1. Articles from Mark E. Brezinski

    1-24 of 27 1 2 »
    1. Comparing the Risk Factors of Plaque Rupture and Failed Plaque Healing in Acute Coronary Syndrome

      Comparing the Risk Factors of Plaque Rupture and Failed Plaque Healing in Acute Coronary Syndrome

      The article by Vergallo et al 1 in this issue of JAMA Cardiology supports a hypothesis that healed plaques are a marker for reduced acute coronary syndrome (ACS) risk. This commentary expands on this idea by examining a mechanistic hypothesis of their results beyond looking at healing just as a marker. Specifically, failed healing, which correlated in the study by Vergallo et al 1 with long core axial extent, predisposes plaque ruptures to progress to ACS. Acute coronary syndrome may require a double hit of both rupture and impaired healing. This is somewhat analogous to the situation in oncology, where ...

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    2. A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, and Quantum Noise

      A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, and Quantum Noise

      Optical coherence tomography has become an important imaging technology in cardiology and ophthalmology, with other applications under investigations. Major advances in optical coherence tomography (OCT) imaging are likely to occur through a quantum field approach to the technology. In this paper, which is the first part in a series on the topic, the quantum basis of OCT first order correlations is expressed in terms of full field quantization. Specifically first order correlations are treated as the linear sum of single photon interferences along indistinguishable paths. Photons and the electromagnetic (EM) field are described in terms of quantum harmonic oscillators. While ...

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    3. Current OCT Approaches Do Not Reliably Identify TCFAs

      Current OCT Approaches Do Not Reliably Identify TCFAs

      It is now clearly established that Thin-Capped Fibroatheromas (TCFAs) lead to most Acute Coronary Syndromes (ACSs). The ability to selectively intervene on TCFAs predisposed to rupture and ACSs would dramatically alter the practice of cardiology. While the ability of OCT to identify thin walled plaques at micron scale resolutions has represented a major advance, it is a misconception that it can reliably identify TCFAs. One major reason is that the ‘diffuse border’ criteria currently used to determine ‘lipid plaque’ is almost undoubtedly from high scattering in the intima and not because of core composition (necrotic core). A second reason is ...

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    4. Longitudinal necrotic shafts near TCFAs—A potential novel mechanism for plaque rupture to trigger ACS?

      Longitudinal necrotic shafts near TCFAs—A potential novel mechanism for plaque rupture to trigger ACS?

      It has been questioned for over 15 years why only less than 20% of TCFAs trigger ACS. We illustrate TCFA rupture into adjacent longitudinal necrotic shafts of massive amounts of thrombogenic material into the blood, leading to catastrophic clot formation. This is the potential mechanism for TCFAs triggering ACS. One case presented also illustrates the dangers of stent edges rupturing TCFAs.

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    5. A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, And Quantum Noise

      A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, And Quantum Noise

      Optical coherence tomography has become an important imaging technology in cardiology and ophthalmology, with other applications under investigations. Major advances in optical coherence tomography (OCT) imaging are likely to occur through a quantum field approach to the technology. In this paper, which is the first part in a series on the topic, the quantum basis of OCT first order correlations is expressed in terms of full field quantization. Specifically first order correlations are treated as the linear sum of single photon interferences along indistinguishable paths. Photons and the electromagnetic (EM) field are described in terms of quantum harmonic oscillators. While ...

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    6. Fossilized Teeth as a New Robust and Reproducible Standard for Polarization-Sensitive Optical Coherence Tomography

      Fossilized Teeth as a New Robust and Reproducible Standard for Polarization-Sensitive Optical Coherence Tomography

      A clinical need exists for a cheap and efficient standard for polarization sensitive optical coherence tomography (PS-OCT). We utilize prehistoric fossilized teeth from the Megalodon shark and European horse as an unconventional, yet robust standard. Given their easy accessibility and the microstructural consistency conferred by the process of fossilization, they provide a means of calibration to reduce error from sources such as catheter bending and temperature changes. We tested the maximum difference in birefringence values in each tooth and found the fossilized teeth to be fast and repeatable. The results were compared to measurements from bovine meniscus, tendon, and destroyed ...

