342 results found
Avila-Rencoret FB, Mylonas GP, Elson DS, 2018, Robotic wide-field optical biopsy endoscopy
© OSA 2018. This paper describes a novel robotic framework for wide-field optical biopsy endoscopy, characterizes in vitro its spatial and spectral resolution, real time hyperspectral tissue classification, and demonstrates its feasibility on fresh porcine cadaveric colon.
Deng L, Yan JD, Elson DS, et al., 2018, Characterization of an imaging multimode optical fiber using a digital micro-mirror device based single-beam system, OPTICS EXPRESS, Vol: 26, Pages: 18436-18447, ISSN: 1094-4087
Lin J, Clancy NT, Qi J, et al., 2018, Dual-modality endoscopic probe for tissue surface shape reconstruction and hyperspectral imaging enabled by deep neural networks, MEDICAL IMAGE ANALYSIS, Vol: 48, Pages: 162-176, ISSN: 1361-8415
Lin J, Walsted ES, Backer V, et al., 2018, Quantification and Analysis of Laryngeal Closure from Endoscopic Videos, IEEE Transactions on Biomedical Engineering, ISSN: 0018-9294
IEEE Objective: At present, there are no objective techniques to quantify and describe laryngeal obstruction, and the reproducibility of subjective manual quantification methods is insufficient, resulting in diagnostic inaccuracy and a poor signal-to-noise ratio in medical research. In this work, a workflow is proposed to quantify laryngeal movements from laryngoscopic videos, to facilitate the diagnosis procedure. Methods: The proposed method analyses laryngoscopic videos, and delineates glottic opening, vocal folds, and supraglottic structures, using a convolutional neural networks (CNNs) based algorithm. The segmentation is divided into two steps: A bounding box which indicates the region of interest (RoI) is found, followed by segmentation using fully convolutional networks (FCNs). The segmentation results are statistically quantified along the temporal dimension and processed using singular spectrum analysis (SSA), to extract clear objective information that can be used by the clinicians in diagnosis. Results: The segmentation was validated on 400 images from 20 videos acquired using different endoscopic systems from different patients. The results indicated significant improvements over using FCN only in terms of both processing speed (16 FPS vs. 8 FPS) and segmentation result statistics. Five clinical cases on patients have also been provided to showcase the quantitative analysis results using the proposed method. Conclusion: The proposed method guarantees a robust and fast processing of laryngoscopic videos. Measurements of glottic angles and supraglottic index showed distinctive patterns in the provided clinical cases. Significance: The proposed automated and objective method extracts important temporal laryngeal movement information, which can be used to aid laryngeal closure diagnosis.
Qi J, He H, Lin J, et al., 2018, Assessment of tissue polarimetric properties using Stokes polarimetric imaging with circularly polarized illumination, JOURNAL OF BIOPHOTONICS, Vol: 11, ISSN: 1864-063X
Saso S, Clancy NT, Jones BP, et al., 2018, Use of biomedical photonics in gynecological surgery: a uterine transplantation model, FUTURE SCIENCE OA, Vol: 4, ISSN: 2056-5623
Saso S, Tziraki M, Clancy NT, et al., 2018, Use of Laser Speckle Contrast Analysis during pelvic surgery in a uterine transplantation model., Future Sci OA, Vol: 4, ISSN: 2056-5623
Aim: Uterine transplantation (UTx) is proposed for treatment of uterine factor infertility. Our aim was to assess whether Endoscopic Laser Speckle Contrast Analysis (eLASCA) could evaluate pelvic blood flow at anastomotic sites required for sheep and rabbit UTx. Results/methodology: eLASCA detected blood flow in rabbit UTx #7 and #9. In sheep UTx #2, #3 and #5, the results allowed us to conclude that blood flow was present in the uterine graft following transplantation; and post-UTx, the animal had heart and respiratory rates, and oxygen saturation compatible with a normal hemodynamic status. Conclusion: These preliminary results establish the potential of Laser Speckle Contrast Analysis as noncontact and real-time tool for observation of spatially-resolved blood flow from which other parameters can be derived.
Song L, Wang X, Zhang R, et al., 2018, Improving temporal resolution and speed sensitivity of laser speckle contrast analysis imaging based on noise reduction with an anisotropic diffusion filter, JOURNAL OF OPTICS, Vol: 20, ISSN: 2040-8978
Wirkert SJ, Vemuri AS, Kenngott HG, et al., 2018, Physiological parameter estimation from multispectral images unleashed, ISSN: 1431-472X
© Springer-Verlag GmbH Deutschland 2018. Multispectral imaging in laparoscopy can provide tissue reflectance measurements for each point in the image at multiple wavelengths of light. These reflectances encode information on important physiological parameters not visible to the naked eye. Fast decoding of the data during surgery, however, remains challenging.
