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Biomedical Optics Express

Michael G Giacomelli, Tadayuki Yoshitake, Lucas C Cahill, Hilde Vardeh, Liza M Quintana, Beverly E Faulkner-Jones, Jeff Brooker, James L Connolly, James G Fujimoto
The ability to histologically assess surgical specimens in real-time is a long-standing challenge in cancer surgery, including applications such as breast conserving therapy (BCT). Up to 40% of women treated with BCT for breast cancer require a repeat surgery due to postoperative histological findings of close or positive surgical margins using conventional formalin fixed paraffin embedded histology. Imaging technologies such as nonlinear microscopy (NLM), combined with exogenous fluorophores can rapidly provide virtual H&E imaging of surgical specimens without requiring microtome sectioning, facilitating intraoperative assessment of margin status...
May 1, 2018: Biomedical Optics Express
Sreyankar Nandy, Ian S Hagemann, Matthew A Powell, Cary Siegel, Quing Zhu
About 85-90% of all ovarian cancers are carcinomas; these manifest clinically as mass-forming epithelial proliferations involving the ovary. In this study, a visible light spatial frequency domain imaging (SFDI) system was used for multispectral ex vivo imaging and quantitative evaluation of freshly excised benign and malignant human ovarian tissues. A total of 14 ovaries from 11 patients undergoing oophorectomy were investigated. Using a logistic regression model with seven significant spectral and spatial features extracted from SFDI images, a sensitivity of 94...
May 1, 2018: Biomedical Optics Express
Anna Ezerskaia, Natallia Eduarda Uzunbajakava, Gerwin J Puppels, Johanna de Sterke, Peter J Caspers, H Paul Urbach, Babu Varghese
We demonstrate the feasibility of short wave infrared (SWIR) spectroscopy combined with tape stripping for depth profiling of lipids and water in the stratum corneum of human skin. The proposed spectroscopic technique relies on differential detection at three wavelengths of 1720, 1750, and 1770 nm, with varying ratio of the lipid-to-water absorption coefficient and an 'isosbestic point'. Comparison of the data acquired using SWIR spectroscopy with that obtained by a gold standard for non-invasive quantitative molecular-specific skin measurements, namely confocal Raman spectroscopy (CRS), revealed specificity of the proposed modality for water and lipid quantification...
May 1, 2018: Biomedical Optics Express
Vytautas Zickus, Jonathan M Taylor
We present SPIM-μPIV as a flow imaging system, capable of measuring in vivo flow information with 3D micron-scale resolution. Our system was validated using a phantom experiment consisting of a flow of beads in a 50 μm diameter FEP tube. Then, with the help of optical gating techniques, we obtained 3D + time flow fields throughout the full heartbeat in a ∼3 day old zebrafish larva using fluorescent red blood cells as tracer particles. From this we were able to recover 3D flow fields at 31 separate phases in the heartbeat...
May 1, 2018: Biomedical Optics Express
Vitor B Pelegati, Bernardo B C Kyotoku, Lazaro A Padilha, Carlos L Cesar
Acquiring images of biological tissues and cells without the assistance of exogenous labels with a fast repetition rate and chemical specificity is what coherent anti-Stokes Raman Scattering (CARS) imaging offers. Nonresonant background (NRB) is one of the main drawbacks of the CARS microscopy technique because it limits the detection of weak Raman lines and the detection of low-concentration molecules. We show that a six-wave mixing process with two beams, which is a cascade effect of CARS, show better signal/NRB ratio and can be utilized for biological tissues imaging...
May 1, 2018: Biomedical Optics Express
Bingyao Tan, Alexander Wong, Kostadinka Bizheva
A novel image processing algorithm based on a modified Bayesian residual transform (MBRT) was developed for the enhancement of morphological and vascular features in optical coherence tomography (OCT) and OCT angiography (OCTA) images. The MBRT algorithm decomposes the original OCT image into multiple residual images, where each image presents information at a unique scale. Scale selective residual adaptation is used subsequently to enhance morphological features of interest, such as blood vessels and tissue layers, and to suppress irrelevant image features such as noise and motion artefacts...