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    7. Optical Coherence Tomography Principles and Applications Second Edition (Book)

      Optical Coherence Tomography Principles and Applications Second Edition (Book)

      Optical coherence tomography is a medical high-resolution imaging technology which offers several distinct advantages over current medical imaging technologies. With a resolution 25x greater than current technologies, its ability to be engineered very small due to its fiber-based design these devices, and it is high speed with frame rates close to video rates, this technology is attracting a great many researchers. This second edition brings together information needed by the various, and sometimes disparate, groups using and studying this technology. It is completely updated throughout with the most recent research and applications. This is not a book on how to ...

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    8. The Application of Optical Coherence Tomography in Musculoskeletal Disease

      The Application of Optical Coherence Tomography in Musculoskeletal Disease

      Many musculoskeletal disorders (MDs) are associated with irreversible bone and cartilage damage; this is particularly true for osteoarthritis (OA). Therefore, a clinical need exists for modalities which can detect OA and other MDs at early stages. Optical coherence tomography (OCT) is an infrared-based imaging, currently FDA approved in cardiology and ophthalmology, which has a resolution greater than 10 microns and acquisition rate of 120 frames/second. It has shown feasibility for imaging early OA, identifying changes prior to cartilage thinning both in vitro and in vivo in patients and in OA animal models. In addition, OCT has shown an ability ...

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    9. The Advantages of Not Entangling Macroscopic Diamonds at Room Temperature

      The Advantages of Not Entangling Macroscopic Diamonds at Room Temperature

      The recent paper entitled by K. C. Lee et al. (2011) establishes nonlocal macroscopic quantum correlations, which they term “entanglement”, under ambient conditions. Photon(s)-phonon entanglements are established within each interferometer arm. However, our analysis demonstrates, the phonon fields between arms become correlated as a result of single-photon wavepacket path indistinguishability, not true nonlocal entanglement. We also note that a coherence expansion (as opposed to decoherence) resulted from local entanglement which was not recognized. It occurred from nearly identical Raman scattering in each arm (importantly not meeting the Born and Markovian approximations). The ability to establish nonlocal macroscopic quantum ...

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    10. Single-Detector Polarization-Sensitive Optical Coherence Tomography for Assessment of Rotator Cuff Tendon Integrity

      Single-Detector Polarization-Sensitive Optical Coherence Tomography for Assessment of Rotator Cuff Tendon Integrity

      This preliminary study assessed trimmed supraspinatus tendons from rotator cuff repairs (RCRs) to compare the samples’ surgically cut ends and torn ends with histopathology and polarization-sensitive optical coherence tomography (PS-OCT) imaging. PS-OCT can be used to assess collagen content and organization in birefringent tissue and shows promise in RCR. The data were compared to determine correlations between luminosity measured from histopathology and PS-OCT. Bivariate plots and a simple regression were performed to assess the linearity of the 2 groups, with a predictive value of less than .05 showing significant correlation. Approximately 50% of the visually inspected supraspinatus tendons acceptable for ...

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    11. New Technological Approach To Study Rotator Cuff Pathology

      New Technological Approach To Study Rotator Cuff Pathology

      Rotator cuff repair (RCR) is a crucial surgical procedure, but has unacceptable mechanical failure rates between 25–60%. Examining supplemental synergistic interventions, such as biological augmentations (ex: growth factors) to improve fibrocartilage formation rather than scar tissue formation, would make tears more amenable to surgical repair. Due to the large number of agents and application methods (and times), improved techniques are needed for assessing RCR in animals. In particular, high-resolution real-time imaging is needed to guide tissue engineering in animal models. Optical coherence tomography (OCT) is well suited for this role, with resolutions 25 × greater than any clinical imaging modality ...

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    12. Towards Improved Collagen Assessment: Polarization-Sensitive Optical Coherence Tomography with Tailored Reference Arm Polarization

      Towards Improved Collagen Assessment: Polarization-Sensitive Optical Coherence Tomography with Tailored Reference Arm Polarization

      Single channel PS-OCT has advantages for assessing birefringent tissue components in various clinical scenarios, with implications for assessing pathology, ranging from osteoarthritis to myocardial infarction. While the technique has been successfully used both in vitro and in vivo, there have been limited attempts to optimize single channel PS-OCT with respect to performance, particularly paddle rotation. In this study, we developed and tested a new approach for the real-time assessment of birefringence through tailoring of reference arm polarization. Different polarization rotation patterns, as depicted on a Poincare sphere, were assessed with polarization filters and retarders. When further tested in tissue, PS-OCT ...