Zhao T, Deng L, Wang W, et al., 2018, Bayes' theorem-based binary algorithm for fast reference-less calibration of a multimode fiber, OPTICS EXPRESS, Vol: 26, Pages: 20368-20378, ISSN: 1094-4087
Clancy NT, Elson DS, Teare J, 2017, Hyperspectral imaging of colonic polyps in vivo (Conference Presentation), Conference on Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XV, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Dong Y, Qi J, He H, et al., 2017, Quantitatively characterizing the microstructural features of breast ductal carcinoma tissues in different progression stages by Mueller matrix microscope, BIOMEDICAL OPTICS EXPRESS, Vol: 8, Pages: 3643-3655, ISSN: 2156-7085
Elson DS, 2017, Polarization-resolved endoscopy for image-guided surgery
Harris-Birtill D, Singh M, Zhou Y, et al., 2017, Gold nanorod reshaping in vitro and in vivo using a continuous wave laser., PLoS ONE, Vol: 12, ISSN: 1932-6203
Gold nanorods (GNRs) are increasingly being investigated for cancer theranostics as they possess features which lend themselves in equal measures as contrast agents and catalysts for photothermal therapy. Their optical absorption spectral peak wavelength is determined by their size and shape. Photothermal therapy using GNRs is typically established using near infrared light as this allows sufficient penetration into the tumour matrix. Continuous wave (CW) lasers are the most commonly applied source of near infrared irradiation on GNRs for tumour photothermal therapy. It is perceived that large tumours may require fractionated or prolonged irradiation. However the true efficacy of repeated or protracted CW irradiation on tumour sites using the original sample of GNRs remains unclear. In this study spectroscopy and transmission electron microscopy are used to demonstrate that GNRs reshape both in vitro and in vivo after CW irradiation, which reduces their absorption efficiency. These changes were sustained throughout and beyond the initial period of irradiation, resulting from a spectral blue-shift and a considerable diminution in the absorption peak of GNRs. Solid subcutaneous tumours in immunodeficient BALB/c mice were subjected to GNRs and analysed with electron microscopy pre- and post-CW laser irradiation. This phenomenon of thermally induced GNR reshaping can occur at relatively low bulk temperatures, well below the bulk melting point of gold. Photoacoustic monitoring of GNR reshaping is also evaluated as a potential clinical aid to determine GNR absorption and reshaping during photothermal therapy. Aggregation of particles was coincidentally observed following CW irradiation, which would further diminish the subsequent optical absorption capacity of irradiated GNRs. It is thus established that sequential or prolonged applications of CW laser will not confer any additional photothermal effect on tumours due to significant attenuations in the peak optical absorpt
Janatka M, Ramdoo KS, Tatla T, et al., 2017, Examining in vivo Tympanic Membrane Mobility Using Smart Phone Video-Otoscopy and Phase-based Eulerian Video Magnification, Conference on Medical Imaging - Computer-Aided Diagnosis, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Jones G, Clancy NT, Du X, et al., 2017, Fast estimation of haemoglobin concentration in tissue via wavelet decomposition, Pages: 100-108, ISSN: 0302-9743
© Springer International Publishing AG 2017. Tissue oxygenation and perfusion can be an indicator for organ viability during minimally invasive surgery, for example allowing real-time assessment of tissue perfusion and oxygen saturation. Multispectral imaging is an optical modality that can inspect tissue perfusion in wide field images without contact. In this paper, we present a novel, fast method for using RGB images for MSI, which while limiting the spectral resolution of the modality allows normal laparoscopic systems to be used. We exploit the discrete Haar decomposition to separate individual video frames into low pass and directional coefficients and we utilise a different multispectral estimation technique on each. The increase in speed is achieved by using fast Tikhonov regularisation on the directional coefficients and more accurate Bayesian estimation on the low pass component. The pipeline is implemented using a graphics processing unit (GPU) architecture and achieves a frame rate of approximately 15 Hz. We validate the method on animal models and on human data captured using a da Vinci stereo laparoscope.
Jones G, Clancy NT, Helo Y, et al., 2017, Bayesian Estimation of Intrinsic Tissue Oxygenation and Perfusion From RGB Images, IEEE TRANSACTIONS ON MEDICAL IMAGING, Vol: 36, Pages: 1491-1501, ISSN: 0278-0062
Lin J, Clancy NT, Hu Y, et al., 2017, Endoscopic depth measurement and super-spectral-resolution imaging, Pages: 39-47, ISSN: 0302-9743
© Springer International Publishing AG 2017. Intra-operative measurements of tissue shape and multi/hyperspectral information have the potential to provide surgical guidance and decision making support. We report an optical probe based system to combine sparse hyperspectral measurements and spectrally-encoded structured lighting (SL) for surface measurements. The system provides informative signals for navigation with a surgical interface. By rapidly switching between SL and white light (WL) modes, SL information is combined with structure-from-motion (SfM) from white light images, based on SURF feature detection and Lucas-Kanade (LK) optical flow to provide quasi-dense surface shape reconstruction with known scale in real-time. Furthermore, “super-spectral-resolution” was realized, whereby the RGB images and sparse hyperspectral data were integrated to recover dense pixel-level hyperspectral stacks, by using convolutional neural networks to upscale the wavelength dimension. Validation and demonstration of this system is reported on ex vivo/in vivo animal/human experiments.