May 1, 2018: Biomedical Optics Express
Inwon Park, Kibaek Choe, Howon Seo, Yoonha Hwang, Eunjoo Song, Jinhyo Ahn, You Hwan Jo, Pilhan Kim
Direct intravital imaging of an endothelial surface layer (ESL) in pulmonary microcirculation could be a valuable approach to investigate the role of a vascular endothelial barrier in various pathological conditions. Despite its importance as a marker of endothelial cell damage and impairment of the vascular system, in vivo visualization of ESL has remained a challenging technical issue. In this work, we implemented a pulmonary microcirculation imaging system integrated to a custom-design video-rate laser scanning confocal microscopy platform...
May 1, 2018: Biomedical Optics Express
Xiaojuan Zhang, Zhiguo Gui, Zhiwei Qiao, Yi Liu, Yu Shang
The current approaches to imaging the tissue blood flow index (BFI) from diffuse correlation tomography (DCT) data are either an analytical solution or a finite element method, both of which are unable to simultaneously account for the tissue heterogeneity and fully utilize the DCT data. In this study, a new imaging concept for DCT, namely NL-DCT, was created by us in which the medical images are combined with light Monte Carlo simulation to provide geometrical and heterogeneous information in tissue. Moreover, the DCT data at multiple delay time are fully utilized via iterative linear regression...
May 1, 2018: Biomedical Optics Express
Harnani Hassan, Sheila Jaidka, Vincent M Dwyer, Sijung Hu
One solution to the global challenge of increasing ocular disease is a cost-effective technique for rapid screening and assessment. Current ophthalmic imaging techniques, e.g. scanning and ocular blood flow systems, are expensive, complex to operate and utilize invasive contrast agents during assessment. The work presented here demonstrates a simple retinal imaging photoplethysmography (iPPG) system with the potential to provide screening, diagnosis, monitoring and assessment that is non-invasive, painless and radiationless...
May 1, 2018: Biomedical Optics Express
Myeong Jin Ju, Morgan Heisler, Arman Athwal, Marinko V Sarunic, Yifan Jian
We demonstrate the utility of a novel scanning method for optical coherence tomography angiography (OCTA). Although raster scanning is commonly used for OCTA imaging, a bidirectional approach would lessen the distortion caused by galvanometer-based scanners as sources continue to increase sweep rates. As shown, a unidirectional raster scan approach has a lower effective scanning time than bidirectional approaches; however, a strictly bidirectional approach causes contrast variation along the B-scan direction due to the non-uniform time interval between B-scans...
May 1, 2018: Biomedical Optics Express
Farhad Akhoundi, Yukun Qin, N Peyghambarian, Jennifer K Barton, Khanh Kieu
We present the design, implementation and performance analysis of a compact multi-photon endoscope based on a piezo electric scanning tube. A miniature objective lens with a long working distance and a high numerical aperture (≈ 0.5) is designed to provide a diffraction limited spot size. Furthermore, a 1700 nm wavelength femtosecond fiber laser is used as an excitation source to overcome the scattering of biological tissues and reduce water absorption. Therefore, the novel optical system along with the unique wavelength allows us to increase the imaging depth...
May 1, 2018: Biomedical Optics Express
Shu Wang, Huiping Du, Bingbing Lin, Chenxi Liao, Xiaoqin Zhu, Xingfu Wang, Hong Chen, Shuangmu Zhuo, Liwei Jiang, Lianhuang Li, Haohua Tu, Jianxin Chen
Ischemic stroke is a leading cause of death and permanent disability worldwide. Middle cerebral artery occlusion (MCAO) of variable duration times could be anticipated to result in varying degrees of injury that evolve spatially over time. Therefore, investigations following strokes require information concerning the spatiotemporal dimensions of the ischemic core as well as of perilesional areas. In the present study, multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was applied to image such pathophysiological events...
May 1, 2018: Biomedical Optics Express
Kriti Charan, Bo Li, Mengran Wang, Charles P Lin, Chris Xu
Deep tissue multiphoton imaging requires high peak power to enhance signal and low average power to prevent thermal damage. Both goals can be advantageously achieved through laser repetition rate tuning instead of simply adjusting the average power. We show that the ideal repetition rate for deep two-photon imaging in the mouse brain is between 1 and 10 MHz, and we present a fiber-based source with an arbitrarily tunable repetition rate within this range. The performance of the new source is compared to a mode-locked Ti:Sapphire (Ti:S) laser for in vivo imaging of mouse brain vasculature...