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    13. Current Capabilities and Challenges for Optical Coherence Tomography as a High-Impact Cardiovascular Imaging Modality

      Current Capabilities and Challenges for Optical Coherence Tomography as a High-Impact Cardiovascular Imaging Modality
      Impact, the ability to have a long-lasting significant influence in the field, has become the focus not only of the National Institutes of Health and the National Science Foundation but also of science in general. An article in this issue, "Optical Coherent Tomographic Analysis of In-Stent Neoatherosclerosis After Drug-Eluting Stent Implantation," deals with 2 high-impact areas of cardiology: extending the diagnostic capabilities of cardiovascular optical coherence tomography (OCT) and the cause of late drug-eluting stent failure.1 With respect to the latter, the article looks at atherosclerotic progression after drug-eluting stent placement and late development of different plaque morphologies, predominantly ...
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    14. True logarithmic amplification of frequency clock in SS-OCT for calibration

      True logarithmic amplification of frequency clock in SS-OCT for calibration
      With swept source optical coherence tomography (SS-OCT), imprecise signal calibration prevents optimal imaging of biological tissues such as coronary artery. This work demonstrates an approach using a true logarithmic amplifier to precondition the clock signal, with the effort to minimize the noises and phase errors for optimal calibration. This method was validated and tested with a high-speed SS-OCT. The experimental results manifest its superior ability on optimization of the calibration and improvement of the imaging performance. Particularly, this hardware-based approach is suitable for real-time calibration in a high-speed system where computation time is constrained.
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    15. In Vivo Micron-Scale Arthroscopic Imaging of Human Knee Osteoarthritis With Optical Coherence Tomography: Comparison With Magnetic Resonance Imaging and Arthroscopy

      In Vivo Micron-Scale Arthroscopic Imaging of Human Knee Osteoarthritis With Optical Coherence Tomography: Comparison With Magnetic Resonance Imaging and Arthroscopy
      Current treatments for osteoarthritis are pain relief and total joint arthroplasty. There is a clinical need for early osteoarthritis diagnostic methods for potential preventive interventions. The resolution achieved with radiography, magnetic resonance imaging (MRI), and arthroscopy is too limited for the assessment of early disease. The high resolution, small fiber-optic probes, and real-time imaging of optical coherence tomography (OCT) makes this method ideal for assessing articular cartilage. In this article, we describe in vivo human arthroscopic OCT with qualitative baseline comparisons made with MRI and arthroscopy. Two-year MRI follow-ups are under way to quantitatively compare OCT with MRI and to ...
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    16. Improvement in dynamic range limitation of swept source optical coherence tomography by true logarithmic amplification

      Improvement in dynamic range limitation of swept source optical coherence tomography by true logarithmic amplification
      We previously demonstrated, with both theoretical and experimental studies, the dynamic range limitation with spectral domain optical coherence tomography (OCT) relative to time domain OCT. A significant portion of this limitation was due to the difference of analog/digital conversion. In this paper, a new method of true logarithmic amplification is discussed theoretically and tested experimentally to increase the dynamic range of a swept source OCT. With the current experimental setup, an increase of the dynamic range by about 6 dB was obtained.
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    17. Real-time and high-performance calibration method for high-speed swept-source optical coherence tomography

      Real-time and high-performance calibration method for high-speed swept-source optical coherence tomography
      For high-speed swept-source optical coherence tomography (SS-OCT), the real-time calibration process to convert the OCT signal to wave number space is highly essential. A novel calibration process/algorithm using a genetic algorithm and precise interpolation is developed. This algorithm is embedded and validated in a SS-OCT system with 16-kHz A-scan rate. The performance of the new algorithm is evaluated by measuring point spread functions at two distinct locations in the entire imaging range. The data is compared to the same system but embedded with a regular calibration algorithm, which demonstrates about 20% improvement in the axial resolution. The steady improvement ...
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    18. Nonlocal quantum macroscopic superposition in a high-thermal low-purity state

      Nonlocal quantum macroscopic superposition in a high-thermal low-purity state
      Quantum state exchange between light and matter is an important ingredient for future quantum information networks as well as other applications. Photons are the fastest and simplest carriers of information for transmission but in general, it is difficult to localize and store photons, so usually one prefers choosing matter as quantum memory elements. Macroscopic superposition and nonlocal quantum interactions have received considerable interest for this purpose over recent years in fields ranging from quantum computers to cryptography, in addition to providing major insights into physical laws. However, these experiments are generally performed either with equipment or under conditions that are ...
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    19. Experimental confirmation of potential swept source optical coherence tomography performance limitations

