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Biomedical Optics Express

Shaohua Pi, Acner Camino, Xiang Wei, Joseph Simonett, William Cepurna, David Huang, John C Morrison, Yali Jia
Visible light optical coherence tomography (vis-OCT) is an emerging label-free and high-resolution 3-dimensional imaging technique that can provide retinal oximetry, angiography, and flowmetry in one modality. In this paper, we studied the organization of the arterial and venous retinal circulation in rats using vis-OCT. Arterioles were found predominantly in the superficial vascular plexus whereas veins tended to drain capillaries from the deep capillary plexus. After that, we determined the oxygen metabolic rate supported by retinal microcirculation by combining retinal vessel oxygen saturation and blood flow measurements...
November 1, 2018: Biomedical Optics Express
Qianqian Wang, Geer Teng, Xiaolei Qiao, Yu Zhao, Jinglin Kong, Liqiang Dong, Xutai Cui
The correct classification of pathogenic bacteria is significant for clinical diagnosis and treatment. Compared with the use of whole spectral data, using feature lines as the inputs of the classification model can improve the correct classification rate (CCR) and reduce the analyzing time. In order to select feature lines, we need to investigate the contribution to the CCR of each spectral line. In this paper, two algorithms, important weights based on principal component analysis (IW-PCA) and random forests (RF), were proposed to evaluate the importance of spectra lines...
November 1, 2018: Biomedical Optics Express
L Herve, O Cioni, P Blandin, F Navarro, M Menneteau, T Bordy, S Morales, C Allier
Lens-free microscopy multispectral acquisitions are processed with an inverse problem approach: a multispectral total variation criterion is defined and minimized with the conjugate gradients method. Reconstruction results show that the method is efficient to recover the phase image of densely packed cells.
November 1, 2018: Biomedical Optics Express
A A Zhikhoreva, A V Belashov, V G Bespalov, A L Semenov, I V Semenova, G V Tochilnikov, N T Zhilinskaya, O S Vasyutinskii
The development of new express methods for the analysis of the efficacy of anti-cancer therapy on the cellular level is highly desirable for the analysis of chemotherapeutic agent performance. In this paper we suggest the use of parameters of cell morphology determined by holographic microscopy and tomography for the effective label free quantitative analysis of cell viability under antitumor chemotherapy and thus of cytostatic agent efficacy. As shown, measured phase shifts and cell morphology change dramatically as a result of chemotherapy and depend strongly on the cell type and agent applied...
November 1, 2018: Biomedical Optics Express
Yizhi Liang, Jin-Wei Liu, Long Jin, Bai-Ou Guan, Lidai Wang
Optical-resolution photoacoustic microscopy (OR-PAM) images biological tissue with sub-cellular resolution and optical absorption contrast. OR-PAM is limited by the tradeoff among imaging speed, field of view, and sensitivity. In this work, we present an OR-PAM technique based on an unfocused side-looking fiber optic ultrasound (FOUS) sensor, which achieves high imaging speed, large field of view, and good sensitivity for in vivo imaging. The FOUS sensor is developed based on a dual-polarized fiber laser and read out with real-time frequency demodulation...
November 1, 2018: Biomedical Optics Express
Etsuko Ohmae, Nobuko Yoshizawa, Kenji Yoshimoto, Maho Hayashi, Hiroko Wada, Tetsuya Mimura, Hiroaki Suzuki, Shu Homma, Norihiro Suzuki, Hiroyuki Ogura, Hatsuko Nasu, Harumi Sakahara, Yutaka Yamashita, Yukio Ueda
We introduced a method for producing solid phantoms with various water-to-lipid ratios that can simulate the absorption, and to some extent the scattering characteristics of human breast tissue. We also achieved phantom stability for a minimum of one month by solidifying the emulsion phantoms. The characteristics of the phantoms were evaluated using the six-wavelength time-domain diffuse optical spectroscopy (TD-DOS) system we developed to measure water and lipid contents and hemoglobin concentration. The TD-DOS measurements were validated with a magnetic resonance imaging system...
November 1, 2018: Biomedical Optics Express
Sorin Viorel Parasca, Mihaela Antonina Calin, Dragos Manea, Sorin Miclos, Roxana Savastru
Burn depth objective classification is of paramount importance for decision making and treatment. Despite the wide variety of burn depth assessment methods tested so far, none of them have gained wide clinical application. Here, we introduce a new approach for burn depth assessment based on hyperspectral imaging combined with a spectral index-based technique that exploits specific spectral bands to map skin areas with different burn degrees. The spectral index amplifies the contrast between normal skin and areas with different degrees of burn, taking advantage of the differences in spectral amplitudes that occur as a result of the morphological and physiological changes occurring in burned skin...