Ong ZY, Chen S, Nabavi E, et al., 2017, Multibranched Gold Nanoparticles with Intrinsic LAT-1 Targeting Capabilities for Selective Photothermal Therapy of Breast Cancer, ACS APPLIED MATERIALS & INTERFACES, Vol: 9, Pages: 39259-39270, ISSN: 1944-8244
Qi J, Elson DS, 2017, Mueller polarimetric imaging for surgical and diagnostic applications: a review, JOURNAL OF BIOPHOTONICS, Vol: 10, Pages: 950-982, ISSN: 1864-063X
Qi J, He C, Elson DS, 2017, Real time complete Stokes polarimetric imager based on a linear polarizer array camera for tissue polarimetric imaging, BIOMEDICAL OPTICS EXPRESS, Vol: 8, Pages: 4933-4946, ISSN: 2156-7085
Qi J, He H, Ma H, et al., 2017, Extended polar decomposition method of Mueller matrices for turbid media in reflection geometry, OPTICS LETTERS, Vol: 42, Pages: 4048-4051, ISSN: 0146-9592
Qi J, Nabavi E, Hu Y, et al., 2017, A light-weight near infrared fluorescence endoscope based on a single color camera: a proof-of-concept study, Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Publisher: IEEE
Shah PL, Kemp SV, Newton RC, et al., 2017, Clinical Correlation between Real-Time Endocytoscopy, Confocal Endomicroscopy, and Histopathology in the Central Airways, RESPIRATION, Vol: 93, Pages: 51-57, ISSN: 0025-7931
Tonutti M, Elson DS, Yang G-Z, et al., 2017, The role of technology in minimally invasive surgery: state of the art, recent developments and future directions, POSTGRADUATE MEDICAL JOURNAL, Vol: 93, Pages: 159-167, ISSN: 0032-5473
Wirkert SJ, Vemuri AS, Kenngott HG, et al., 2017, Physiological parameter estimation from multispectral images unleashed, Pages: 134-141, ISSN: 0302-9743
© Springer International Publishing AG 2017. Multispectral imaging in laparoscopy can provide tissue reflectance measurements for each point in the image at multiple wavelengths of light. These reflectances encode information on important physiological parameters not visible to the naked eye. Fast decoding of the data during surgery, however, remains challenging. While model-based methods suffer from inaccurate base assumptions, a major bottleneck related to competing machine learning-based solutions is the lack of labelled training data. In this paper, we address this issue with the first transfer learning-based method to physiological parameter estimation from multispectral images. It relies on a highly generic tissue model that aims to capture the full range of optical tissue parameters that can potentially be observed in vivo. Adaptation of the model to a specific clinical application based on unlabelled in vivo data is achieved using a new concept of domain adaptation that explicitly addresses the high variance often introduced by conventional covariance-shift correction methods. According to comprehensive in silico and in vivo experiments our approach enables accurate parameter estimation for various tissue types without the need for incorporating specific prior knowledge on optical properties and could thus pave the way for many exciting applications in multispectral laparoscopy.
Zhang Y, Wirkert SJ, Iszatt J, et al., 2017, Tissue classification for laparoscopic image understanding based on multispectral texture analysis, JOURNAL OF MEDICAL IMAGING, Vol: 4, ISSN: 2329-4302
Clancy NT, Saso S, Stoyanov D, et al., 2016, Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep, JOURNAL OF BIOMEDICAL OPTICS, Vol: 21, ISSN: 1083-3668
Clancy NT, Teare J, Hanna GB, et al., 2016, Flexible multimode endoscope for tissue reflectance and autofluorescence hyperspectral imaging
© OSA 2016. A dual reflectance and autofluorescence spectral imaging probe compatible with the biopsy channels of standard flexible endoscopes is demonstrated. Spatially-resolved haemoglobin and autofluorescent signals from porcine bowel were obtained in vivo.
© OSA 2016. We present an in vivo study of endoscopic fluorescence image-guided photothermal therapy of human oesophageal adenocarcinoma in a murine xenograft model, using intratumoural or intravenous gold nanorods functionalised with Cy5.5 and EGFR.
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