The Moscone Center
San Francisco, California, United States
28 January - 2 February 2017
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Brain Presentations

Clinical Technologies, Laser Tissue Interaction, and Tissue Engineering
(ordered start date and time)


NIRS-based hematoma detector performance testing with molded and 3D-printed phantoms
Paper 10056-4

Author(s):  T. Joshua Pfefer, U.S. Food and Drug Administration (United States), et al.
Conference 10056: Design and Quality for Biomedical Technologies X
Session 2: 3D Printed Phantoms
Date and Time: Saturday, January 28, 2017, 2:20 PM

Phantom-based testing approaches are needed for objective, quantitative performance evaluation of emerging NIRS devices for intracranial hematoma detection. To this end, two types of phantom were developed and tested. The first approach involves a 3D-printed, multi-layer phantom mimicking specific cerebral tissues and incorporating hemoglobin-filled inclusions. The second approach involves molded silicone layers containing a hematoma-mimicking inclusion with simplified geometry. Test results with NIRS devices demonstrate the ability of these approaches to quantitatively evaluate device performance and indicate the promise of using 3D printing to achieve phantoms with realistic variations in tissue optical properties for evaluating biophotonic device performance.


3D-printed biomimetic cerebrovascular phantoms for biophotonic imaging and spectroscopy
Paper 10056-5

Author(s):  Pejhman Ghassemi, U.S. Food and Drug Administration (United States), et al.
Conference 10056: Design and Quality for Biomedical Technologies X
Session 2: 3D Printed Phantoms
Date and Time: Saturday, January 28, 2017, 2:40 PM

We have investigated methods for fabricating 3D-printed cerebrovascular phantoms. This work involved modifying an existing segmented cerebral CT image volume into a printable form, customizing 3D-printed phantom optical properties, cleaning residual uncured photopolymer from vessel-simulating channels and validation of printed phantoms geometry using micro-CT imaging. The cerebral vascular phantoms were then tested by: (a) injecting hemoglobin solutions and imaging with a hyperspectral oximetry system and (b) injecting a mixture of Hb and indocyanine green and performing measurements with a near-infrared fluorescence imaging system. Results indicated that 3D-printed biomimetic phantoms show significant promise for improving assessment of biophotonic diagnostic devices.


Photoacoustic tomography: deep imaging beyond the optical diffusion limit
Paper 10064-1

Author(s):  Lihong V. Wang, Washington Univ. in St. Louis (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 1: Brain Imaging
Date and Time: Sunday, January 29, 2017, 8:00 AM

Photoacoustic tomography (PAT), combining optical and ultrasonic waves via the photoacoustic effect, provides in vivo functional, metabolic, molecular, and histologic imaging. PAT has the unique strength of high-resolution omniscale imaging across the length scales of organelles, cells, tissues, organs, and small-animal organisms with consistent contrast. PAT has the potential to empower multiscale biology research and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system. Coupled with voltage- or calcium-sensitive indicators, PAT holds promise for activity imaging of the whole brain of small animals.


Transcranial optical vascular imaging (TOVI) during cardiac arrest
Paper 10063-2

Author(s):  Vyacheslav Kalchenko, Weizmann Institute of Science (Israel), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session 1: Speckle Technologies
Date and Time: Sunday, January 29, 2017, 8:10 AM

Based on the recent studies the prognosis of patients after cardiac arrest (CA) remains poor. Thus it is extremely important to understand fine mechanisms related to the influence of CA on the brain and Cerebral Blood Flow (CBF) during and after CA. Recently our group introduced Transcranial Optical Vascular Imaging (TOVI) approach that combines laser speckle and dynamic fluorescent imaging. TOVI proved to be useful during various preclinical brain research applications. For example it allows imaging of brain blood vessels of a mouse in vivo through the intact cranium. Herein for the first time we present the use of TOVI during cardiac arrest. TOVI possibly could be a useful tool for preclinical studies of CBF during and after CA.


Towards genetically encoded Indicators for photoacoustic detection of neuronal activity
Paper 10064-2

Author(s):  Robert E. Campbell, Univ. of Alberta (Canada), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 1: Brain Imaging
Date and Time: Sunday, January 29, 2017, 8:30 AM

Interest in genetically encoded indicators of neuronal activity has exploded over the past decade as the tremendous practical utility of these tools has become apparent to the growing number of neuroscientists racing to decipher the inner workings of the brain. While the current generation of visibly fluorescent calcium ion indicators is highly optimized for superficial imaging of neuronal activity, there is growing demand for tools that could enable researchers to visualize activity deeper into the brain. In response to these demands, my research group is working to develop a first generation of genetically encoded indicators with excitation in the near-infrared optical window where tissue is most transparent to light. In this seminar I will present some of our most recent efforts to engineer this next generation of improved far-red and near-infrared calcium ion indicators optimized for both fluorescence and photoacoustic imaging.


Multiscale photoacoustic tomography of GCaMP6-expressing mouse brains
Paper 10064-4

Author(s):  Ruiying Zhang, Washington Univ. in St. Louis (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 1: Brain Imaging
Date and Time: Sunday, January 29, 2017, 9:30 AM

Previous endeavors in photoacoustic (PA) brain studies have focused on measuring relatively slow hemodynamic parameters. Here we combine photoacoustic microscopy (PAM) and photoacoustic computed tomography (PACT) with GCaMP6 mouse brain models for neuronal calcium imaging. The PACT system unambiguously demonstrated wide-field PA calcium imaging of neural activities, even 2 mm beneath a thick scattering medium. We recorded increased PA signals in vivo, in response to hindpaw electrical stimulations. In conclusion, multiscale photoacoustic tomography holds great promise for high resolution and deep penetration imaging of neural activities in vivo.


In vivo deep brain imaging of rats using photoacoustic computed tomography
Paper 10064-5

Author(s):  Li Lin, Washington Univ. in St. Louis (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 1: Brain Imaging
Date and Time: Sunday, January 29, 2017, 9:45 AM

By using 1064 nm illumination from the side, we imaged the full coronal depth of rat brains in vivo. The experiment was performed using a real-time full-ring-array photoacoustic computed tomography (PACT) imaging system. In addition to anatomical imaging of the blood vessels in the brain, we continuously monitored correlations between the two brain hemispheres in one of the coronal planes. The resting states in the coronal plane were measured before and after stroke ligation surgery at a neck artery.


Listening to membrane potential: photoacoustic voltage sensitive dye recording
Paper 10064-6

Author(s):  Haichong K. Zhang, Johns Hopkins Univ. (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 1: Brain Imaging
Date and Time: Sunday, January 29, 2017, 10:00 AM

Monitoring of the membrane potential is possible using voltage sensitive dyes (VSD), which responds to neuronal electrical activity. Here, we have developed a novel photoacoustic VSD capable of detecting the active potential variation. In the polarized state, this cyanine-based probe enhances photoacoustic intensity while decreasing fluorescence output in a lipid vesicle membrane model. Our results not only demonstrate the voltage sensing capability of the dye, but also indicate the necessity of considering both fluorescence and absorption energy transfer in order to optimize the characteristics of novel photoacoustic probes.