November 1, 2018: Biomedical Optics Express
Jason Kugelman, David Alonso-Caneiro, Scott A Read, Stephen J Vincent, Michael J Collins
The manual segmentation of individual retinal layers within optical coherence tomography (OCT) images is a time-consuming task and is prone to errors. The investigation into automatic segmentation methods that are both efficient and accurate has seen a variety of methods proposed. In particular, recent machine learning approaches have focused on the use of convolutional neural networks (CNNs). Traditionally applied to sequential data, recurrent neural networks (RNNs) have recently demonstrated success in the area of image analysis, primarily due to their usefulness to extract temporal features from sequences of images or volumetric data...
November 1, 2018: Biomedical Optics Express
Lingyu Hong, Hao Li, Haw Yang, Kaushik Sengupta
The ultra-miniaturization of massively multiplexed fluorescence-based bio-molecular sensing systems for proteins and nucleic acids into a chip-scale form, small enough to fit inside a pill (∼ 0.1cm3 ), can revolutionize sensing modalities in-vitro and in-vivo. Prior miniaturization techniques have been limited to focusing on traditional optical components (multiple filter sets, lenses, photo-detectors, etc.) arranged in new packaging systems. Here, we report a method that eliminates all external optics and miniaturizes an entire multiplexed fluorescence system into a 2 × 1 mm2 chip through co-integration for the first time of massively scalable nano-plasmonic multi-functional optical elements and electronic processing circuitry realized in an industry standard complementary-metal-oxide semiconductor (CMOS) foundry process with absolutely 'no change' in fabrication or processing...
November 1, 2018: Biomedical Optics Express
Eashani Sathialingam, Seung Yup Lee, Bharat Sanders, Jaekeun Park, Courtney E McCracken, Leah Bryan, Erin M Buckley
Diffuse correlation spectroscopy (DCS) has shown promise as a means to non-invasively measure cerebral blood flow in small animal models. Here, we characterize the validity of DCS at small source-detector reflectance separations needed for small animal measurements. Through Monte Carlo simulations and liquid phantom experiments, we show that DCS error increases as separation decreases, although error remains below 12% for separations > 0.2 cm. In mice, DCS measures of cerebral blood flow have excellent intra-user repeatability and strongly correlate with MRI measures of blood flow (R = 0...
November 1, 2018: Biomedical Optics Express
Gyeong Bok Jung, Jeong-Eun Huh, Hyo-Jung Lee, Dohyun Kim, Gi-Ja Lee, Hun-Kuk Park, Jae-Dong Lee
We demonstrated the apoptotic effect of bee venom (BV) on human MDA-MB-231 breast cancer cells using Raman spectroscopy and principal component analysis (PCA). Biochemical changes in cancer cells were monitored following BV treatment; the results for different concentrations and treatment durations differed markedly. Significantly decreased Raman vibrations for DNA and proteins were observed for cells treated with 3.0 µg/mL BV for 48 h compared with those of control cells. These results suggest denaturation and degradation of proteins and DNA fragmentation (all cell death-related processes)...
November 1, 2018: Biomedical Optics Express
Meredith Kupinski, Matthieu Boffety, François Goudail, Razvigor Ossikovski, Angelo Pierangelo, Jean Rehbinder, Jérémy Vizet, Tatiana Novikova
Prior work demonstrated significant contrast in visible wavelength Mueller matrix images for healthy and pre-cancerous regions of excised cervical tissue. This work demonstrates post-processing compressions of the full Mueller matrix that preserve detection performance. The purpose of this post-processing is to understand polarimetric measurement utility for computing mathematical observers and designing future imaging protocols. The detection performance of the full Mueller matrix, and both linear and non-linear parameters of the Mueller matrix will be compared...
November 1, 2018: Biomedical Optics Express
Anthony M D Lee, Calum MacAulay, Pierre Lane
We present a new micromotor catheter implementation of dual-beam manually-actuated distortion-corrected imaging (DMDI). The new catheter called a depth-multiplexed dual-beam micromotor catheter, or mDBMC, maintains the primary advantage of unlimited field-of-view distortion-corrected imaging along the catheter axis. The mDBMC uses a polarization beam splitter and cube mirror to create two beams that scan circularly with approximately constant separation at the catheter surface. This arrangement also multiplexes both imaging channels into a single optical coherence tomography channel by offsetting them in depth, requiring half the data bandwidth compared to previous DMDI demonstrations that used two parallel image acquisition systems...
