is 200 Pa over 20 MHz bandwidth. The lateral spatial resolution is 52 µm at a depth of 1 mm decreasing to 110µm at a depth of 7 mm. The axial resolution is 29 µm over this depth range. To demonstrate potential clinical applicability, the probe was evaluated in an in vivo sheep study and shown to provide excellent high resolution 3D images of vascular structures in the liver, kidney and placentomes. This novel forward-viewing PAE probe could provide new opportunities ","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121074857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Quantitative depth selective measurements of flow using acousto-optic diffuse correlation spectroscopy (Conference Presentation) 利用声光漫射相关光谱定量深度选择测量流量(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2510349
Mitchell B. Robinson, S. Carp, D. Boas, M. Franceschini
{"title":"Quantitative depth selective measurements of flow using acousto-optic diffuse correlation spectroscopy (Conference Presentation)","authors":"Mitchell B. Robinson, S. Carp, D. Boas, M. Franceschini","doi":"10.1117/12.2510349","DOIUrl":"https://doi.org/10.1117/12.2510349","url":null,"abstract":"Diffuse correlation spectroscopy (DCS) is an emerging technology that allows for the quantitative estimation of blood flow in tissue. By monitoring the autocorrelation of the time course of light speckle intensity, information about the motion of scattering particles, mostly red blood cells in the microvasculature of biological tissues, can be determined. The speckle fluctuations are due to motion of scatters along the entire path length of the photon from the source to the detector, which makes the determination of the location of the motion a difficult task. Multi-distance and tomographic methods have been employed to measure decorrelation times at different source detector separations, which helps to separate superficial blood flow from blood flow deeper in the tissue. DCS in the time-domain (TD-DCS) is being evaluated as a method to increase depth sensitivity by considering only the late arriving photons. Depth resolved quantification of blood flow is especially important when blood flow measurements of the brain are desired, as the superficial blood flow of the scalp is a known contaminant to the cortical signal. Recent demonstrations by other groups have shown the utility of ultrasound tagging of light to be an effective method to discriminate flow at different depths.1 Here we utilize ultrasound pulses to modulate the motion of particles at specific depths, which is dependent upon the time-of-flight of the ultrasound pulse. By analyzing the autocorrelation of the speckle intensity at different delay periods after the pulse, quantitative, depth specific information about the flow can be determined. \u0000\u0000References:\u00001.\tTsalach, A. et al. Depth selective acousto-optic flow measurement. Biomed. Opt. Express 6, 4871–86 (2015).","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115083040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A novel light emitting diodes based photoacoustic evaluation method for port wine stain and its clinical trial (Conference Presentation) 一种新的基于发光二极管的光声评价方法及其临床试验(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2507874
Haonan Zhang, Jingyue Pan, Long Wen, Shuzhan Shen, Yunfeng Zhang, Peiru Wang, Qian Cheng, Xiuli Wang, Xueding Wang
{"title":"A novel light emitting diodes based photoacoustic evaluation method for port wine stain and its clinical trial (Conference Presentation)","authors":"Haonan Zhang, Jingyue Pan, Long Wen, Shuzhan Shen, Yunfeng Zhang, Peiru Wang, Qian Cheng, Xiuli Wang, Xueding Wang","doi":"10.1117/12.2507874","DOIUrl":"https://doi.org/10.1117/12.2507874","url":null,"abstract":"Port-wine stain (PWS) is a discoloration of human skin caused by a vascular anomaly (i.e., capillary malformation in the skin). In the past years, several techniques have been developed for characterization and treatment evaluation of PWS. However, each of them has some limitations. Optical methods working in the ballistic regime, such as dermoscopy and VISIA, do not have sufficient penetration to cover the entire scale of PWS. High frequency ultrasound, although with better imaging depth, does not offer sufficient contrast to differentiate PWS and normal skin tissue. Therefore, current endpoint clinical assessment for PWS still relies on physicians’ subjective judgement. In this study, photoacoustic (PA) imaging utilizing light emitting diodes (LED) as the light source was adapted to the evaluation of PWS and response to photodynamic therapy (PDT). PA images as well as US images of the targeted skin area before and at different time points after the treatment were acquired. The imaging results from adults and children were also compared. The imaging findings demonstrate that the PWS levels of adult patients are significantly higher than children (p<0.01), which fits well with the knowledge that the vessel malefaction degree develops with patients’ age. The 2-month follow-up study on four children shows that the average PWS level reduced for 33.60%onstrat (p<0.01) as a result of 3-4 times of PDT treatment. This initial clinical trial on patients suggests PA imaging holds potential for quantitative assessment of PWS in clinical settings.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122290518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Real-time 2D all-optical ultrasound imaging with a dynamically reconfigurable imaging aperture (Conference Presentation) 具有动态可重构成像孔径的实时二维全光超声成像(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2507792