Multi-exposure speckle imaging of cerebral blood flow: a pilot clinical study
Paper 10063-8

Author(s):  Lisa M. Richards, The Univ. of Texas at Austin (United States), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session 2: Clinical Imaging
Date and Time: Sunday, January 29, 2017, 11:00 AM

Monitoring cerebral blood flow (CBF) during neurosurgery is essential for detecting ischemia in a timely manner for a wide range of procedures. In this clinical study (n = 7), multi-exposure speckle imaging (MESI) was evaluated intraoperatively during brain tumor resection procedures. The results demonstrate that shorter exposure times (≤1 ms) provide the highest dynamic range and sensitivity for sampling flow rates in human neurovasculature, and that MESI-estimated flows were highly conserved in vascular bifurcations. Results from this study demonstrate the importance of exposure time selection for LSCI, and that intraoperative MESI can be performed with high quantitative accuracy.


Optoacoustic mapping of cerebral blood oxygenation in humans
Paper 10064-9

Author(s):  Yuriy Y. Petrov, The Univ. of Texas Medical Branch (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 2: Clinical Applications
Date and Time: Sunday, January 29, 2017, 11:15 AM

Noninvasive mapping, monitoring, and imaging of cerebral blood is important for management of patients with traumatic brain injury, stroke, and other neurological conditions. We proposed to use optoacoustics for this application, built optoacoustic systems for cerebral blood oxygenation mapping, and tested them in adults and neonates. The systems provide transcranial optoacoustic measurements in the NIR spectral range (680-950 nm). Novel, ultra-sensitive optoacoustic probes were built for detection of optoacoustic signals from large cerebral blood vessels and cerebral tissues. Measurement of the optoacoustic signals at different locations allowed for mapping of cerebral blood oxygenation beneath the skull.


Using OCT-based microangiography for in vivo longitudinal study of arteriogenesis
Paper 10063-14

Author(s):  Yuandong Li, Univ. of Washington (United States), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session 4: OCT Plus Speckle Imaging I
Date and Time: Sunday, January 29, 2017, 3:10 PM

The adaptive growth of collateral vessels, termed “arteriogenesis”, is crucial for maintaining regional blood supply during arterial obstruction and offsetting the adverse effect of tissue ischemia. We present using OCT-based microangiography (OMAG) to image arteriogenesis process longitudinally in mouse cerebral cortex after middle cerebral artery occlusion (MCAO). We imaged the collateral arterioles at the arteriolo-arteriolar anastomosis (AAA) within 7-day period after MCAO to reveal key elements of collateral vessel remodeling, including alteration in vessel morphology, velocity and directionality of blood flow.


Cerebral blood oxygenation measurements in neonates with optoacoustic technique
Paper 10064-25

Author(s):  Stephen Herrmann, The Univ. of Texas Medical Branch (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 4: Functional Imaging
Date and Time: Sunday, January 29, 2017, 5:15 PM

Cerebral hypoxia in neonates results in death and severe complications such as cerebral palsy. We proposed to use optoacoustics for this application by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, OPO- and laser diode-based optoacoustic systems for measurement of SSS blood oxygenation through open anterior and posterior fontanelles as well as through the skull in the occipital area. We tested the systems in neonatal SSS phantoms and in neonates. The systems were capable of detecting SSS signals with high signal-to-noise ratio and provided real-time, continuous oxygenation monitoring with high precision.


EEG microstates are associated with functional NIRS resting brain networks
Paper 10057-23

Author(s):  Olajide M. Babawale, The Univ. of Texas at Arlington (United States), et al.
Conference 10057: Multimodal Biomedical Imaging XII
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM


Relationship between EEG frequency bands and functional NIRS resting state brain networks
Paper 10057-24

Author(s):  Olajide M. Babawale, The Univ. of Texas at Arlington (United States), et al.
Conference 10057: Multimodal Biomedical Imaging XII
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM


Continuous blood pressure recordings simultaneously with functional brain imaging: studies of the glymphatic system
Paper 10063-35

Author(s):  Aleksandra Zienkiewicz, Univ. of Oulu (Finland), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

Over the last few years, studies revealed that the brain contains the so-called glymphatic system, which is the counterpart of the systemic lymphatic system. Similarly, the flow in the glymphatic system is assumed to be mostly driven by physiological pulsations such as cardiovascular pulses. We present our MRI compatible optics based system for continuous blood pressure measurement and show results on the effects of blood pressure variations on cerebral brain dynamics, with a focus on the glymphatic system. Blood pressure was measured simultaneously with near-infrared spectroscopy (NIRS) combined with an ultrafast fMRI sequence (MREG, 3D brain 10 Hz sampling rate).


Intermittent behavior in the brain neuronal network in the perception of ambiguous images
Paper 10063-38

Author(s):  Alexander E. Hramov, Saratov State Technical Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We consider the characteristics of intermittent behavior in the process of bistable visual perception. As intermittency the alternation between two different projections of Necker cube being the ambiguous image is considered. The contrast of the three middle lines centered in the left middle corner was used as a control parameter. The distribution of time interval lengths corresponding to the period of perception of each projection has been obtained for different values of the control parameter and several subjects. To interpret obtained results mathematical approach based on stochastic differential equation with bistable potential has been developed.


Intermittent phase synchronization in human epileptic brain
Paper 10063-40

Author(s):  Olga I. Moskalenko, Saratov State Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We found the intermittent phase synchronization in human epileptic brain. We show that the phases of the synchronous behavior are observed both during the epileptic seizures and in the fields of the background activity of the brain. We estimate the degree of intermittent phase synchronization in both considered cases and found that the epileptic seizures are characterized by the higher degree of synchronization in comparison with the fields of background activity. For estimation of synchronization degree the modification of the method for estimation of zero conditional Lyapunov exponent from time series proposed in [PRE 92 (2015) 012913] has been used.


Recognition and classification of oscillatory patterns of electric brain activity using artificial neural network approach
Paper 10063-41

Author(s):  Alexander E. Hramov, Saratov State Technical Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

The report presents the results of an artificial neural network (ANN) development to analyze the possibility of determining the brain activity patterns corresponding to a perception of the ambiguous images (Necker cube). We have analyzed the fragments of multi-channel EEG, taken after the presentation of the Necker cube. We have shown that trained ANN allows us to identify left-hand/right-hand Necker cube perception with the probability ~80%. We have also estimated the quality of classification for different EEG channels combinations and revealed ones for which the performance of ANN was maximized. The provided analysis demonstrates the possibility of reducing the channels number to be used without degradation of the classification quality of ambiguous image perception.


Filtration of human EEG recordings from physiological artifacts with empirical mode methods
Paper 10063-42

Author(s):  Anastasiya E. Runnova, Yuri Gagarin State Technical Univ. of Saratov (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

The report article presents the recovering EEG brain signals based on adaptive filtering with empirical mode method. The presented method is demonstrated on the example of various experimental data. We show the results of oculomotor filtering artifacts and conduct a comparison of these results with the suppression based on the method of Gram-Schmidt. We analyze a sufficient number of calculated empirical modes for correct recovering the EEG signal. In most cases, it is sufficient to use only the first major empirical mode for adequate signal filtering.


