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Biomedical Optics Express

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https://www.readbyqxmd.com/read/29984110/fiber-based-visible-and-near-infrared-optical-coherence-tomography-vnoct-enables-quantitative-elastic-light-scattering-spectroscopy-in-human-retina
#1
Weiye Song, Libo Zhou, Sui Zhang, Steven Ness, Manishi Desai, Ji Yi
Elastic light scattering spectroscopy (ELSS) has been proven a powerful method in measuring tissue structures with exquisite nanoscale sensitivity. However, ELSS contrast in the living human retina has been relatively underexplored, primarily due to the lack of imaging tools with a large spectral bandwidth. Here, we report a simple all fiber-based setup to implement dual-channel visible and near infrared (NIR) optical coherence tomography (vnOCT) for human retinal imaging, bridging over a 300nm spectral gap...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984109/real-time-visualization-of-two-photon-fluorescence-lifetime-imaging-microscopy-using-a-wavelength-tunable-femtosecond-pulsed-laser
#2
Jiheun Ryu, Ungyo Kang, Jayul Kim, Hyunjun Kim, Jue Hyung Kang, Hyunjin Kim, Dae Kyung Sohn, Jae-Heon Jeong, Hongki Yoo, Bomi Gweon
A fluorescence lifetime imaging microscopy (FLIM) integrated with two-photon excitation technique was developed. A wavelength-tunable femtosecond pulsed laser with nominal pulse repetition rate of 76-MHz was used to acquire FLIM images with a high pixel rate of 3.91 MHz by processing the pulsed two-photon fluorescence signal. Analog mean-delay (AMD) method was adopted to accelerate the lifetime measurement process and to visualize lifetime map in real-time. As a result, rapid tomographic visualization of both structural and chemical properties of the tissues was possible with longer depth penetration and lower photo-damage compared to the conventional single-photon FLIM techniques...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984108/visualization-of-drug-distribution-of-a-topical-minocycline-gel-in-human-facial-skin
#3
Sinyoung Jeong, Maiko Hermsmeier, Sam Osseiran, Akira Yamamoto, Usha Nagavarapu, Kin F Chan, Conor L Evans
Acne vulgaris is a common chronic skin disease in young adults caused by infection of the pilosebaceous unit, resulting in pimples and possibly permanent scarring on the skin. Minocycline, a common antibiotic, has been widely utilized as a systemic antimicrobial treatment for acne via oral administration. Recently, a topical minocycline gel (BPX-01) was developed to directly deliver minocycline through the epidermis and into the pilosebaceous unit to achieve localized treatment with lower doses of drug. As the effectiveness of the drug is directly related to its successful delivery, there is a need to evaluate the pharmacokinetics at the cellular level within tissue...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984107/on-chip-light-sheet-fluorescence-imaging-flow-cytometry-at-a-high-flow-speed-of-1-m-s
#4
Taichi Miura, Hideharu Mikami, Akihiro Isozaki, Takuro Ito, Yasuyuki Ozeki, Keisuke Goda
We present on-chip fluorescence imaging flow cytometry by light-sheet excitation on a mirror-embedded microfluidic chip. The method allows us to obtain microscopy-grade fluorescence images of cells flowing at a high speed of 1 m/s, which is comparable to the flow speed of conventional non-imaging flow cytometers. To implement the light-sheet excitation of flowing cells in a microchannel, we designed and fabricated a mirror-embedded PDMS-based microfluidic chip. To show its broad utility, we used the method to classify large populations of microalgal cells ( Euglena gracilis ) and human cancer cells (human adenocarcinoma cells)...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984106/assessment-of-the-radiotherapy-effect-for-nasopharyngeal-cancer-using-plasma-surface-enhanced-raman-spectroscopy-technology
#5
Qiong Wu, Sufang Qiu, Yun Yu, Weiwei Chen, Huijing Lin, Duo Lin, Shangyuan Feng, Rong Chen
