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Journal of Biomedical Optics

Ben Lertsakdadet, Bruce Y Yang, Cody E Dunn, Adrien Ponticorvo, Christian Crouzet, Nicole Bernal, Anthony J Durkin, Bernard Choi
Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst)...
March 2018: Journal of Biomedical Optics
Toru Imai, Junhui Shi, Terence T W Wong, Lei Li, Liren Zhu, Lihong V Wang
Ultraviolet photoacoustic microscopy (UV-PAM) is a promising intraoperative tool for surgical margin assessment (SMA), one that can provide label-free histology-like images with high resolution. In this study, using a microlens array and a one-dimensional (1-D) array ultrasonic transducer, we developed a high-throughput multifocal UV-PAM (MF-UV-PAM). Our new system achieved a 1.6  ±  0.2  μm lateral resolution and produced images 40 times faster than the previously developed point-by-point scanning UV-PAM...
March 2018: Journal of Biomedical Optics
Ekaterina N Lazareva, Valery V Tuchin
This study is focused on the measurements of the refractive index of hemoglobin solutions in the visible/near-infrared (NIR) spectral range at room temperature for characteristic laser wavelengths: 480, 486, 546, 589, 644, 656, 680, 930, 1100, 1300, and 1550 nm. Measurements were performed using the multiwavelength Abbe refractometer. Aqua hemoglobin solutions of different concentrations obtained from human whole blood were investigated. The specific increment of refractive index on hemoglobin concentration and the Sellmeier coefficients were calculated...
March 2018: Journal of Biomedical Optics
Ali Hariri, Junxin Wang, Yeji Kim, Anamik Jhunjhunwala, Daniel L Chao, Jesse V Jokerst
Chorioretinal imaging has a crucial role for the patients with chorioretinal vascular diseases, such as neovascular age-related macular degeneration. Imaging oxygen gradients in the eye could better diagnose and treat ocular diseases. Here, we describe the use of photoacoustic ocular imaging (PAOI) in measuring chorioretinal oxygen saturation (CR  -  sO2) gradients in New Zealand white rabbits (n  =  5) with ocular ischemia. We observed good correlation (R2  =  0.98) between pulse oximetry and PAOI as a function of different oxygen percentages in inhaled air...
March 2018: Journal of Biomedical Optics
Masatsugu Niwayama
We quantitatively investigated the measurement sensitivity of spatially resolved spectroscopy (SRS) across six tissue models: cerebral tissue, a small animal brain, the forehead of a fetus, an adult brain, forearm muscle, and thigh muscle. The optical path length in the voxel of the model was analyzed using Monte Carlo simulations. It was found that the measurement sensitivity can be represented as the product of the change in the absorption coefficient and the difference in optical path length in two states with different source-detector distances...
March 2018: Journal of Biomedical Optics
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This publisher's note explains the change in citation data for 3 articles.
March 2018: Journal of Biomedical Optics
Hyung-Suk Lee, Sang-Kyeom Kim, Seok-Woo Park, Elbert de Josselin de Jong, Ho-Keun Kwon, Seung-Hwa Jeong, Baek-Il Kim
Occlusal discoloration due to staining frequently occurs on the pits and fissures of teeth. Noncariogenic discoloration (non-CD) refers to the attachment of staining chromogens to sound surfaces, whereas cariogenic discoloration (CD) represents the discoloration of porous structures due to bacterial metabolites and mineral loss from the enamel surface. This study evaluated whether it is possible to distinguish between non-CD and CD on stained occlusal surfaces with fluorescence assessed by the quantitative light-induced fluorescence (QLF) technology...
March 2018: Journal of Biomedical Optics
Andrea Filippi, Eleonora Dal Sasso, Laura Iop, Andrea Armani, Michele Gintoli, Marco Sandri, Gino Gerosa, Filippo Romanato, Giulia Borile
Label-free microscopy is a very powerful technique that can be applied to study samples with no need for exogenous fluorescent probes, keeping the main benefits of multiphoton microscopy, such as longer penetration depths and intrinsic optical sectioning while enabling serial multitechniques examinations on the same specimen. Among the many label-free microscopy methods, harmonic generation (HG) is one of the most intriguing methods due to its generally low photo-toxicity and relative ease of implementation...