The study of cognitive processes in the brain EEG during the perception of bistable images using wavelet skeleton
Paper 10063-43

Author(s):  Anastasiya E. Runnova, Yuri Gagarin State Technical Univ. of Saratov (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

This report presents the results of experimental studies and mathematical processing of the perception of ambiguous images (Necker cube). Standard 10-20 EEG recording system has been used to record the brain electrical activity for group of volunteers. The method based on the wavelet skeleton calculating for processing EEG records is discovered. We have presented a developed method for objective and automatic estimate the presence and features of a particular oscillatory activity in the multichannel EEG data. The using of the developed methods has determined the time of presentation cubes and moments of decision-making by volunteers with a high degree of accuracy (from 60 to 90% for different subjects).


Pattern formation in adaptive multiplex network in application to analysis of the complex structure of neuronal network of the brain
Paper 10063-46

Author(s):  Alexander E. Hramov, Saratov State Technical Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

In the report we study the mechanisms of pattern formation in the adaptive multiplex network of Kuramoto oscillators with two layers with 300 oscillators on each. The interaction between the nodes on each layer in adaptive network is defined by the principles of competition, i.e., graph of links between nodes co-evolves with the dynamical process of synchronization of nodes. Obtained after adaptation processes the quasi-stationary structure of network corresponds to the topology of scale-free network. This suggests that the studied model can be used to explain the effects observed in the real networks. In particular, obtained results can be applied for explanation of evolution of simple neuronal networks to complex hierarchical structure of real neuronal network of the brain.


Artifact removal from EEG data with empirical mode decomposition
Paper 10063-49

Author(s):  Vadim V. Grubov, Yuri Gagarin State Technical Univ. of Saratov (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We introduce a new method for removing artifacts from EEG signals. As experimental data we consider EEG signals of healthy volunteers with standard physiological probes. Proposed method is based on empirical mode decomposition that decompose initial signal into the set of amplitude-modulated components – empirical modes. Artifact removing method includes empirical mode decomposition of the initial EEG signal, removing of several empirical modes that include artifacts, reconstruction of EEG signal by summarizing the rest empirical modes. The developed method is tested on EEG signals of 15 volunteers. High efficiency in removing of artifacts of different nature from EEG is shown.


Numerical and analytical investigation of the chimera state excitation conditions in the Kuramoto-Sakaguchi oscillator network
Paper 10063-51

Author(s):  Nikita S. Frolov, Saratov State Technical Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We study the chimera excitation state conditions in Kuramoto-Sakaguchi (KS) phase oscillator network with nonlocal coupling using both the numerical simulation of the oscillator network and the theoretical analysis by means of the Ott-Antonsen approach. We have shown that both numerical and the analytical treatment gives the identical description of the network dynamics. In the framework of the analytical Ott-Antonsen approach we have analyzed the conditions of coherent dynamics suppression and the chimera state excitation in the KS network under study at the different values of controlling parameters and the variation of homogeneity of interacting oscillators.


Numerical analysis of the chimera states in the multilayered network model
Paper 10063-53

Author(s):  Vladimir A. Maksimenko, Saratov State Technical Univ. (Russian Federation), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We study the interaction between the ensembles of nonlocaly coupled oscillators, arranged in the multilayer network. We have shown that the fully identical layers, demonstrated individually different chimera, come to the identical chimera state with the increase of inter-layer coupling. Within the multilayer model we also consider the case, when the one layer demonstrates chimera state, while another layer exhibits coherent or incoherent dynamics. It has been shown that the interactions chimera-coherent state and chimera-incoherent state leads to the both excitation of chimera as from the ensemble of fully coherent or incoherent oscillators, and suppression of initially stable chimera state


Functional photoacoustic tomography for neonatal brain imaging: developments and challenges
Paper 10064-105

Author(s):  Mohammadreza Nasiriavanaki, Wayne State Univ. (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

Neurodevelopmental outcome after premature birth is complex, and understanding the neurobiological mechanisms that support brain development after premature birth is crucial. The goal of this study is to implement a functional imaging system to monitor infant brains noninvasively using photoacoustic technology. In addition to several developments, the proposed system in here, is developed based on multiple single element ultrasonic transducers that are configured hemisphericaly. A new side light illumination scheme as well as a semi-dry coupling configuration is used in this system. A novel three dimensional dictionary based compressed sensing reconstruction algorithm is used for image reconstruction.


Study of data analysis methods in functional connectivity photoacoustic tomography (fcPAT)
Paper 10064-114

Author(s):  Ali Hariri, Wayne State Univ. (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

Resting-state functional connectivity (RSFC) is a method to monitor the health of the brain and find out abnormalities in brain networks. Recently functional connectivity photoacoustic tomography (fcPAT) has been used to study RSFC in the mouse brain. The current method of RSFC data analysis is called “seed-based”. This method is not data-driven, and involves user intervention. Alternative signal processing approaches, such as singular value decomposition (SVD) and independent component analysis (ICA), will be explored to complement and cross validate the seed-based approach, possibly substituting them for the seed-based method. The methods are applied on fcPAT data of a mouse brain.


A cost-effective functional connectivity photoacoustic tomography (fcPAT) of the mouse brain
Paper 10064-115

Author(s):  Ali Hariri, Wayne State Univ. (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

The increasing use of mouse models for human brain disease studies, coupled with the fact that existing high-resolution functional imaging modalities cannot be easily applied to mice, presents an emerging need for a new functional imaging modality. Utilizing a novel light illumination scheme and a moving multiple-single-transducer ultrasonic detection, we imaged spontaneous cerebral hemodynamic fluctuations and their associated functional connections in the mouse brain. Correlations were investigated inter-hemispherically between bilaterally homologous regions, as well as intra-hemispherically within the same functional regions. The resultant map can be used in the study of brain disorders such as stroke, Alzheimer’s, schizophrenia and epilepsy.


Toward high-speed transcranial photoacoustic imaging using compact near-infrared pulsed LED illumination system
Paper 10064-117

Author(s):  Jeeun Kang, Johns Hopkins Univ. (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session PSun: Posters-Sunday
Date and Time: Sunday, January 29, 2017, 5:30 PM

We propose high-speed transcranial PA imaging using a novel, compact pulsed LED illumination system (Prexion Inc., Japan) with 200-uJ pulse energy and pulse repetition frequency up to 4kHz at NIR wavelengths of 690-nm and 850-nm switchable in real-time. The preliminary ex vivo experimental results with mice skull and human temporal bone validate the feasibility of the proposed LED light source for high-speed brain sensing by providing significant PA contrast with reasonable frame averaging (16 and 64 for mice and human skull bones).


Simultaneous and co-localized acousto-optic measurements of blood flow and oxygenation
Paper 10059-2

Author(s):  Michal Balberg, Holon Institute of Technology (Israel), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 1: Advances in Instrumentation and Technology I: Flow
Date and Time: Monday, January 30, 2017, 8:30 AM

We demonstrate, using acousto-optics, that local changes in flow rate in a specific layer can be extracted simultaneously and independently of changes in the color of the layer. A phantom model, constructed of different layers of micro-channels at different depths, is illuminated with coherent light, while an ultrasound wave is variably focused on different layers of micro-channels. The temporal broadening of the detected light is measured concurrently with the spatial decay of the amplitude of the modulated signal at the acoustic frequency. A two dimensional map of the color and flow rate at each depth will be presented.