E. Alles, A. Desjardins
{"title":"Real-time 2D all-optical ultrasound imaging with a dynamically reconfigurable imaging aperture (Conference Presentation)","authors":"E. Alles, A. Desjardins","doi":"10.1117/12.2507792","DOIUrl":"https://doi.org/10.1117/12.2507792","url":null,"abstract":"All-optical ultrasound imaging uses optical generation and detection of ultrasound to acquire pulse-echo images. Recent advances have resulted in efficient optical ultrasound sources, emitting pressures and bandwidths rivalling those generated by conventional electronic transducers. Two-dimensional imaging of biological tissues was achieved using a fibre-optic Fabry-Perot cavity and a nanocomposite generator membrane in which ultrasound was generated photoacoustically. Using scanning mirrors, excitation light was steered to consecutive locations, thus synthesising an acoustic source aperture with a geometry that could be arbitrarily and dynamically reconfigured. This unique capability of implementing different geometries on the same hardware allows for a direct comparison of the image quality obtained with different aperture geometries, which is difficult to achieve using conventional electronic transducers. Here we explore how the source aperture geometry affects the image quality through a set of numerical simulations and experiments. First, we determined that the image artefacts and corresponding contrast level depend strongly on the total number of A-scans (increasing from 200 to 1800 A-scans improved the contrast from 30 to 50 dB), irrespective of the number and locations of the detectors. Second, we demonstrated how parametric optimisation of the spatial optical ultrasound source distribution allowed for local (within a user-defined region of interest) or global image optimisation achieving an additional reduction in artefact level of up to 8 dB. Finally, we demonstrated video-rate, real-time 2D image acquisition using optimised source aperture geometries.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122361866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cortex-wide multi-parametric photoacoustic microscopy (Conference Presentation) 全皮质多参数光声显微镜(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2509743
Zhiqiang Xu, Yiming Wang, Naidi Sun, Ruimin Chen, Qifa Zhou, Song Hu
{"title":"Cortex-wide multi-parametric photoacoustic microscopy (Conference Presentation)","authors":"Zhiqiang Xu, Yiming Wang, Naidi Sun, Ruimin Chen, Qifa Zhou, Song Hu","doi":"10.1117/12.2509743","DOIUrl":"https://doi.org/10.1117/12.2509743","url":null,"abstract":"Multi-parametric photoacoustic microscopy (PAM) is uniquely capable of quantifying the cerebral hemodynamics and oxygen metabolism at the microscopic level. However, the limited depth of focus of conventional PAM is insufficient to encompass the depth variation of the mouse brain when imaging a large area. For instance, the surface contour of the mouse cortex is dome-shaped and spans several hundred microns along the depth direction. When out of focus, the resolution and sensitivity of PAM quickly degrades. Moreover, quantitative measurements (e.g., blood oxygenation and flow) are no longer accurate with the compromised resolution and sensitivity. Here, we report automated contour-scan multi-parametric PAM, which enables simultaneous imaging of blood perfusion, oxygenation and flow with high resolution and sensitivity over the entire mouse cortex. Different from the traditional contour-scan method that requires three steps (pre-scan, off-line calculation of the contour map, and contour scan), our technique can perform high-resolution wide-field contour scan without the first two steps, thereby significantly reducing the acquisition time. We first tested the feasibility of this technique by imaging a plastic ball coated with black ink. Then, we quantitatively analyzed the influence of out-of-focus on the measurement of blood flow in a vessel-mimicking phantom. Finally, we demonstrated cortex-wide multi-parametric PAM in the live mouse brain with high resolution and sensitivity.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125184173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The interaction mechanism of methylene blue and heparin in phosphate buffered saline (Conference Presentation) 亚甲基蓝与肝素在磷酸盐缓冲盐水中的相互作用机制(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2508130
Junxin Wang, A. Jeevarathinam, K. Humphries, Bill R. Miller, J. Jokerst
