1. Articles from Stephen A. Boppart

    1-24 of 165 1 2 3 4 5 6 7 »
    1. Statistical evaluation of reader variability in assessing the diagnostic performance of optical coherence tomography

      Statistical evaluation of reader variability in assessing the diagnostic performance of optical coherence tomography

      Significance: Optical coherence tomography (OCT) is widely used as a potential diagnostic tool for a variety of diseases including various types of cancer. However, sensitivity and specificity analyses of OCT in different cancers yield results varying from 11% to 100%. Hence, there is a need for more detailed statistical analysis of blinded reader studies. Aim: Extensive statistical analysis is performed on results from a blinded study involving OCT of breast tumor margins to assess the impact of reader variability on sensitivity and specificity. Approach: Five readers with varying levels of experience reading OCT images assessed 50 OCT images of breast ...

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    2. The feasibility and utility of optical coherence tomography directed histopathology for surgical margin assessment of canine mast cell tumors

      The feasibility and utility of optical coherence tomography directed histopathology for surgical margin assessment of canine mast cell tumors

      Histopathologic surgical margin assessment in veterinary patients is an imprecise science with assessment limited to a small proportion of the surgical margin due to time and finances. Incomplete excision of canine mast cell tumors (MCTs) alters treatment recommendations and prognosis. Optical coherence tomography (OCT) is a novel imaging modality that has been reported in a single veterinary study for surgical margin assessment. Twenty‐five dogs with 34 MCTs were enrolled in a prospective pilot‐study to assess the imaging characteristics of canine MCTs with OCT and to evaluate the feasibility and utility of OCT‐guided histopathology. All dogs underwent routine ...

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    3. Automated fast computational adaptive optics for optical coherence tomography based on a stochastic parallel gradient descent algorithm

      Automated fast computational adaptive optics for optical coherence tomography based on a stochastic parallel gradient descent algorithm

      The transverse resolution of optical coherence tomography is decreased by aberrations introduced from optical components and the tested samples. In this paper, an automated fast computational aberration correction method based on a stochastic parallel gradient descent (SPGD) algorithm is proposed for aberration-corrected imaging without adopting extra adaptive optics hardware components. A virtual phase filter constructed through combination of Zernike polynomials is adopted to eliminate the wavefront aberration, and their coefficients are stochastically estimated in parallel through the optimization of the image metrics. The feasibility of the proposed method is validated by a simulated resolution target image, in which the introduced ...

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    4. Single-shot two-dimensional spectroscopic magnetomotive optical coherence elastography with graphics processing unit acceleration

      Single-shot two-dimensional spectroscopic magnetomotive optical coherence elastography with graphics processing unit acceleration

      Biomechanical contrast within tissues can be assessed based on the resonant frequency probed by spectroscopic magnetomotive optical coherence elastography (MM-OCE). However, to date, in vivo MM-OCE imaging has not been achieved, mainly due to the constraints on imaging speed. Previously, spatially-resolved spectroscopic contrast was achieved in a “multiple-excitation, multiple-acquisition” manner, where seconds of coil cooling time set between consecutive imaging frames lead to total acquisition times of tens of minutes. Here, we demonstrate an improved data acquisition speed by providing a single chirped force excitation prior to magnetomotion imaging with a BM-scan configuration. In addition, elastogram reconstruction was accelerated by ...

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    5. Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography (OCT) is an optical imaging modality that has been investigated for real‐time surgical margin evaluation in human breast cancer patients. Previous veterinary OCT studies have been limited to surgical margin imaging for soft tissue sarcoma (STS) tumors. To the authors knowledge, OCT has never been used to characterize or evaluate other types of neoplasia in dogs. The goal of this study was to characterize the OCT imaging appearance of apocrine gland anal sac adenocarcinoma (AGASACA) in excised ex vivo specimens from five client‐owned dogs. All excised tissue surgical margins were imaged using a clinical spectral ...

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    6. Evaluating optical coherence tomography for surgical margin assessment of canine mammary tumors

      Evaluating optical coherence tomography for surgical margin assessment of canine mammary tumors

      Optical coherence tomography (OCT) uses near‐infrared light waves to generate real‐time, high‐resolution images on the microscopic scale similar to low power histopathology. Previous studies have demonstrated the use of OCT for real‐time surgical margin assessment for human breast cancer. The use of OCT for canine mammary tumors (CMT) could allow intra‐operative visualization of residual tumor at surgical margins. The purpose of this study was to assess OCT imaging for the detection of incomplete tumor resection following CMT surgery. We hypothesized that OCT images would have comparable features to histopathological images of tissues at the surgical ...