Diffuse speckle contrast analysis with novel fiber-lens detection
Paper 10059-3

Author(s):  Chaebeom Yeo, DGIST (Korea, Republic of), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 1: Advances in Instrumentation and Technology I: Flow
Date and Time: Monday, January 30, 2017, 8:50 AM

To date, various blood flow measurement systems have been presented. Recently we demonstrated multi-channel diffuse speckle contrast analysis (DSCA) to monitor in-vivo relative blood flow in deep tissues noninvasively. It has a limitation in a long-term use due to camera contamination. Here, we present a novel fiber-lens combined DSCA which can solve it. Also it has been applied to cerebral blood flow monitoring of rats during middle cerebral artery occlusion surgery. As a result, the system showed relative changes of the flow during the arterial perfusion periods. It secures novel application of the DSCA in in-vivo blood flow measurement.


Spectroscopic optical coherence tomography for ex vivo brain tumor analysis
Paper 10054-19

Author(s):  Marcel Lenz, Photonics and Terahertz-Technology, Ruhr-Univ. Bochum (Germany), et al.
Conference 10054: Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XV
Session 5: Optical Coherence Tomography: Guidance Applications
Date and Time: Monday, January 30, 2017, 9:30 AM

For neurosurgeries precise tumor resection is essential for the subsequent recovery of the patients since nearby healthy tissue that may be harmed has a huge impact on the life quality after the surgery. To analyze the potential of OCT for distinction between brain tumors and healthy tissue, we used a commercially available Thorlabs Callisto system to measure healthy and meningioma tissue ex vivo. Since an automated distinction between tumor and healthy tissue would be highly desirable to guide the surgeon, we applied Spectroscopic Optical Coherence Tomography, pattern recognition and machine learning algorithms were applied to classify the derived spectroscopic information.


Prototype of an opto-capacitive probe for non-invasive sensing cerebrospinal fluid circulation
Paper 10063-22

Author(s):  Teemu S. Myllylä, Univ. of Oulu (Finland), et al.
Conference 10063: Dynamics and Fluctuations in Biomedical Photonics XIV
Session 7: Functional Imaging
Date and Time: Monday, January 30, 2017, 1:20 PM

In brain studies, the function of the cerebrospinal fluid (CSF) awakes growing interest, particularly related to studies of the so-called glymphatic system in the brain. Our goal is to develop an in vivo method for the non-invasive measurement of cerebral blood flow and CSF circulation by exploiting optical and capacitive sensing techniques simultaneously. We introduce a prototype of a wearable probe that is aimed to be used for long-term brain monitoring purposes, especially focusing on studies of the glymphatic system. Presented prototype probe is tested by measuring liquid flows inside phantoms mimicking the CSF circulation.


Pressure generation during neural stimulation with infrared radiation
Paper 10062-10

Author(s):  Claus-Peter Richter, Northwestern Univ. (United States), et al.
Conference 10062: Optical Interactions with Tissue and Cells XXVIII
Session 3: Photothermal Interactions from Pulsed Lasers
Date and Time: Monday, January 30, 2017, 1:30 PM


System design and performance evaluation of a fluorescence laminar optical tomography scanner for brain studies
Paper 10059-12

Author(s):  Mahya Sheikhzadeh, Univ. of Wisconsin-Milwaukee (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 3: Advances in Instrumentation and Technology III: Fluorescence and Microscopy
Date and Time: Monday, January 30, 2017, 1:50 PM

We present an optimized setup of a tomographic scanner, which enables us to derive quantitative information clarifying the three-dimensional fluorescence distribution in the brain of small rodents. A set of galvanometer mirrors are employed for realization of a fast and flexible scanner while a camera records the emission fluorescence signal. The forward model of the image reconstruction is based on Monte Carlo simulation, and the inverse problem is solved using an iterative reconstruction method. Evaluation carried out on microchannel phantoms and in-vivo imaging of rat brains, clearly indicating enriched application of the system for brain studies on small animals.


Development of a NIRS method to quantify cerebral perfusion and oxidative metabolism in preterm neonates with post hemorrhagic ventricle dilation
Paper 10054-27

Author(s):  Peter McLachlan, Western Univ. (Canada), et al.
Conference 10054: Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XV
Session 7: Near Infrared Spectroscopy and Imaging Applications
Date and Time: Monday, January 30, 2017, 2:10 PM

Preterm neonates with post-hemorrhagic ventricle dilation (PHVD) are at a greater risk of life-long neurological disability possibly due to impaired cerebral perfusion. Cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO2) can be quantified by dynamic contrast-enhanced NIRS. However, PHVD poses unique challenges to NIRS since the cerebral mantle can be compressed to 1 cm or less. We present a finite-slab model for spectral analysis that incorporates mantle thickness measurements from ultrasound images. We apply our technique to 9 patients receiving repeated ventricle taps and assess the magnitude of error when using the standard semi-infinite model.


Development of a hybrid broadband NIRS/diffusion correlation spectroscopy system for real-time monitoring of cerebral perfusion and oxygenation in preterm brain injury
Paper 10054-28

Author(s):  Ajay Rajaram, Lawson Health Research Institute (Canada), et al.
Conference 10054: Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XV
Session 7: Near Infrared Spectroscopy and Imaging Applications
Date and Time: Monday, January 30, 2017, 2:30 PM

Preterm infants have a high risk of neurodevelopmental impairment, their brains are vulnerable to periods of low cerebral blood flow (CBF) that can impair energy metabolism and ultimately cause tissue damage. Optical techniques have provided safe, non-invasive methods of measuring clinical parameters. Near-Infrared Spectroscopy (NIRS) can quantify cerebral oxygen saturation (ScO2) and Diffuse Correlation Spectroscopy (DCS) can describe cerebral blood flow (CBF). We present the development and testing of a portable hybrid NIRS/DCS neuromonitor, unique in its ability to simultaneously utilize NIRS and DCS techniques, providing a bedside measurement of ScO2, CBF, and metabolism in real-time.


The influence of medium conductivity on cells exposed to nsPEF
Paper 10066-30

Author(s):  Erick K. Moen, The Univ. of Southern California (United States), et al.
Conference 10066: Energy-based Treatment of Tissue and Assessment IX
Session 8: Pulsed Electric Fields and Cell/Tissue Effects
Date and Time: Monday, January 30, 2017, 3:30 PM

A recently developed nonlinear optical technique based on Second Harmonic Generation (SHG) imaging is employed to identify the effect solution conductivity has on nsPEF-induced nanoporation. Because the method instantaneously and directly reports on membrane structure, we are able to separate electrophoretic and diffusion-related artifacts from our results. We demonstrate that cells exposed in lower conductivity solution experience increased nanoporation as compared to higher conductivity extracellular solutions. This supports the hypothesis that the membrane charges more quickly when the cytoplasm is comparatively more conductive than the extracellular solution. It also indicates that the electric field dominates conductive effects during membrane nanoporation.