Nasopharyngeal cancer (NPC) is a malignant tumor of the head and neck, which is extremely sensitive to radiotherapy. The aim of this study is to evaluate the feasibility of a label-free nanobiosensor based on plasma surface-enhanced Raman spectroscopy (SERS) to assess the radiotherapy effect in NPC. Here, SERS measurements were performed on plasma samples from 40 pre-treatment and post-treatment NPC as well as 30 healthy volunteers. Results demonstrate that the spectral characteristic of post-treatment samples is obviously different from that of pre-treatment ones, owing to the changes of biomolecules in plasma induced by radiotherapy...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984105/near-simultaneous-quantification-of-glucose-uptake-mitochondrial-membrane-potential-and-vascular-parameters-in-murine-flank-tumors-using-quantitative-diffuse-reflectance-and-fluorescence-spectroscopy
#6
Caigang Zhu, Hannah L Martin, Brian T Crouch, Amy F Martinez, Martin Li, Gregory M Palmer, Mark W Dewhirst, Nimmi Ramanujam
The shifting metabolic landscape of aggressive tumors, with fluctuating oxygenation conditions and temporal changes in glycolysis and mitochondrial metabolism, is a critical phenomenon to study in order to understand negative treatment outcomes. Recently, we have demonstrated near-simultaneous optical imaging of mitochondrial membrane potential (MMP) and glucose uptake in non-tumor window chambers, using the fluorescent probes tetramethylrhodamine ethyl ester (TMRE) and 2-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG)...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984104/real-time-localization-of-the-parathyroid-gland-in-surgical-field-using-raspberry-pi-during-thyroidectomy-a-preliminary-report
#7
Yikeun Kim, Sung Won Kim, Kang Dae Lee, Yeh-Chan Ahn
We created an auto-para viewer, an autofluorescence imaging device, to localize the parathyroid glands during thyroidectomy using an inexpensive Raspberry Pi. A special emission filter in the auto-para viewer was designed to pass 1/100 of visible light and nearly all infrared light longer than 808 nm. With this emission filter, we simultaneously acquired an autofluorescence image of the parathyroid and a visible light image of the surrounding surgical field. The auto-para viewer displayed four times brighter autofluorescence of the parathyroid glands compared to the background tissues without operating room light...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984103/new-fluorescent-compounds-produced-by-femtosecond-laser-surgery-in-biological-tissues-the-mechanisms
#8
Zhongya Qin, Qiqi Sun, Yue Lin, Sicong He, Xuesong Li, Congping Chen, Wanjie Wu, Yi Luo, Jianan Y Qu
The femtosecond laser ablation in biological tissue produces highly fluorescent compounds that are of great significance for intrinsically labelling ablated tissue in vivo and achieving imaging-guided laser microsurgery. In this study, we analyzed the molecular structures of femtosecond laser-ablated tissues using Raman spectroscopy and transmission electron microscopy. The results showed that though laser ablation caused carbonization, no highly fluorescent nanostructures were found in the ablated tissues...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984102/volumetric-non-local-means-based-speckle-reduction-for-optical-coherence-tomography
#9
Carlos Cuartas-Vélez, René Restrepo, Brett E Bouma, Néstor Uribe-Patarroyo
We present a novel tomographic non-local-means based despeckling technique, TNode, for optical coherence tomography. TNode is built upon a weighting similarity criterion derived for speckle in a three-dimensional similarity window. We present an implementation using a two-dimensional search window, enabling the despeckling of volumes in the presence of motion artifacts, and an implementation using a three-dimensional window with improved performance in motion-free volumes. We show that our technique provides effective speckle reduction, comparable with B-scan compounding or out-of-plane averaging, while preserving isotropic resolution, even to the level of speckle-sized structures...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984101/temporally-and-spatially-adaptive-doppler-analysis-for-robust-handheld-optical-coherence-elastography
#10
Xuan Liu, Farzana R Zaki, Haokun Wu, Chizhong Wang, Yahui Wang
