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.

Practical Challenges of Current Video Rate OCT Elastography: Accounting for Dynamic and Static Tissue Properties.

Optical coherence tomography (OCT) elastography (OCTE) has the potential to be an important diagnostic tool for pathologies including coronary artery disease, osteoarthritis, malignancies, and even dental caries. Many groups have performed OCTE, including our own, using a wide range of approaches. However, we will demonstrate current OCTE approaches are not scalable to real-time, in vivo imaging.

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.

Can We Advance Macroscopic Quantum Systems Outside the Framework of Complex Decoherence Theory?

Macroscopic quantum systems (MQS) are macroscopic systems driven by quantum rather than classical mechanics, a long studied area with minimal success till recently. Harnessing the benefits of quantum mechanics on a macroscopic level would revolutionize fields ranging from telecommunication to biology, the latter focused on here for reasons discussed. Contrary to misconceptions, there are no known physical laws that prevent the development of MQS.

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.

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.

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.

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.

The Advantages of Not Entangling Macroscopic Diamonds at Room Temperature.

The recent paper entitled by K. C. Lee et al.

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.

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.

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.

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.

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.

Experimental confirmation of potential swept source optical coherence tomography performance limitations.

Optical coherence tomography (OCT) has demonstrated considerable potential for a wide range of medical applications. Initial work was done in the time domain OCT (TD-OCT) approach, but recent interest has been generated with spectral domain OCT (SD-OCT) approaches. While SD-OCT offers higher data acquisition rates and no movable parts, we recently pointed out theoretical inferior aspects to its performance relative to TD-OCT.

Ultrasound-enhanced optical coherence tomography: improved penetration and resolution.

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 lower frequencies and energies the improvement occurred primarily by altering the detection of multiply scattered light (photon-phonon interaction), which was substantially greater in solids than in liquids (even though the liquid had the higher scattering coefficient).

Applications of optical coherence tomography to cardiac and musculoskeletal diseases: bench to bedside?

Selected historical aspects of the transition of optical coherence tomography (OCT) research from the bench to bedside are focused on. The primary function of the National Institutes of Health (NIH) is to improve the diagnosis and treatment of human pathologies. Therefore, research funded by the NIH should have a direct envisioned pathway for transitioning bench work to the bedside.

Theoretical and practical considerations on detection performance of time domain, Fourier domain, and swept source optical coherence tomography.

Optical coherence tomography (OCT) based on spectral interferometry has recently been examined, with authors often suggesting superior performance compared with time domain approaches. The technologies have similar resolutions and the spectral techniques may currently claim faster acquisition rates. Contrary to many current opinions, their detection parameters may be inferior.

Characterizing of tissue microstructure with single-detector polarization-sensitive optical coherence tomography.

Assessing tissue birefringence with imaging modality polarization-sensitive optical coherence tomography (PS-OCT) could improve the characterization of in vivo tissue pathology. Among the birefringent components, collagen may provide invaluable clinical information because of its alteration in disorders ranging from myocardial infarction to arthritis. But the features required of clinical imaging modality in these areas usually include the ability to assess the parameter of interest rapidly and without extensive data analysis, the characteristics that single-detector PS-OCT demonstrates.

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.

Assessment of coronary plaque collagen with polarization sensitive optical coherence tomography (PS-OCT).

Introduction: Current evidence indicates that most plaques classified as vulnerable or ruptured plaque do not lead to unstable angina or myocardial infarction. Improved methods are needed to risk stratify plaques to identify those which lead to most acute coronary syndromes. Collagen depletion in the intima overlying lipid collections appears to be a critical component of unstable plaques.

Optical coherence tomography for identifying unstable coronary plaque.

This manuscript examines intravascular imaging with optical coherence tomography (OCT). OCT is a potentially attractive intravascular imaging technology due to its high resolution, small catheters/guidewires, and ability to be combined with spectroscopic techniques. Its potential disadvantages remain its limited penetration and signal attenuation by blood.