Novel 3-dimensional gold micro-electrodes allow high resolution neural network recording
Paper 10061-41

Author(s):  Pierre J. J. Wijdenes, Univ. of Calgary (Canada), et al.
Conference 10061: Microfluidics, BioMEMS, and Medical Microsystems XV
Session 10: Medical Devices
Date and Time: Monday, January 30, 2017, 4:00 PM

Multi-electrode arrays are neuro-electronic hybrid devices used in multiple fields, ranging from the study of artificial neural networks, drug-screening and diagnostic tools, and may also serve as neural implants for therapeutic purposes. However, the signal-to-noise ratio (SNR) rendered by these devices is often poor, in the µV range, and does not allow unit activity from individual neurons embedded in a network to be determined. In this paper, we report on a new three-dimensional multi-electrode array design, offering recordings in the mV range with a SNR up to 533% higher compared to commercially available devices and others reported in the literature.


Imaging ischemic strokes in rodents using visible-light optical coherence tomography
Paper 10053-22

Author(s):  Siyu Chen, Northwestern Univ. (United States), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session 4: Small Animal
Date and Time: Monday, January 30, 2017, 4:15 PM

We employed optical coherence tomography angiography to monitor cortical hemodynamic changes. To minimize the adverse effect of strong tissue scattering, we developed a novel dual-depth sampling and normalization strategy for visible-light OCT. It could provide precise and robust and blood oxygen saturation (sO2) estimations within cerebral circulation. Using the newly developed method, we monitored the hemodynamic response on mouse cortex following photochemically induced focal ischemic. It was demonstrated that both morphological changes and decrease in blood sO2 occurred following the occlusion. In addition, vascular sO2 map on intact cortex revealed spatial variation of oxygen content within the mouse cerebral circulation.


Detection of cortical optical changes during seizure activity using optical coherence tomography
Paper 10053-23

Author(s):  Danielle Ornelas, Univ. of California, Riverside (United States), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session 4: Small Animal
Date and Time: Monday, January 30, 2017, 4:30 PM

Optical coherence tomography (OCT) is a label-free, high resolution, and minimally invasive imaging technique that can produce depth-resolved cross-sectional and 3D images. We sought to examine non-vascular depth-dependent optical changes directly related to neural activity using OCT. Results from this study show a non-vascular decrease in intensity and attenuation in ex vivo and in vivo seizure models, respectively. Regions exhibiting decreased optical changes show significant temporal correlation to regions of increased electrical activity during seizure.


Rat brain imaging using full field optical coherence microscopy with short multimode fiber probe
Paper 10053-115

Author(s):  Manabu Sato, Yamagata Univ. (Japan), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session PMon: Posters II: Functional and Applications
Date and Time: Monday, January 30, 2017, 5:30 PM

We demonstrated FF OCM using an ultrathin forward-imaging SMMF (short multimode fiber) probe of 50 μm core diameter, 125 μm diameter, and 7.4 mm length. The axial resolution was measured to be 2.20 μm. The lateral resolution was evaluated to be 4.38 μm. The contrast of the OCM images was 6.1 times higher than that of the signal images. Contacting SMMF to the primary somatosensory cortex and the agranular insular cortex of ex vivo rat brain, 3D images (38μm-diameter, 150μm-depth) of the brain were measured, and internal structure information could be obtained. The feasibility of an SMMF has been demonstrated.


Phase-stabilized swept-source OCT for the study of neurovascular coupling
Paper 10053-116

Author(s):  Paul Shin, KAIST (Korea, Republic of), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session PMon: Posters II: Functional and Applications
Date and Time: Monday, January 30, 2017, 5:30 PM

Functional details of the cerebral microvascularture remain unclear because of the lack of temporal resolution of an imaging system compared to the fast vascular response and technical challenges in quantifying cerebral blood flow (CBF) in vivo for longitudinal studies in animals. In this research, we develop a high speed phase-stabilized swept-source OCT system to visualize CBF changes with ~1 s temporal resolution. We perform quantitative measurement of CBF changes at the microscopic level during neuronal activation in the rat somatosensory cortex.


Characterization of reflectance-mode iNIRS system parameters and in vivo comparison with CW-NIRS
Paper 10053-117

Author(s):  Oybek Kholiqov, Univ. of California, Davis (United States), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session PMon: Posters II: Functional and Applications
Date and Time: Monday, January 30, 2017, 5:30 PM

Interferometric near-infrared spectroscopy (iNIRS) is a time-of-flight resolved sensing method that determines optical and dynamic properties of a turbid medium using a rapidly tunable, or frequency swept, light source. The iNIRS system parameters, including sensitivity, dynamic range, bandwidth (tuning range), dynamic coherence time, and instrument response function, are characterized using a current-tuned 855 nm distributed feedback (DFB) laser as the light source, and a novel Mach-Zehnder interferometer variant with a multi-pass loop to efficiently measure the dynamic coherence time of the rapidly tuned laser is introduced. iNIRS is demonstrated in vivo in the mouse brain for continuous monitoring under hypercapnia.


Brain perfusion assessment based on analysis of a derivative of optical signals measured after administration of an optical contrast agent at large source-detector separation
Paper 10059-75

Author(s):  Piotr Sawosz, Nalecz Institute of Biocybernetics and Biomedical Engineering PAS (Poland), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session PMon: Posters-Monday
Date and Time: Monday, January 30, 2017, 5:30 PM

We applied custom-made, high-density diffuse optical tomography in measurements of inflow and washout of an optical contrast agent into a brain. The indocyanine green was injected into a vein of a healthy volunteer, while the optodes were positioned on a head above visual cortex. We observed appearance of the ICG as a drop in optical signals. We analyzed the derivatives of attenuation of optical signals in respect to source-detector separations. The amplitude of the derivative increases with increasing source-detector separation. It suggests, that increase of the source-detector separation improves the sensitivity of the system to a brain perfusion changes.


Design and fabrication of a multi-layered solid dynamic phantom: Validation platform on methods for reducing scalp-hemodynamic effect from fNIRS signal
Paper 10059-76

Author(s):  Hiroshi Kawaguchi, AIST (Japan), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session PMon: Posters-Monday
Date and Time: Monday, January 30, 2017, 5:30 PM

A multi-layered solid dynamic phantom was constructed to validate methods for reducing scalp-hemodynamic effect from fNIRS signal. The phantom consists of 4 layers corresponding to epidermides, dermis and skull (upper dynamic layer), cerebrospinal fluid and brain (lower dynamic layer). Both base parts of upper and lower dynamic layer has a slot for a laterally sliding bar that holds an absorber piece. The optical properties of the materials were estimated from spectrophotometric measurement and indicated similar values to those of the biological tissue. The change in the detected intensity was confirmed during the absorber’s movement in the upper and/or lower dynamic layer.


Accurate quantification of changes in tissue chromophore concentrations by investigating and minimizing effects of DPF: a computational study
Paper 10062-52

Author(s):  Xinlong Wang, The Univ. of Texas at Arlington (United States), et al.
Conference 10062: Optical Interactions with Tissue and Cells XXVIII
Session PMon: Posters-Monday
Date and Time: Monday, January 30, 2017, 5:30 PM

Accurate determination of tissue chromophore concentration changes by broadband near infrared spectroscopy(bb-NIRS) is sensitive to temporal and spectral shapes of DPF(λ, t), due to potential inter-chromophore cross talk. A computer simulation approach was performed to determine quantification errors for commonly used DPF(λ, t) algorithms. The theoretical attenuation spectra with 2%weregenerated by predefined values of chromophore concentration changes. Then,the simulated chromophore concentration changes were inversely fitted using different algorithms of commonly used DPF(λ, t). Approximate 50% underestimation was observed for all DPF(λ, t) algorithms. A proper correction factor was developed as compensation.