Optical coherence elastography (OCE), a functional extension of optical coherence tomography (OCT), can be used to characterize the mechanical properties of biological tissue. A handheld fiber-optic OCE instrument will allow the clinician to conveniently interrogate the localized mechanical properties of in vivo tissue, leading to better informed clinical decision making. During handheld OCE characterization, the handheld probe is used to compress the sample and the displacement of the sample is quantified by analyzing the OCT signals acquired...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984100/selective-retina-therapy-enhanced-with-optical-coherence-tomography-for-dosimetry-control-and-monitoring-a-proof-of-concept-study
#11
Daniel Kaufmann, Christian Burri, Patrik Arnold, Volker M Koch, Christoph Meier, Boris Považay, Jörn Justiz
Selective treatment of the retinal pigment epithelium (RPE) by using short-pulse lasers leads to a less destructive treatment for certain retinal diseases in contrast to conventional photocoagulation. The introduction of selective retina therapy (SRT) to clinical routine is still precluded by the challenges to reliably monitor treatment success and to automatically adjust dose within the locally varying therapeutic window. Combining micrometer-scale depth resolving capabilities of optical coherence tomography (OCT) with SRT can yield real-time information on the laser-induced changes within the RPE after a laser pulse or even during treatment with a laser pulse train...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984099/solving-fourier-ptychographic-imaging-problems-via-neural-network-modeling-and-tensorflow
#12
Shaowei Jiang, Kaikai Guo, Jun Liao, Guoan Zheng
Fourier ptychography is a recently developed imaging approach for large field-of-view and high-resolution microscopy. Here we model the Fourier ptychographic forward imaging process using a convolutional neural network (CNN) and recover the complex object information in a network training process. In this approach, the input of the network is the point spread function in the spatial domain or the coherent transfer function in the Fourier domain. The object is treated as 2D learnable weights of a convolutional or a multiplication layer...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984098/on-the-dysfunctional-hemoglobins-and-cyanosis-connection-practical-implications-for-the-clinical-detection-and-differentiation-of-methemoglobinemia-and-sulfhemoglobinemia
#13
Stephen W Askew, Gladimir V G Baranoski
Methemoglobinemia and sulfhemoglobinemia are potentially life-threatening blood-related disorders characterized by similar symptoms and markedly distinct treatment procedures. In this paper, we investigate the causal relationship between these conditions and the onset of cyanosis, which is typically associated with a purple or bluish skin coloration. More specifically, we perform controlled experiments to elicit cyanotic appearances resulting from different severity levels of these disorders and varying physiological conditions...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984097/weighting-function-effects-in-a-direct-regularization-method-for-image-guided-near-infrared-spectral-tomography-of-breast-cancer
#14
Jinchao Feng, Shudong Jiang, Brian W Pogue, Keith Paulsen
Structural image-guided near-infrared spectral tomography (NIRST) has been developed as a way to use diffuse NIR spectroscopy within the context of image-guided quantification of tissue spectral features. A direct regularization imaging (DRI) method for NIRST has the value of not requiring any image segmentation. Here, we present a comprehensive investigational study to analyze the impact of the weighting function implied when weighting the recovery of optical coefficients in DRI based NIRST. This was done using simulations, phantom and clinical patient exam data...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984096/drunet-a-dilated-residual-u-net-deep-learning-network-to-segment-optic-nerve-head-tissues-in-optical-coherence-tomography-images
#15
Sripad Krishna Devalla, Prajwal K Renukanand, Bharathwaj K Sreedhar, Giridhar Subramanian, Liang Zhang, Shamira Perera, Jean-Martial Mari, Khai Sing Chin, Tin A Tun, Nicholas G Strouthidis, Tin Aung, Alexandre H Thiéry, Michaël J A Girard