      Experimental confirmation of potential swept source optical coherence tomography performance limitations
      OCT has demonstrated considerable potential for a wide range of medical applications. Initial work was done in the time domain (TD-OCT) approach, but recent interest has been generated with spectral domain (SD-OCT) approaches. While SD-OCT offers higher data acquisition rates and no movable parts, we recently pointed out th eoretical inferior aspects to its performance relative to TD-OC T. In this paper we focus on specific limitations of swept source OCT (SS-OCT) as this is the more versatile of the two SD-OCT embodiments. We present experimental evidence of reduced imaging penetration, increased low frequency noise, higher multiple scattering (which can ...
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    20. Ultrasound-enhanced optical coherence tomography: improved penetration and resolution

      Ultrasound-enhanced optical coherence tomography: improved penetration and resolution
      Chuanyong Huang, Bin Liu, Mark E. Brezinski Increasing penetration remains one of the most important issues in optical coherence tomography (OCT) research, which we achieved with a parallel ultrasound beam. In addition to qualitative improvements of tissue imaging, quantitative improvements in resolution of up to 28%±2% was noted. At ... [J. Opt. Soc. Am. A 25, 938-946 (2008)]
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    21. Optical Coherence Tomography Imaging in Developmental Biology

      Optical Coherence Tomography Imaging in Developmental Biology
      Optical coherence tomography (OCT) is an attractive imaging technique for developmental biology because it permits the imaging of tissue microstructure in situ, yielding micron-scale image resolution without the need for excision of a specimen and tissue processing. OCT enables repeated imaging studies to be performed on the same specimen in order to track developmental changes. OCT is analogous to ultrasound B mode imaging except that it uses low-coherence light rather than sound and performs cross-sectional imaging by measuring the backscattered intensity of light from structures in tissue (1). The principles of OCT imaging are shown schematically in Fig. 1. The ...
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    22. Optical Coherence Tomography: Principles and Applications (Book)

      Optical Coherence Tomography: Principles and Applications (Book)
      This book gives a broad treatment of the subject which will include 1)the optics, science, and physics needed to understand the technology 2)a description of applications with a critical look at how the technology will successfully address actual clinical need, and 3) a discussion of delivery of OCT to the patient, FDA approval and comparisons with available competing technologies. The required mathematical rigor will be present where needed but be presented in such a way that it will not prevent non-scientists and non-engineers from gaining a basic understanding of OCT and the applications as well as the issues ...
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    23. High-resolution imaging of progressive articular cartilage degeneration

      High-resolution imaging of progressive articular cartilage degeneration
      The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium-iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 µm. Progressive changes were ...
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    1-24 of 27 1 2 »
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    1. (27 articles) Mark E. Brezinski
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    Methods and apparatus for forward-directed optical scanning instruments Optical Coherence Tomography Imaging in Developmental Biology Optical Coherence Tomography: Principles and Applications (Book) Experimental confirmation of potential swept source optical coherence tomography performance limitations Real-time and high-performance calibration method for high-speed swept-source optical coherence tomography In Vivo Micron-Scale Arthroscopic Imaging of Human Knee Osteoarthritis With Optical Coherence Tomography: Comparison With Magnetic Resonance Imaging and Arthroscopy Single-Detector Polarization-Sensitive Optical Coherence Tomography for Assessment of Rotator Cuff Tendon Integrity The Advantages of Not Entangling Macroscopic Diamonds at Room Temperature Fossilized Teeth as a New Robust and Reproducible Standard for Polarization-Sensitive Optical Coherence Tomography High-resolution polarization-sensitive optical coherence tomography for zebrafish muscle imaging Very Late Stent Thrombosis 89 Months after Implantation of Durable Polymer Everolimus-Eluting Stent due to Late Acquired Stent Malapposition and Uncovered Struts Observed by Optical Coherence Tomography, Near-Infrared Spectroscopy and Coronary Angioscopy Optical Coherence Tomography Angiography Analysis of Retinal and Choroidal Vascular Networks during Acute, Relapsing, and Quiescent Stages of Macular Toxoplasma Retinochoroiditis