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    7. Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope

      Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope

      Objective To determine the feasibility of detecting and differentiating middle ear effusions (MEEs) using an optical coherence tomography (OCT) otoscope. Study Design Cross-sectional study. Setting US tertiary care children’s hospital. Subjects and Methods Seventy pediatric patients undergoing tympanostomy tube placement were preoperatively imaged using an OCT otoscope. A blinded reader quiz was conducted using 24 readers from 4 groups of tiered medical expertise. The primary outcome assessed was reader ability to detect presence/absence of MEE. A secondary outcome assessed was reader ability to differentiate serous vs nonserous MEE. Results OCT image data sets were analyzed from 45 of ...

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    8. Assessing the Effect of Middle Ear Effusions on Wideband Acoustic Immittance Using Optical Coherence Tomography

      Assessing the Effect of Middle Ear Effusions on Wideband Acoustic Immittance Using Optical Coherence Tomography

      Objectives: Wideband acoustic immittance (WAI) noninvasively assesses middle ear function by measuring the sound conduction over a range of audible frequencies. Although several studies have shown the potential of WAI for detecting the presence of middle ear effusions (MEEs), determining the effects of MEE type and amount on WAI in vivo has been challenging due to the anatomical location of middle ear cavity. The purpose of this study is to correlate WAI measurements with physical characteristics of the middle ear and MEEs determined by optical coherence tomography (OCT), a noninvasive optical imaging technique. Design: Sixteen pediatric subjects (average age of ...

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    9. Comparison between optical coherence tomographic and histopathologic appearances of artifacts caused by common surgical conditions and instrumentation

      Comparison between optical coherence tomographic and histopathologic appearances of artifacts caused by common surgical conditions and instrumentation

      Objective To document the appearance of artifacts created by commonly encountered surgical conditions and instrumentation on optical coherence tomography (OCT) and to compare these findings with histopathology. Study design Ex vivo study. Animals Five canine cadavers. Methods Skin, subcutaneous fat, skeletal muscle, and fascia samples were obtained from fresh canine cadavers. Blood pooling, hemostatic crushing, scalpel blade cut, monopolar electrosurgery, bipolar vessel sealing device, and ultrasonic energy surgical artifacts were induced on each tissue type. Each specimen was imaged with OCT and subsequently histologically processed. Results Most surgical instrumentation used for tumor excision created a high‐scattering region with local ...

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    10. Method and apparatus for OCT-based viscometry

      Method and apparatus for OCT-based viscometry

      Methods and apparatus for ascertaining a relative viscosity characterizing a fluid sample. The fluid sample is illuminated through a scattering membrane adjacent to the fluid with broadband radiation. Scattering from particles within the fluid sample characterized by a distribution of characteristic dimensions spanning at least two orders of magnitude is detected, generating a detector signal as a function of depth relative to a specified surface of the scattering membrane at a plurality of temporal delays. A cross-correlation function of at least one of amplitude, phase and intensity of a scattered optical field is derived for a plurality of depths relative ...

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    11. Automated classification platform for the identification of otitis media using optical coherence tomography

      Automated classification platform for the identification of otitis media using optical coherence tomography

      The diagnosis and treatment of otitis media (OM), a common childhood infection, is a significant burden on the healthcare system. Diagnosis relies on observer experience via otoscopy, although for non-specialists or inexperienced users, accurate diagnosis can be difficult. In past studies, optical coherence tomography (OCT) has been used to quantitatively characterize disease states of OM, although with the involvement of experts to interpret and correlate image-based indicators of infection with clinical information. In this paper, a flexible and comprehensive framework is presented that automatically extracts features from OCT images, classifies data, and presents clinically relevant results in a user-friendly platform ...

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    12. Local wavefront mapping in tissue using computational adaptive optics OCT

      Local wavefront mapping in tissue using computational adaptive optics OCT

      The identification and correction of wavefront aberrations is often necessary to achieve high-resolution optical images of biological tissues, as imperfections in the optical system and the tissue itself distort the imaging beam. Measuring the localized wavefront aberration provides information on where the beam is distorted and how severely. We have recently developed a method to estimate the single-pass wavefront aberrations from complex optical coherence tomography (OCT) data. Using this method, localized wavefront measurement and correction using computational OCT was performed in ex vivo tissues. The computationally measured wavefront varied throughout the imaged OCT volumes and, therefore, a local wavefront correction ...