Given that the neural and connective tissues of the optic nerve head (ONH) exhibit complex morphological changes with the development and progression of glaucoma, their simultaneous isolation from optical coherence tomography (OCT) images may be of great interest for the clinical diagnosis and management of this pathology. A deep learning algorithm (custom U-NET) was designed and trained to segment 6 ONH tissue layers by capturing both the local (tissue texture) and contextual information (spatial arrangement of tissues)...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984095/machine-learning-based-segmentation-of-the-optic-nerve-head-using-multi-contrast-jones-matrix-optical-coherence-tomography-with-semi-automatic-training-dataset-generation
#16
Deepa Kasaragod, Shuichi Makita, Young-Joo Hong, Yoshiaki Yasuno
A pixel-by-pixel tissue classification framework using multiple contrasts obtained by Jones matrix optical coherence tomography (JM-OCT) is demonstrated. The JM-OCT is an extension of OCT that provides OCT, OCT angiography, birefringence tomography, degree-of-polarization uniformity tomography, and attenuation coefficient tomography, simultaneously. The classification framework consists of feature engineering, k -means clustering that generates a training dataset, training of a tissue classifier using the generated training dataset, and tissue classification by the trained classifier...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984094/automatic-quantification-of-choroidal-neovascularization-lesion-area-on-oct-angiography-based-on-density-cell-like-p-systems-with-active-membranes
#17
Jie Xue, Acner Camino, Steven T Bailey, Xiyu Liu, Dengwang Li, Yali Jia
Detecting and quantifying the size of choroidal neovascularization (CNV) is important for the diagnosis and assessment of neovascular age-related macular degeneration. Depth-resolved imaging of the retinal and choroidal vasculature by optical coherence tomography angiography (OCTA) has enabled the visualization of CNV. However, due to the prevalence of artifacts, it is difficult to segment and quantify the CNV lesion area automatically. We have previously described a saliency algorithm for CNV detection that could identify a CNV lesion area with 83% accuracy...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984093/prediction-of-the-anti-glioma-therapeutic-effects-of-temozolomide-through-in-vivo-molecular-imaging-of-mmp-expression
#18
Li Li, Yang Du, Dehui Xiang, Liang Chen, Zhifeng Shi, Jie Tian, Xinjian Chen
Currently, there is no effective way to assess the therapeutic response of temozolomide (TMZ) for the glioma. In this study, the human U87MG-fLuc glioma animal models were set up and the antitumor efficacy of TMZ was evaluated using bioluminescence imaging (BLI) and MRI. Then, bioluminescence tomography (BLT) was reconstructed using an adaptive sparsity matching pursuit (ASMP) algorithm. Second, the expression level of the MMP-750 probe was examined with or without TMZ treatment using FMI. Third, the expression of MMP2 and MMP3 was specifically examined after treatment...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984092/glare-free-retinal-imaging-using-a-portable-light-field-fundus-camera
#19
Douglas W Palmer, Thomas Coppin, Krishan Rana, Donald G Dansereau, Marwan Suheimat, Michelle Maynard, David A Atchison, Jonathan Roberts, Ross Crawford, Anjali Jaiprakash
We present the retinal plenoptoscope, a novel light field retinal imaging device designed to overcome many of the problems that limit the use of portable non-mydriatic fundus cameras, including image quality and lack of stereopsis. The design and prototype construction of this device is detailed and the ideal relationship between the eye pupil, system aperture stop and micro-image separation is investigated. A comparison of the theoretical entrance pupil size, multi-view baseline and depth resolution indicates that a higher degree of stereopsis is possible than with stereo fundus cameras...
July 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29984091/erratum-visualization-of-laser-tattoo-removal-treatment-effects-in-a-mouse-model-by-two-photon-microscopy-erratum
#20
Won Hyuk Jang, Yeoreum Yoon, Wonjoong Kim, Soonjae Kwon, Seunghun Lee, Duke Song, Jong Woon Choi, Ki Hean Kim
[This corrects the article on p. 3735 in vol. 8, PMID: 28856046.].
July 1, 2018: Biomedical Optics Express
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