March 2018: Journal of Biomedical Optics
Benjamin E Sherlock, Jenna N Harvestine, Debika Mitra, Anne Haudenschild, Jerry Hu, Kyriacos A Athanasiou, J Kent Leach, Laura Marcu
We investigate the use of a fiber-based, multispectral fluorescence lifetime imaging (FLIm) system to nondestructively monitor changes in mechanical properties of collagen hydrogels caused by controlled application of widely used cross-linking agents, glutaraldehyde (GTA) and ribose. Postcross-linking, fluorescence lifetime images are acquired prior to the hydrogels being processed by rheological or tensile testing to directly probe gel mechanical properties. To preserve the sterility of the ribose-treated gels, FLIm is performed inside a biosafety cabinet (BSC)...
March 2018: Journal of Biomedical Optics
Brian C Wilson, Michael Jermyn, Frederic Leblond
Medical devices face many hurdles before they enter routine clinical practice to address unmet clinical needs. This is also the case for biomedical optical spectroscopy and imaging systems that are used here to illustrate the opportunities and challenges involved. Following initial concept, stages in clinical translation include instrument development, preclinical testing, clinical prototyping, clinical trials, prototype-to-product conversion, regulatory approval, commercialization, and finally clinical adoption and dissemination, all in the face of potentially competing technologies...
March 2018: Journal of Biomedical Optics
Laura Remón, Damian Siedlecki, Iulen Cabeza-Gil, Begoña Calvo
Intraocular lenses (IOLs) are used in the cataract treatment for surgical replacement of the opacified crystalline lens. Before being implanted they have to pass the strict quality control to guarantee a good biomechanical stability inside the capsular bag, avoiding the rotation, and to provide a good optical quality. The goal of this study was to investigate the influence of the material and haptic design on the behavior of the IOLs under dynamic compression condition. For this purpose, the strain-stress characteristics of the hydrophobic and hydrophilic materials were estimated experimentally...
March 2018: Journal of Biomedical Optics
Hequn Wang, Thomas Shyr, Michael J Fevola, Gabriela Oana Cula, Georgios N Stamatas
Two-photon fluorescence (TPF) and second harmonic generation (SHG) microscopy provide direct visualization of the skin dermal fibers in vivo. A typical method for analyzing TPF/SHG images involves averaging the image intensity and therefore disregarding the spatial distribution information. The goal of this study is to develop an algorithm to document age-related effects of the dermal matrix. TPF and SHG images were acquired from the upper inner arm, volar forearm, and cheek of female volunteers of two age groups: 20 to 30 and 60 to 80 years of age...
March 2018: Journal of Biomedical Optics
Elaine M Wells-Gray, Stacey S Choi, Robert J Zawadzki, Susanna C Finn, Cherry Greiner, John S Werner, Nathan Doble
We have designed and implemented a dual-mode adaptive optics (AO) imaging system that combines spectral domain optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) for in vivo imaging of the human retina. The system simultaneously acquires SLO frames and OCT B-scans at 60 Hz with an OCT volume acquisition time of 4.2 s. Transverse eye motion measured from the SLO is used to register the OCT B-scans to generate three-dimensional (3-D) volumes. Key optical design considerations include: minimizing system aberrations through the use of off-axis relay telescopes, conjugate pupil plane requirements, and the use of dichroic beam splitters to separate and recombine the OCT and SLO beams around the nonshared horizontal scanning mirrors...
March 2018: Journal of Biomedical Optics
Xinyu Li, Shanshan Liang, Jun Zhang
Saturation artifacts that are commonly observed in endoscopic swept-source optical coherence tomography (SSOCT) images cause image degradation and loss of image information. We present work on the correction of saturation effects in endoscopic SSOCT imaging. This method utilizes a broadband power divider with excellent pick-off flatness to divide the detected interference signal into the two channels of an analog-to-digital converter. Based on the precise calibration of the splitting ratio between the two channels, the maximum measurable signal power of the system was drastically increased by using the low level signal in one channel to correct the saturated signal in the other channel...