{"title":"The interaction mechanism of methylene blue and heparin in phosphate buffered saline (Conference Presentation)","authors":"Junxin Wang, A. Jeevarathinam, K. Humphries, Bill R. Miller, J. Jokerst","doi":"10.1117/12.2508130","DOIUrl":"https://doi.org/10.1117/12.2508130","url":null,"abstract":"We recently reported a real-time method to measure heparin in blood based on photoacoustic (PA) signal from methylene blue (MB). The PA enhancement was surprisingly accompanied by a decrease in absorbance. Here, we describe a mechanistic study of the MB-heparin binding in water and phosphate buffered saline. The addition of 0.79 mg/mL heparin decreased the nuclear magnetic resonance (NMR) magnitude of 0.90 mg/mL MB by 63% with a 0.25 ppm downshift—this indicated formation of MB aggregates due to π-π staking of MB. We also observed nanoscale MB/heparin aggregates under transmission electron microscopy (TEM). Spectroscopic analysis of the isolated aggregates found that the percentage of MB inside the MB-heparin aggregate increased from 3.6% to 82.5% when heparin concentration was increased from 0.16 mg/mL to 0.79 mg/mL. Meanwhile, the photoacoustic intensity increased 25-fold. The signal increase was largely due to the aggregates rather than free MB in the solution. These trends suggested that the MB-heparin aggregation was responsible for the PA enhancement likely due to the decreased degrees of freedom for MB. Molecular dynamics simulations revealed MB dimer formation on heparin and indicated that electrostatic binding occurred between the central thiazine ring of MB and the sulfates and glucosamines in heparin via electrostatic interaction. These findings elucidate the binding process of MB and heparin and provide strategies for immobilizing MB-like molecules on implantable devices for intravascular heparin sensing.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"69 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128779679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Fiber optoacoustic converter for spatially confined ultrasound neuromodulation (Conference Presentation) 用于空间受限超声神经调节的光纤光声转换器(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2508752
Ying Jiang, L. Lan, Hua-an Tseng, Chen Yang, H. Man, Xue Han, Ji‐Xin Cheng
{"title":"Fiber optoacoustic converter for spatially confined ultrasound neuromodulation (Conference Presentation)","authors":"Ying Jiang, L. Lan, Hua-an Tseng, Chen Yang, H. Man, Xue Han, Ji‐Xin Cheng","doi":"10.1117/12.2508752","DOIUrl":"https://doi.org/10.1117/12.2508752","url":null,"abstract":"Generation of ultrasound using the optoacoustic effect has received increasing attention in the field of imaging and translational medicine. However, none of the current optoacoustic converters has been used for neural modulation. Here, we developed a miniaturized Fiber-Optoacoustic Converter (FOC), which has a diameter of 600 μm, and can convert nano-second laser pulses into acoustic waves through the optoacoustic effect. The ball shaped FOC is composed of one ZnO /epoxy based diffusion layer and two graphite/epoxy based absorption layer. The radiofrequency spectrum of the generated US frequency ranges from 0.1-5 MHz, with multiple frequencies peaks at 0.5, 1 and 3MHz. Compared to traditional ultrasound transducers, the FOC system has the advantages of miniaturized size, superior spatial resolution, and produces omnidirectional propagating acoustic wave. Using this FOC system, we show that ultrasound can directly activate individual cortical neuron in vitro with a radius of 500 μm around the FOC tip, and generate intracellular Ca2+ transient without neural damage. Neural activation is the consequence of mechanical disturbance of neuronal membrane, rather than direct laser or photothermal stimulation. Finally, we combine FOC neural modulation with electrophysiology, and achieve direct and spatially confined neural stimulation in vivo. The FOC system opens new possibilities to use optoacoustic effect as a new method for precise neural modulation.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114443040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Molecular imaging of oxidative stress sensing using LED-based photoacoustic imaging (Conference Presentation) 基于led光声成像的氧化应激传感分子成像(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2509204
A. Hariri, A. Jeevarathinam, E. Zhao, J. Jokerst
{"title":"Molecular imaging of oxidative stress sensing using LED-based photoacoustic imaging \u0000 (Conference Presentation)","authors":"A. Hariri, A. Jeevarathinam, E. Zhao, J. Jokerst","doi":"10.1117/12.2509204","DOIUrl":"https://doi.org/10.1117/12.2509204","url":null,"abstract":"We developed and designed a near-infrared (NIR) absorbing diboronate xanthene dye ((E)-1,3,3-trimethyl-2-(2-(6-((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)-2,3-dihydro-1H-xanthen-4-yl)vinyl)-3H-indol-1-ium) for photoacoustic imaging that is sensitive to reactive oxygen and nitrogen species (RONS). We initially used the probe with an OPO-based laser but found that the photoacoustic intensity degrades by 2.6-fold within 3150 laser pulses. Therefore, we adopted the probe to a LED-based excitation source (The average and standard deviation of photoacoustic intensity in presence of 3150 LED pulses is 118.08 and 1.67 (1.4% variation) respectively) and found that hydrogen peroxide (H2O2), superoxide radical (O2˙ −), and peroxynitrite (ONOO−) produce absorption at 700 nm, which was used for photoacoustic excitation. We observed a photoacoustic intensity increase of 2.1-, 1.9-, and 1.75-fold with addition of ONOO−, O2˙ −, and H2O2, (50 ), respectively. The dye is not sensitive to OCl − and ˙OH. At vascular compartment, formation of ONOO− is based on the reaction of nitric oxide (˙NO) with superoxide radical (O2˙ −) and formed ONOO− xidize plasmatic components as well as reaction with intracellular. We then tested the photoacoustic response of various concentrations of ONOO− (25, 50, 125, 185, 250, 375, and 500) in whole human plasma and blood. Concentrations of 50 ONOO− were also easily detectable with this probe. Finally, we examined the capability of new molecular probe for detection of endogenous RONS via SKOV3 (ovarian cancer) cell media. The RONS from these cells activated the probe but media treated with N-acetylcystein (NAC) (RONS scavenger) did not. In pre-incubated cells with NAC, we observed 2.5-fold decrease in photoacoustic intensity versus untreated cells.