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    13. Interstitial magnetic thermotherapy dosimetry based on shear wave magnetomotive optical coherence elastography

      Interstitial magnetic thermotherapy dosimetry based on shear wave magnetomotive optical coherence elastography

      While magnetic thermoseeds are often utilized in interstitial magnetic thermotherapy (iMT) to enable localized tumor ablation, we propose to extend their use as the perturbative source in magnetomotive optical coherence elastography (MM-OCE) so that the heat-induced elasticity alterations can be ‘theranostically’ probed. MM-OCE measurements were found to agree with indentation results. Tissue stiffening was visualized on iMT-treated porcine liver and canine soft tissue sarcoma specimens, where histology confirmed thermal damages. Additionally, the elasticity was found to increase exponentially and linearly with the conventional thermal dosage metrics and the deposited thermal energy, respectively. Collectively, a physiologically-meaningful, MM-OCE-based iMT dosimetry is feasible.

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    14. Economical and compact briefcase spectral-domain optical coherence tomography system for primary care and point-of-care applications

      Economical and compact briefcase spectral-domain optical coherence tomography system for primary care and point-of-care applications

      Development of low-cost and portable optical coherence tomography (OCT) systems is of global interest in the OCT research community. Such systems enable utility broadly throughout a clinical facility, or in remote areas that often lack clinical infrastructure. We report the development and validation of a low-cost, portable briefcase spectral-domain optical coherence tomography (SD-OCT) system for point-of-care diagnostics in primary care centers and/or in remote settings. The self-contained briefcase OCT contains all associated optical hardware, including light source, spectrometer, hand-held probe, and a laptop. Additionally, this system utilizes unique real-time mosaicking of surface video images that are synchronized with rapid ...

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    15. Intraoperative imaging of surgical margins of canine soft tissue sarcoma using optical coherence tomography

      Intraoperative imaging of surgical margins of canine soft tissue sarcoma using optical coherence tomography

      Optical coherence tomography (OCT) is a rapid non‐invasive imaging technique that has shown high sensitivity for intraoperative surgical margin assessment in human breast cancer clinical trials. This promising technology has not been evaluated in veterinary medicine. The objective of this study was to correlate normal and abnormal histological features with OCT images for surgical margins from excised canine soft tissue sarcoma (STS) and to establish image evaluation criteria for identifying positive surgical margins. Fourteen client‐owned dogs underwent surgical resection of a STS and OCT imaging of 2‐4 areas of interest on the resected specimen were performed. Following ...

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    16. Image Data Analyst, GlaxoSmithKline Center for Optical Molecular Imaging, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign

      Image Data Analyst, GlaxoSmithKline Center for Optical Molecular Imaging, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign

      Image Data Analyst GlaxoSmithKline Center for Optical Molecular Imaging Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign The GlaxoSmithKline Center for Optical Molecular Imaging at the Beckman Institute for Advanced Science and Technology seeks a bright, energetic, and motivated candidate to fill a vacancy for a full-time Image Data Analyst. The purpose of this position is to lead the analysis of image data from translational optical biomedical imaging systems. The successful candidate will need a solid and broad understanding of image analysis software as well as software development including high-level user interface requirements in a Windows ...

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    17. Imaging Research Scientist, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign

      Imaging Research Scientist, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign

      The Biophotonics Imaging Laboratory and the Center for Optical Molecular Imaging at the Beckman Institute for Advanced Science and Technology seek to fill a position for a full-time Imaging Research Scientist. The purpose of this position is to develop and operate optical imaging technologies and systems, and perform and/or manage translational imaging studies involving cell lines, pre-clinical animal models, human subjects, and/or human tissue specimens. This position will work closely with research personnel and physicians, and will also interface with industry partners and collaborators at GlaxoSmithKline. Duties and Responsibilities: Innovate and develop novel optical imaging systems, including both ...

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    18. Intraoperative breast cancer margin detection via polarization-sensitive optical coherence tomography

      Intraoperative breast cancer margin detection via polarization-sensitive optical coherence tomography

      Current standard-of-care for breast conserving surgery (BCS) procedures relies on post-operative histopathology to provide a microscopic view and assessment of surgical margins. To avoid high reoperation rates there has been a great interest in developing new imaging solutions to visualize tissue intraoperatively, and provide real-time feedback on the margin status. Optical coherence tomography (OCT) is a high-resolution label-free, imaging technology that is the optical analogue to ultrasound imaging, except images are based on backscattered near-infrared light. Fundamentally, the contrast mechanism of OCT relies on the light scattering properties associated with different tissue structures. Unlike normal tissue with well-organized tissue structure ...