November 1, 2018: Biomedical Optics Express
Mazen A Juratli, Yulian A Menyaev, Mustafa Sarimollaoglu, Alexander V Melerzanov, Dmitry A Nedosekin, William C Culp, James Y Suen, Ekaterina I Galanzha, Vladimir P Zharov
Blood clotting is a serious clinical complication of many medical procedures and disorders including surgery, catheterization, transplantation, extracorporeal circuits, infections, and cancer. This complication leads to high patient morbidity and mortality due to clot-induced pulmonary embolism, stroke, and in some cases heart attack. Despite the clear medical significance, little progress has been made in developing the methods for detection of circulating blood clots (CBCs), also called emboli. We recently demonstrated the application of in vivo photoacoustic (PA) flow cytometry (PAFC) with unfocused ultrasound transducers for detection of CBCs in small vessels in a mouse model...
November 1, 2018: Biomedical Optics Express
Yi Xue, Kalen P Berry, Josiah R Boivin, Dushan Wadduwage, Elly Nedivi, Peter T C So
Line-scanning temporal focusing microscopy (LineTFM) is capable of imaging biological samples more than 10 times faster than two-photon laser point-scanning microscopy (TPLSM), while achieving nearly the same lateral and axial spatial resolution. However, the image contrast taken by LineTFM is lower than that by TPLSM because LineTFM is severely influenced by biological tissue scattering. To reject the scattered photons, we implemented LineTFM using both structured illumination and uniform illumination combined with the HiLo post-processing algorithm, called HiLL microscopy (HiLo-Line-scanning temporal focusing microscopy)...
November 1, 2018: Biomedical Optics Express
Masaki Yumoto, Norihito Saito, Taichen Lin, Rie Kawamura, Akira Aoki, Yuichi Izumi, Satoshi Wada
We have developed a mid-infrared (mid-IR) tunable Cr:CdSe laser with nanosecond pulse operation. A broad tuning range from 2.25 to 3.08 µm and an output energy exceeding 4 mJ at 2.64 μm were demonstrated. The maximum energy conversion for absorbed energy reached 35% when the pump fluence was 2.1 J/cm2 . We showed that Cr:CdSe is an attractive laser material for obtaining high-energy pulses in the mid-IR region and that the Cr:CdSe laser has high potential for laser biomaterial processing.
November 1, 2018: Biomedical Optics Express
Svetlana Basov, Amit Milstein, Erez Sulimani, Max Platkov, Eli Peretz, Marcel Rattunde, Joachim Wagner, Uri Netz, Abraham Katzir, Ilana Nisky
Fast and reliable incision closure is critical in any surgical intervention. Common solutions are sutures and clips or adhesives, but they all present difficulties. These difficulties are especially pronounced in classical and robot-assisted minimally-invasive interventions. Laser soldering methods present a promising alternative, but their reproducibility is limited. We present a system that combines a previously reported laser soldering system with a robotic system, and demonstrate its feasibility on the incision-closure of ex-vivo mice skins...
November 1, 2018: Biomedical Optics Express
Dene Ringuette, Jacob Nauenberg, Philippe P Monnier, Peter L Carlen, Ofer Levi
Single-frame blood flow maps from laser speckle contrast imaging (LSCI) contain high spatiotemporal variation that obscures high spatial-frequency vascular features, making precise image registration for signal amplification challenging. In this work, novel bivariate standardized moment filters (BSMFs) were used to provide stable measures of vessel edge location, permitting more robust LSCI registration. Relatedly, BSMFs enabled the stable reconstruction of vessel edges from sparsely distributed blood flow map outliers, which were found to retain most of the temporal dynamics...
November 1, 2018: Biomedical Optics Express
J W Hoi, H K Kim, C J Fong, L Zweck, A H Hielscher
A novel multi-view non-contact dynamic diffuse optical tomographic imaging system for the clinical evaluation of vasculature in the lower extremities is presented. The system design and implementation are described in detail, including methods for simultaneously obtaining and reconstructing diffusely reflected and transmitted light using a system of mirrors and a single CCD camera. The system and its performance using numeric simulations and optical phantoms. Measurements of a healthy foot in vivo demonstrates the potential of the system in assessing perfusion within the foot...
November 1, 2018: Biomedical Optics Express
Mariela C Aguilar, Alex Gonzalez, Cornelis Rowaan, Carolina de Freitas, Karam A Alawa, Heather Durkee, William J Feuer, Fabrice Manns, Shihab S Asfour, Byron L Lam, Jean-Marie A Parel
The Ocular Photosensitivity Analyzer (OPA), a new automated instrument to quantify the visual photosensitivity thresholds (VPT) in healthy and light sensitive subjects, is described. The OPA generates light stimuli of varying intensities utilizing unequal ascending and descending steps to yield the VPT. The performance of the OPA was evaluated in healthy subjects, as well as light sensitive subjects with achromatopsia or traumatic brain injury (TBI). VPT in healthy, achromatopsia, and TBI subjects were 3.2 ± 0...
November 1, 2018: Biomedical Optics Express
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