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126271624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Super-resolution photoacoustic imaging with a sparse array (Conference Presentation) 稀疏阵列的超分辨率光声成像(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2507468
Sergey Vilov, B. Arnal, Eliel Hojman, Oren Solomon, Yonina C. Eldar, E. Bossy, O. Katz
{"title":"Super-resolution photoacoustic imaging with a sparse array (Conference Presentation)","authors":"Sergey Vilov, B. Arnal, Eliel Hojman, Oren Solomon, Yonina C. Eldar, E. Bossy, O. Katz","doi":"10.1117/12.2507468","DOIUrl":"https://doi.org/10.1117/12.2507468","url":null,"abstract":"It has been shown that sub-diffraction structures can be resolved in acoustic resolution photoacoustic imaging thanks to norm-based iterative reconstruction algorithms exploiting prior knowledge of the point spread function (PSF) of the imaging system. Here, we demonstrate that super-resolution is still achievable when the receiving ultrasonic probe has much fewer elements than used conventionally (8 against 128). To this end, a proof-of-concept experiment was conducted. A microfluidic circuit containing five parallel microchannels (channel’s width 40μm, center-to center distance 180μm) filled with dye was exposed to 5ns laser pulses (=532nm, fluence=3.0mJ/cm2, PRF=100Hz). Photoacoustic signals generated by the sample were captured by a linear ultrasonic array (128 elements, pitch=0.1mm, fc=15MHz) connected to an acquisition device. The forward problem is modelled in a matrix form Y=AX, where Y are the measured photoacoustic signals and X is the object to reconstruct. The matrix A contained the PSFs at all points of the reconstruction grid, and was derived from a single PSF acquired experimentally for a 10-μm wide microchannel. For the reconstruction, we used a sparsity-based minimization algorithm. While the conventional image obtained by beamforming the signals measured with all the 128 elements of the probe cannot resolve the individual microchannels, our sparsity-based reconstruction leads to super-resolved images with only 8 elements of the probe (regularly spaced over the full probe aperture), with an image quality comparable to that obtained with all the 128 elements. These results pave the way towards super-resolution in 3D photoacoustic imaging with sparse transducers arrays.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115150809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Deep learning for photoacoustic image reconstruction from incomplete data (Conference Presentation) 基于不完整数据的光声图像重建的深度学习(会议报告)
Photons Plus Ultrasound: Imaging and Sensing 2019 Pub Date : 2019-03-04 DOI: 10.1117/12.2507210
A. Hauptmann, B. Cox, F. Lucka, N. Huynh, M. Betcke, J. Adler, P. Beard, S. Arridge
{"title":"Deep learning for photoacoustic image reconstruction from incomplete data (Conference Presentation)","authors":"A. Hauptmann, B. Cox, F. Lucka, N. Huynh, M. Betcke, J. Adler, P. Beard, S. Arridge","doi":"10.1117/12.2507210","DOIUrl":"https://doi.org/10.1117/12.2507210","url":null,"abstract":"There are occasions, perhaps due to hardware constraints, or to speed-up data acquisition, when it is helpful to be able to reconstruct a photoacoustic image from an under-sampled or incomplete data set. Here, we will show how Deep Learning can be used to improve image reconstruction in such cases. Deep Learning is a type of machine learning in which a multi-layered neural network is trained from a set of examples to perform a task. Convolutional Neural Networks (CNNs), a type of deep neural network in which one or more layers perform convolutions, have seen spectacular success in recent years in tasks as diverse as image classification, language processing and game playing. In this work, a series of CNNs were trained to perform the steps of an iterative, gradient-based, image reconstruction algorithm from under-sampled data. This has two advantages: first, the iterative reconstruction is accelerated by learning more efficient updates for each iterate; second, the CNNs effectively learn a prior from the training data set, meaning that it is not necessary to make potentially unrealistic regularising assumptions about the image sparsity or smoothness, for instance. In addition, we show an example in which the CNNs learn to remove artifacts that arise when a slow but accurate acoustic model is replaced by a fast but approximate model. Reconstructions from simulated as well as in vivo data will be shown.","PeriodicalId":206495,"journal":{"name":"Photons Plus Ultrasound: Imaging and Sensing 2019","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126657709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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