May 1, 2018: Biomedical Optics Express
Félix Fanjul-Vélez, Laura Arévalo-Díaz, José L Arce-Diego
Optical diffuse reflectance spectroscopy (DRS) has great potential in the study, diagnosis, and discrimination of biological tissues. Discrimination is based on massive measurements that conform training sets. These sets are then used to classify tissues according to the biomedical application. Classification accuracy depends strongly on the training dataset, which typically comes from different samples of the same class, and from different points of the same sample. The variability of these measurements is not usually considered and is assumed to be purely random, although it could greatly influence the results...
May 1, 2018: Biomedical Optics Express
Neda Haj-Hosseini, Johan C O Richter, Peter Milos, Martin Hallbeck, Karin Wårdell
A fiber optic probe was developed for guidance during stereotactic brain biopsy procedures to target tumor tissue and reduce the risk of hemorrhage. The probe was connected to a setup for the measurement of 5-aminolevulinic acid (5-ALA) induced fluorescence and microvascular blood flow. Along three stereotactic trajectories, fluorescence (n = 109) and laser Doppler flowmetry (LDF) (n = 144) measurements were done in millimeter increments. The recorded signals were compared to histopathology and radiology images...
May 1, 2018: Biomedical Optics Express
Maya Mizuno, Noriko Yaekashiwa, Soichi Watanabe
The absorption characteristics of the dermis were reviewed in the terahertz range from 0.2 to 2 THz. The absorption magnitude of the dermis was higher than that of the epidermis model owing to the inclusion of collagen fibers. The heat denaturation of the collagen and the decrease of water content in the dermis caused a decrease in the absorption magnitude of the dermis. We verified that the absorption magnitude of collagen sheets at 1 THz similarly decreased by nearly 43% upon the heat treatment at approximately 70° C...
May 1, 2018: Biomedical Optics Express
Mariia Borovkova, Mikhail Khodzitsky, Petr Demchenko, Olga Cherkasova, Alexey Popov, Igor Meglinski
We apply terahertz time-domain spectroscopy for the quantitative non-invasive assessment of the water content in biological samples, such as Carpinus caroliniana tree leaves and pork muscles. The developed experimental terahertz time-domain spectroscopy system operates both in transmission and reflection modes. The Landau-Looyenga-Lifshitz-based model is used for the calculation of the water concentration within the samples. The results of the water concentration measurements are compared with the results of the gravimetric measurements...
May 1, 2018: Biomedical Optics Express
Niels Møller Israelsen, Michael Maria, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Merete Haedersdal, Adrian Podoleanu, Ole Bang
Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised of the lower surface of a single cell layer in epidermis (the stratum basale) connected to an even thinner membrane (the basement membrane)...
May 1, 2018: Biomedical Optics Express
Zhenyue Chen, Xosé Luís Deán-Ben, Sven Gottschalk, Daniel Razansky
Fluorescent contrast agents are widely employed in biomedical research. While many studies have reported deep tissue imaging of fluorescent moieties using either fluorescence-based or absorption-based (optoacoustic) imaging systems, no systematic comparison has been performed regarding the actual performance of these imaging modalities in detecting deep-seated fluorescent agents. Herein, an integrated imager combining epi-fluorescence and volumetric optoacoustic imaging capabilities has been employed in order to evaluate image degradation with depth for several commonly-used near-infrared dyes in both modes...
May 1, 2018: Biomedical Optics Express
Honggu Choi, Zhe Li, Hao Sun, Dan Merrill, John Turek, Michael Childress, David Nolte
Biodynamic digital holography was used to obtain phenotypic profiles of canine non-Hodgkin B-cell lymphoma biopsies treated with standard-of-care chemotherapy. Biodynamic signatures from the living 3D tissues were extracted using fluctuation spectroscopy from intracellular Doppler light scattering in response to the molecular mechanisms of action of therapeutic drugs that modify a range of internal cellular motions. The standard-of-care to treat B-cell lymphoma in both humans and dogs is a combination CHOP therapy that consists of doxorubicin, prednisolone, cyclophosphamide and vincristine...
May 1, 2018: Biomedical Optics Express
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