Hybrid ultrasound and dual-wavelength optoacoustic biomicroscopy for functional neuroimaging
Paper 10064-174

Author(s):  Johannes Rebling, Technische Univ. München (Germany), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session PMon: Posters-Monday
Date and Time: Monday, January 30, 2017, 5:30 PM

Obtaining morphological and physiological information of neurovasculature is very challenging due to the acoustic attenuation and intense light scattering by the skull. We present a dual-wavelength hybrid-focus optoacoustic microscope (DW-HFOAM), capable of imaging murine neurovasculature in-vivo, with high spatial resolution and over large 3D field of view. The dual wavelength imaging capability further allows for the visualization of functional blood parameters trough an intact skull while pulse-echo ultrasound biomicroscopy images are captured simultaneously by the same scan head. This flexible hybrid system is expected to provide better insights into the architecture and function of the neurovascular system.


Trans-cranial infrared laser stimulation induces hemodynamic and metabolic response measured by broadband near infrared spectroscopy on human forehead
Paper 10062-21

Author(s):  Xinlong Wang, The Univ. of Texas at Arlington (United States), et al.
Conference 10062: Optical Interactions with Tissue and Cells XXVIII
Session 5: Photochemical and Photo-oxidative Interactions
Date and Time: Tuesday, January 31, 2017, 8:40 AM

TILS has shown its potential to benefit a variety of neurological and psychological conditions. However, the physiological mechanism remains unknown. Cytochrome-c-oxidase, the last enzyme in the electron transportation chain, is proposed to be the primary photoacceptor of laser. A placebo-contrasted experimental protocol was applied to 11 human subjects with 8-minute stimulation/placebo and 5-minute recovery. Compared with placebo experiment, significant increases of [CCO],[HbO] and a decrease of [Hb] were observed. In addition, strong linear relationships or interplays between [CCO] versus [HbO] and [CCO] versus [Hb] were observed in vivo for the first time during TILS.


Mapping of electrophysiological response to transcranial infrared laser stimulation on the human brain in vivo measured by electroencephalography
Paper 10062-24

Author(s):  Xinlong Wang, The Univ. of Texas at Arlington (United States), et al.
Conference 10062: Optical Interactions with Tissue and Cells XXVIII
Session 5: Photochemical and Photo-oxidative Interactions
Date and Time: Tuesday, January 31, 2017, 9:40 AM

The TILS has gained increased recognition for its beneficial effects on a variety of neurological and psychological conditions. A 64-channel electroencephalography (EEG) system was employed to monitor human electrophysiological activity before, during and after TILS. A placebo-contrast experimental protocol was also applied. Data analysis methods included (1) root mean square calculation, (2) principal component analysis with independent component analysis, (3) permutation conditional mutual information, and (4) time-frequency wavelet analysis. Differences and similarities in electrophysiology between TILS versus placebo group are discussed, indicating the potential of EEG to be an effective method for monitoring the improvement of TLS therapy.


Bayesian design of structured illumination for diffuse optical tomography of mouse brain
Paper 10059-29

Author(s):  Zachary E. Markow, Washington Univ. in St. Louis (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 7: Theory, Algorithms, and Modeling I
Date and Time: Tuesday, January 31, 2017, 1:30 PM

sCMOS camera-based detection and structured illumination using a digital micromirror device together enable diffuse optical tomography with sufficient spatial and temporal sampling to image hemodynamics related to brain activity in mice. The digital micromirror device's great flexibility in designing illumination patterns and the need for a small number of patterns (<100) per time point to achieve adequate imaging speed necessitate a rational, scalable method for selecting patterns. We employed a Bayesian model of the imaging system to rank candidate illumination pattern sequences based on their ability to reduce uncertainty in reconstructed images.


Statistics of photon penetration depth in diffusive media
Paper 10059-31

Author(s):  Lorenzo Spinelli, CNR-Istituto di Fotonica e Nanotecnologie (Italy), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 7: Theory, Algorithms, and Modeling I
Date and Time: Tuesday, January 31, 2017, 2:10 PM

The study of photon migration through highly scattering media opens the way to the non-invasive investigation of biological tissues well below the skin surface. When the medium is addressed in reflectance geometry, a key issue is to maximize the depth reached by migrating photons. We calculated, for a laterally-infinite slab, the time-resolved and continuous-wave probability density functions (PDFs) for the maximum depth reached by detected photons. From PDFs it is possible to calculate the mean value at which detected photons have undergone scattering events. For these calculations, we exploited both a Monte Carlo code and the Diffusion Equation.


Confocal laser endomicroscopy for brain tumor surgery: a milestone journey from microscopy to cellular surgery
Paper 10060-12

Author(s):  Cleopatra Charalampaki, Medical Ctr. Cologne (Germany), et al.
Conference 10060: Optical Biopsy XV: Toward Real-Time Spectroscopic Imaging and Diagnosis
Session 3: Optical Biopsy: Pathway to Clinical Translation III
Date and Time: Tuesday, January 31, 2017, 2:35 PM


A smart brain biopsy needle integrating an OCT needle probe with automated blood vessel detection in human patients
Paper 10053-49

Author(s):  Robert A. McLaughlin, The Univ. of Adelaide (Australia), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session 8: Clinical Applications
Date and Time: Tuesday, January 31, 2017, 4:00 PM

Brain biopsies are a common neurosurgical technique to provide diagnosis of brain pathologies. However, they have a 2 - 3% risk of causing a significant hemorrhage, resulting in neurological deficit or death. We present a miniaturized OCT imaging probe, integrated into a Medtronic brain biopsy needle. The probe is combined with fully automated blood vessel detection software based on speckle decorrelation to provide interactive feedback as the needle is inserted. For the first time, we demonstrate the use of such a needle in humans, performing superficial measurements on two patients undergoing craniotomies, and show clear distinctions between blood vessels and control tissue.


A three-step reconstruction method for fluorescence molecular tomography based on compressive sensing
Paper 10059-35

Author(s):  Yansong Zhu, Johns Hopkins Univ. (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 8: Theory, Algorithms, and Modeling II
Date and Time: Tuesday, January 31, 2017, 4:00 PM

A three-step reconstruction method based on compressive sensing and consisting of truncated singular value decomposition, a homotopy-based strategy and a maximum-likelihood expectation maximization-based approach, was developed for fluorescence molecular tomography. To validate the algorithm, simulation experiments were conducted with optical properties simulating cortex of the human brain. The result showed our algorithm could accurately reconstruct fluorescence distribution with mean-square-error nearly 60% lower than the pure homotopy-based method. This work is part of the BRAIN initiative effort for ultimate assessment of brain network activity in vivo using near-infrared voltage-sensitive dyes.


Intra-operative mapping of glioma infiltration in vivo in patients using OCT
Paper 10053-50

Author(s):  Carmen Kut, The Johns Hopkins Univ. School of Medicine (United States), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session 8: Clinical Applications
Date and Time: Tuesday, January 31, 2017, 4:15 PM

Brain cancer is aggressive and difficult to treat. There is a critical need to provide intra-operative guidance in brain cancer detection. Our previous work demonstrated a novel, real-time optical property mapping method to detect cancer margins ex vivo in 32 patients and in vivo in mice. Here, we present a pilot study to achieve optical mapping in vivo in 8 patients (50 tissue samples). OCT images were quantitatively analyzed and color-coded optical maps were generated within seconds to provide direct visualization of cancer versus non-cancer. This study demonstrated the OCT’s translational potential for safe, extensive resection of infiltrative brain cancers.