March 2018: Journal of Biomedical Optics
Julia Walther, Christian Schnabel, Florian Tetschke, Tobias Rosenauer, Jonas Golde, Nadja Ebert, Michael Baumann, Christian Hannig, Edmund Koch
The common way to diagnose hard and soft tissue irregularities in the oral cavity is initially the visual inspection by an experienced dentist followed by further medical examinations, such as radiological imaging and/or histopathological investigation. For the diagnosis of oral hard and soft tissues, the detection of early transformations is mostly hampered by poor visual access, low specificity of the diagnosis techniques, and/or limited feasibility of frequent screenings. Therefore, optical noninvasive diagnosis of oral tissue is promising to improve the accuracy of oral screening...
March 2018: Journal of Biomedical Optics
Hamed Abbasi, Georg Rauter, Raphael Guzman, Philippe C Cattin, Azhar Zam
In laserosteotomy, it is vital to avoid thermal damage of the surrounding tissue, such as carbonization, since carbonization does not only deteriorate the ablation efficiency but also prolongs the healing process. The state-of-the-art method to avoid carbonization is irrigation systems; however, it is difficult to determine the desired flow rate of the air and cooling water based on previous experiments without online monitoring of the bone surface. Lack of such feedback during the ablation process can cause carbonization in case of a possible error in the irrigation system or slow down the cutting process when irrigating with too much cooling water...
March 2018: Journal of Biomedical Optics
Clara Mestre, Josselin Gautier, Jaume Pujol
A set of methods in terms of both image processing and gaze estimation for accurate eye tracking is proposed. The eye-tracker used in this study relies on the dark-pupil method with up to 12 corneal reflections and offers an unprecedented high resolution imaging of the pupil and the cornea. The potential benefits of a higher number of glints and their optimum arrangement are analyzed considering distinct light sources configurations with 12, 8, 6, 4, and 2 corneal reflections. Moreover, a normalization factor of the pupil-glint vector is proposed for each configuration...
March 2018: Journal of Biomedical Optics
Ana Batista, Hans Georg Breunig, Aisada König, Andreas Schindele, Tobias Hager, Berthold Seitz, Karsten König
The diagnosis of corneal diseases may be improved by monitoring the metabolism of cells and the structural organization of the stroma using two-photon imaging (TPI). We used TPI to assess the differences between nonpathological (NP) human corneas and corneas diagnosed with either keratoconus, Acanthamoeba keratitis, or stromal corneal scars. Images were acquired using a custom-built five-dimensional laser-scanning microscope with a broadband sub-15 femtosecond near-infrared pulsed excitation laser and a 16-channel photomultiplier tube detector in combination with a time-correlated single photon counting module...
March 2018: Journal of Biomedical Optics
Victoria Zherdeva, Natalia I Kazachkina, Vladislav Shcheslavskiy, Alexander P Savitsky
Caspase-3 is known for its role in apoptosis and programmed cell death regulation. We detected caspase-3 activation in vivo in tumor xenografts via shift of mean fluorescence lifetimes of a caspase-3 sensor. We used the genetically encoded sensor TR23K based on the red fluorescent protein TagRFP and chromoprotein KFP linked by 23 amino acid residues (TagRFP-23-KFP) containing a specific caspase cleavage DEVD motif to monitor the activity of caspase-3 in tumor xenografts by means of fluorescence lifetime imaging-Forster resonance energy transfer...
March 2018: Journal of Biomedical Optics
Wenhao Li, Jingming Liu, Zhenting Zhang
Marginal gap (MG) was the most important factor to evaluate the success of crowns. The study was to assess the MG of lithium disilicate glass ceramic crowns with spectral domain optical coherence tomography (OCT) and stereomicroscopy in vitro, and to provide evidence to measure the MG with OCT. Consistency was observed between OCT and stereomicroscopy to measure the MG after cementation. There was no significant difference between the MG of lithium disilicate glass ceramic crowns using OCT and stereomicroscopy (OCT 59...
March 2018: Journal of Biomedical Optics
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