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    19. Magnetomotive Displacement of the Tympanic Membrane using Magnetic Nanoparticles: Toward Enhancement of Sound Perception

      Magnetomotive Displacement of the Tympanic Membrane using Magnetic Nanoparticles: Toward Enhancement of Sound Perception

      Objective: A novel hearing-aid scheme using magnetomotive nanoparticles (MNPs) as transducers in the tympanic membrane (TM) is proposed, aiming to noninvasively and directly induce a modulated vibration on the TM. Methods: In this feasibility study, iron-oxide (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles were applied on ex vivo rat TM tissues and allowed to diffuse over ~2 hr. Subsequently, magnetic force was exerted on the MNP-laden TM via a programmable electromagnetic solenoid to induce the magnetomotion. Optical coherence tomography (OCT), along with its phase-sensitive measurement capabilities, was utilized to visualize and quantify the nanometer-scale vibrations generated on the ...

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    20. Wavefront measurement using computational adaptive optics

      Wavefront measurement using computational adaptive optics

      In many optical imaging applications, it is necessary to correct for aberrations to obtain high quality images. Optical coherence tomography (OCT) provides access to the amplitude and phase of the backscattered optical field for three-dimensional (3D) imaging samples. Computational adaptive optics (CAO) modifies the phase of the OCT data in the spatial frequency domain to correct optical aberrations without using a deformable mirror, as is commonly done in hardware-based adaptive optics (AO). This provides improvement of image quality throughout the 3D volume, enabling imaging across greater depth ranges and in highly aberrated samples. However, the CAO aberration correction has a ...

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    21. Label-free optical imaging technologies for rapid translation and use during intraoperative surgical and tumor margin assessment

      Label-free optical imaging technologies for rapid translation and use during intraoperative surgical and tumor margin assessment

      The biannual International Conference on Biophotonics was recently held on April 30 to May 1, 2017, in Fremantle, Western Australia. This continuing conference series brought together key opinion leaders in biophotonics to present their latest results and, importantly, to participate in discussions on the future of the field and what opportunities exist when we collectively work together for using biophotonics for biological discovery and medical applications. One session in this conference, entitled “Tumor Margin Identification: Critiquing Technologies,” challenged invited speakers and attendees to review and critique representative label-free optical imaging technologies and their application for intraoperative assessment and guidance in ...

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    22. Review of optical coherence tomography in oncology

      Review of optical coherence tomography in oncology

      The application of optical coherence tomography (OCT) in the field of oncology has been prospering over the past decade. OCT imaging has been used to image a broad spectrum of malignancies, including those arising in the breast, brain, bladder, the gastrointestinal, respiratory, and reproductive tracts, the skin, and oral cavity, among others. OCT imaging has initially been applied for guiding biopsies, for intraoperatively evaluating tumor margins and lymph nodes, and for the early detection of small lesions that would often not be visible on gross examination, tasks that align well with the clinical emphasis on early detection and intervention. Recently ...

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    23. Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention

      Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention

      In an institutional review board-approved study, 25 pediatric subjects diagnosed with chronic or recurrent otitis media were observed over a period of six months with optical coherence tomography (OCT). Subjects were followed throughout their treatment at the initial patient evaluation and preoperative consultation, surgery (intraoperative imaging), and postoperative follow-up, followed by an additional six months of records-based observation. At each time point, the tympanic membrane (at the light reflex region) and directly adjacent middle-ear cavity were observed in vivo with a handheld OCT probe and portable system. Imaging results were compared with clinical outcomes to correlate the clearance of symptoms ...

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    24. Clinical translation of handheld optical coherence tomography: practical considerations and recent advancements

      Clinical translation of handheld optical coherence tomography: practical considerations and recent advancements

      Since the inception of optical coherence tomography (OCT), advancements in imaging system design and handheld probes have allowed for numerous advancements in disease diagnostics and characterization of the structural and optical properties of tissue. OCT system developers continue to reduce form factor and cost, while improving imaging performance (speed, resolution, etc.) and flexibility for applicability in a broad range of fields, and nearly every clinical specialty. An extensive array of components to construct customized systems has also become available, with a range of commercial entities that produce high-quality products, from single components to full systems, for clinical and research use ...

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