A strategy to measure electrophysiological changes with photoacoustic imaging
Paper 10064-85

Author(s):  Rebecka J. Sepela, Univ. of California, Davis (United States), et al.
Conference 10064: Photons Plus Ultrasound: Imaging and Sensing 2017
Session 13: Molecular Imaging
Date and Time: Wednesday, February 1, 2017, 8:45 AM

We aim to develop exogenous photoacoustic contrast agents to functionally image electrophysiological activity deep in biological tissues. Structural changes in ion channel proteins dictate electrical signaling throughout the body and brain. We have recently developed fluorescent dyes that bind ion channels and report their structural changes. We are exploring whether a similar mechanism can create photoacoustic signal intensity changes. We find that mimicking the chemical environment of ion channel activation results in robust changes in photoacoustic properties of contrast dyes. We are working to capture the photoacoustic signal changes that occur when ion channel proteins activate.


Scattering angle resolved optical coherence tomography for in vivo murine retinal imaging
Paper 10053-59

Author(s):  Michael R. Gardner, The Univ. of Texas at Austin (United States), et al.
Conference 10053: Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXI
Session 9: New OCT Technolgy II
Date and Time: Wednesday, February 1, 2017, 9:00 AM

The eye has been called the 'window into the brain.’ Thus, optical retinal imaging techniques are sensitive to morphological changes associated with central nervous system diseases. Though studies have shown the utility of scattering angle resolved (SAR) OCT for particle sizing and detecting disease states ex-vivo, a compact SAR-OCT system for rodent retinal imaging has not been reported. This work reports an SAR-OCT system using a partial glass window, a dual axis MEMS mirror, a high NA objective and fast scan rates for improved investigative capabilities of murine models. Longitudinal mouse studies demonstrate the system’s diagnostic potential.


Continuous monitoring of cerebral hemodynamics during extracorporeal membrane oxygenation therapy
Paper 10060-24

Author(s):  David R. Busch, The Children's Hospital of Philadelphia (United States), et al.
Conference 10060: Optical Biopsy XV: Toward Real-Time Spectroscopic Imaging and Diagnosis
Session 5: Raman and Light Scattering Methods
Date and Time: Wednesday, February 1, 2017, 9:00 AM

Extra corporal membrane oxygenation is the ultimate, temporary treatment modality for life-threatening cardiopulmonary disorders. However, there are currently no bedside tools to provide clinicians with real time feedback to titrate flow rates to an individual's current needs. This is of particular concern for the brain: current clinical tools utilize slowly-varying systemic parameters as a proxy for brain health. We utilize diffuse optics to continuously and non-invasively probe cerebral hemodynamics throughout modulation of this therapy. These tools have the potential to provide real time feedback for continuously adjusted individualized therapy.


Nonlocal correlations of polarization-entangled photons through brain tissue
Paper 10060-27

Author(s):  Enrique J. Galvez, Colgate Univ. (United States), et al.
Conference 10060: Optical Biopsy XV: Toward Real-Time Spectroscopic Imaging and Diagnosis
Session 6: Polarization Methods
Date and Time: Wednesday, February 1, 2017, 10:30 AM

We investigated the preservation of non-local correlations between polarization-entangled photons when one of them traveled through brain tissue slices of different thicknesses. Using down-converted photons at a wavelength of 802 nm minimized the absorption by the tissue. After the light passed through the tissue samples, we performed quantum state tomography to obtain quantitative measures of the entanglement. We found that entanglement is preserved to a surprising degree, and when it degrades, it does so following a particular path in a tangle versus linear-entropy graph. Such a trajectory reveals direct transfer of probability from entangled to mixed state.


Bedside mapping of brain function during acute stroke recovery using high-density diffuse optical tomography
Paper 10059-48

Author(s):  Adam T. Eggebrecht, Washington Univ. School of Medicine in St. Louis (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 10: Brain, Neuro, and Functional Imaging I
Date and Time: Wednesday, February 1, 2017, 11:20 AM

We developed a portable high-density DOT system with a field of view that includes sensory, motor, and cognitive functional brain regions along with data quality metrics such as real-time cap coupling and automated motion artifact detection. We collected up to an hour of resting state DOT and behavioral data (NIH stroke scale to measure behavioral dysfunction) from 44 patients in the first 72 hr phase of recovery from an ischemic stroke. The level of disruption in maps of functional connectivity DOT of [HbO] data were shown to be significantly correlated with behavioral deficit due to the stroke.


New insight in image registration during Transcranial Optical Vascular Imaging (TOVI)
Paper 10060-33

Author(s):  Vyacheslav Kalchenko, Weizmann Institute of Science (Israel), et al.
Conference 10060: Optical Biopsy XV: Toward Real-Time Spectroscopic Imaging and Diagnosis
Session 7: Advanced Imaging Methods
Date and Time: Wednesday, February 1, 2017, 1:55 PM

Transcranial Optical Vascular Imaging (TOVI). TOVI – is a technique that utilizes dynamic fluorescence for characterization of cerebral blood vessels and quantification of cerebral blood flow through the intact cranium. We demonstrate the usability of an adaptive approach to stabilize acquired jerked and distorted images that are characterized by significant structural and intensity changes during acquisition. We confident that our adaptive approach would be useful tool during intravital fluorescent imaging as a stand-alone approach or in combination with standard registration methods such as correlation techniques based on Fourier transforms.


A fast atlas-guided high density diffuse optical tomography system for brain imaging
Paper 10059-52

Author(s):  Xianjin Dai, Dept. of Biomedical Engineering, Univ. of Florida (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 11: Brain, Neuro, and Functional Imaging II
Date and Time: Wednesday, February 1, 2017, 2:10 PM


A compact dual wavelengths time-domain fNIRS system
Paper 10059-53

Author(s):  Davide Contini, Politecnico di Milano (Italy), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 11: Brain, Neuro, and Functional Imaging II
Date and Time: Wednesday, February 1, 2017, 2:30 PM

We proposed a novel compact time-domain fNIRS system based on solid state technology. We developed a one-channel system with two wavelengths in order to estimate the hemoglobin content in tissue. The system is very compact (16x22x5 cm). As pulsed light source, we chose two laser diodes operating in gain switching, the detector is based on a silicon photomultiplier and the acquisition electronics is based on a Time to Digital Converter chip The compactness of this device and the possibility to be battery operated (power consumption is < 10 W) pave the way to numerous applications.


Cerebral hemodynamic responses to hypocapnia and hypercapnia: multi-wavelength time-resolved NIRS studies
Paper 10059-54

Author(s):  Anna Gerega, Nalecz Institute of Biocybernetics and Biomedical Engineering PAS (Poland), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 11: Brain, Neuro, and Functional Imaging II
Date and Time: Wednesday, February 1, 2017, 2:50 PM

We applied a time-resolved NIRS instrument in diffuse reflectance measurements at multiple wavelengths simultaneously in order to investigate the cerebral hemodynamic changes during controlled hypo- and hypercapnia. The optical signal were collected at 16 wavelengths from 650-850nm spectral region after the light penetration into the head. The changes of the optical spectra over all detected wavelengths were clearly distinguished due to absorption changes related to changes of hemoglobins concentration during controlled hypocapnia and hypercapnia tests. The recorded distributions of times of flight of photons were analyzed by calculating theirstatistical moments, which show a different sensitivity to changes in absorption in tissue at different depths, which allows for precise estimation of hemodynamic parameters.


Optical measurement of cerebral blood flow during orthostatic manipulation in healthy and diseased populations
Paper 10060-53

Author(s):  David R. Busch, The Children's Hospital of Philadelphia (United States), et al.
Conference 10060: Optical Biopsy XV: Toward Real-Time Spectroscopic Imaging and Diagnosis
Session 7: Advanced Imaging Methods
Date and Time: Wednesday, February 1, 2017, 2:55 PM

Posture impacts cerebral blood flow (CBF) and this effect is regularly utilized therapeutically. However, there are limited tools to assess CBF continuously throughout postural manipulations. We utilize diffuse correlation spectroscopy to measure CBF and present a pooled analysis of 126 healthy and diseased subjects. We identify a subpopulation for whom CBF is lower in the supine, compared to seated, position and demonstrate a hysteresis effect in supine blood flow, in which the post-manipulation supine CBF is higher than pre-manipulation.


Noninvasive Monitoring of Cerebral Autoregulation with Diffuse Correlation Spectroscopy in Brain-injured patients
Paper 10059-55

Author(s):  Lian He, Univ. of Pennsylvania (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 11: Brain, Neuro, and Functional Imaging II
Date and Time: Wednesday, February 1, 2017, 3:10 PM

This study used multimodal brain monitoring (MMM) to provide continuous measurement of physiological events on patients after traumatic brain injury. In particular, diffuse correlation spectroscopy (DCS) was applied for noninvasive measurement of cerebral blood flow (CBF). CBF was compared with mean arterial pressure (MAP) and intracranial pressure (ICP) to understand the mechanisms of brain injury. During monitoring, Nicardipine was injected to the patient to reduce blood pressure. Measurement results indicated DCS evaluation was able to detect impaired CA by comparing the relationship with MAP. Pressure reactivity index (PRx) can also provide useful information in detecting impaired CA and passive cerebral vasculature.


The changes of cerebral hemodynamics during ketamine induced sedation in a rat model
Paper 10059-56

Author(s):  Jay Young Bae, Gwangju Institute of Science and Technology (Korea, Republic of), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 12: Brain, Neuro, and Functional Imaging III
Date and Time: Wednesday, February 1, 2017, 4:00 PM

Ketamine is a NMDA receptor antagonist and shows very distinctive features among other anesthetic agents. Ketamine is the only intravenous anesthetic agent which has excitatory CNS effects. Owing to this difference, existing EEG-based anesthetic depth monitoring method cannot be applied to ketamine. In this study, we employed a near-infrared spectroscopy (NIRS) to observe cerebral hemodynamic changes induced by ketamine in rats to see if NIRS can be used to monitor the depth of sedation non-invasively in a real-time.


Frontal hemodynamic changes during photothrombotic ischemia using diffuse reflectance spectroscopy
Paper 10059-57

Author(s):  Seonghyun Kim, Gwangju Institute of Science and Technology (Korea, Republic of), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 12: Brain, Neuro, and Functional Imaging III
Date and Time: Wednesday, February 1, 2017, 4:20 PM

Despite the mechanism of diaschisis is very important to know, it is not yet fully understood. PET or fMRI imaging technique may provide key answers to a question of how diaschisis occurs. However, a longitudinal study to monitor how ischemic stroke is connected with diaschisis occurrence is not easy to perform using aforementioned systems. This study aims to find differences between pre- and post-stroke state in terms of frontal hemodynamics using diffuse optical spectroscopy which will be the first step to find a connection between ischemic stroke and diaschisis.


The monitoring of cerebral oxygenation with a variation of isoflurane concentration in a rat model
Paper 10059-58

Author(s):  Dong-Hyuk Choi, Gwangju Institute of Science and Technology (Korea, Republic of), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 12: Brain, Neuro, and Functional Imaging III
Date and Time: Wednesday, February 1, 2017, 4:40 PM

We aimed to investigate experimentally how anesthetic levels affect cerebral metabolism measured by near-infrared spectroscopy (NIRS) in rats under isoflurane anesthesia. The NIRS and local field potential (LFP) signals from the frontal cortex were continuously monitored with change of isoflurane concentration. The level of oxyhemoglobin and total hemoglobin concentration decreased gradually as isoflurane concentration is reduced while deoxyhemoglobin increased. The reflectance ratio between 730nm and 850nm and burst suppression ratio (BSR) correspond similarly with the change of oxyhemoglobin concentration. These results suggest that NIRS signals in addition to EEG may provide a possibility of developing a new anesthetic depth index.


Influence of intracranial pressure on cerebral hemodynamic changes measured with near infrared spectroscopy
Paper 10059-59

Author(s):  Alexander Ruesch, Carnegie Mellon Univ. (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 12: Brain, Neuro, and Functional Imaging III
Date and Time: Wednesday, February 1, 2017, 5:00 PM

Cerebral autoregulation (CA) is vital for brain perfusion and health. Monitoring of CA can be achieved via the pressure reactivity index (PRx), which is based on correlation between intracranial pressure (ICP) and mean arterial blood pressure (MAP). However, this method is not viable when ICP monitoring is unavailable and when ICP changes occur without MAP changes. We used near-infrared spectroscopy (NIRS) to measure cerebral hemodynamic changes in non-human primates. A NIRS based approach as an alternative to PRx will be presented, while we also address the dependence of CA as a function of ICP changes rather than MAP changes.


Assessments of cerebral autoregulation in extracorporeal support based on wavelet transform coherence (WTC)
Paper 10059-60

Author(s):  Fenghua Tian, The Univ. of Texas at Arlington (United States), et al.
Conference 10059: Optical Tomography and Spectroscopy of Tissue XII
Session 12: Brain, Neuro, and Functional Imaging III
Date and Time: Wednesday, February 1, 2017, 5:20 PM

Extracorporeal membrane oxygenation (ECMO) is a form of advanced cardio-respiratory support provided to critically ill patients with severe respiratory and/or cardiovascular failure. It is associated with significant mortality and morbidity attributed to a number of pre-ECMO and ECMO-related factors. In this study, we assessed the cerebral autoregulation in patients during extracorporeal support (N = 27) and explored its potential role for developing cerebral injuries. Wavelet transform coherence (WTC) was applied to quantify the nonstationary cross-correlation between mean arterial pressure and cerebral tissue oxygen saturation. Our results show impaired cerebral autoregulation is an early indicator of acute cerebral injuries.


Important Dates

Abstracts Due
17 July 2017

Author Notification
25 September 2017

Manuscripts Due
See Individual Conferences


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Journal of Biomedical Optics

Journal of Biomedical OpticsPublishes peer-reviewed papers that utilize modern optical technology for improved health care and biomedical research.