1. Articles from chetan a. patil

    1-13 of 13
    1. Photothermal optical lock-in optical coherence tomography for in vivo imaging

      Photothermal optical lock-in optical coherence tomography for in vivo imaging

      Photothermal OCT (PTOCT) provides high sensitivity to molecular targets in tissue, and occupies a spatial imaging regime that is attractive for small animal imaging. However, current implementations of PTOCT require extensive temporal sampling, resulting in slow frame rates and a large data burden that limit its in vivo utility. To address these limitations, we have implemented optical lock-in techniques for photothermal optical lock-in OCT (poli-OCT), and demonstrated the in vivo imaging capabilities of this approach. The poli-OCT signal was assessed in tissue-mimicking phantoms containing indocyanine green (ICG), an FDA approved small molecule that has not been previously imaged in vivo ...

      Read Full Article
    2. Quantifying the vascular response to ischemia with speckle variance optical coherence tomography

      Quantifying the vascular response to ischemia with speckle variance optical coherence tomography

      Longitudinal monitoring techniques for preclinical models of vascular remodeling are critical to the development of new therapies for pathological conditions such as ischemia and cancer. In models of skeletal muscle ischemia in particular, there is a lack of quantitative, non-invasive and long term assessment of vessel morphology. Here, we have applied speckle variance optical coherence tomography (OCT) methods to quantitatively assess vascular remodeling and growth in a mouse model of peripheral arterial disease. This approach was validated on two different mouse strains known to have disparate rates and abilities of recovering following induction of hind limb ischemia. These results establish ...

      Read Full Article
    3. Longitudinal study of arteriogenesis with swept source optical coherence tomography and hyperspectral imaging

      Longitudinal study of arteriogenesis with swept source optical coherence tomography and hyperspectral imaging

      Peripheral arterial disease (PAD) is an atherosclerotic disease of the extremities that leads to high rates of myocardial infarction and stroke, increased mortality, and reduced quality of life. PAD is especially prevalent in diabetic patients, and is commonly modeled by hind limb ischemia in mice to study collateral vessel development and test novel therapies. Current techniques used to assess recovery cannot obtain quantitative, physiological data non-invasively. Here, we have applied hyperspectral imaging and swept source optical coherence tomography (OCT) to study longitudinal changes in blood oxygenation and vascular morphology, respectively, intravitally in the diabetic mouse hind limb ischemia model. Additionally ...

      Read Full Article
    4. Common detector for combined raman spectroscopy-optical coherence tomography

      Common detector for combined raman spectroscopy-optical coherence tomography

      An apparatus includes first and second light sources for respectively generating broadband and monochromatic lights, a beamsplitter optically coupled to the first light source for splitting the broadband light into a reference light and a sample light, a reference arm optically coupled to the beamsplitter for receiving the reference light and returning the received reference light into the beamsplitter, a sample arm optically coupled to the beamsplitter and the second light source for combining the sample and monochromatic lights, delivering the combined light to the target of interest, collecting a backscattering light and a Raman scattering light generated from interaction ...

      Read Full Article
    5. Feature Of The Week 10/06/13: Vanderbilt University Investigates Gold Nanorod Contrast Agents for Photothermal OCT

      Feature Of The Week 10/06/13: Vanderbilt University Investigates Gold Nanorod Contrast Agents for Photothermal OCT

      Photothermal OCT (PTOCT) is a functional extension of OCT that images oscillations in optical path length due to heat release from an absorber. These oscillations are induced by an amplitude-modulated photothermal laser that is incident on the sample. After photon absorption, heat is released into the microenvironment, which alters the local geometric path length and index of refraction. Phase-sensitive PTOCT is then used to map these index of refraction oscillations. We demonstrate that PTOCT is especially sensitive to near infrared absorbing gold nanorods, a promising contrast agent and drug carrier. The PTOCT signal is also characterized with respect to imaging ...

      Read Full Article
    6. Cross-Sectional Tracking of Particle Motion in Evaporating Drops: Flow Fields and Interfacial Accumulation

      Cross-Sectional Tracking of Particle Motion in Evaporating Drops: Flow Fields and Interfacial Accumulation

      The lack of an effective technique for three-dimensional flow visualization has limited the experimental exploration of the “coffee ring effect” to the two dimensional, top-down viewpoint. In this report, high-speed, cross-sectional imaging of the flow fields was obtained by using optical coherence tomography to track particle motion in an evaporating colloidal water drop. This approach enables z-dimensional mapping of primary and secondary flow fields and changes in these fields over time. These sectional images show that 1μm diameter polystyrene particles have a highly non-uniform vertical distribution with particles accumulating at both the air-water interface and water-glass interface during drop ...

      Read Full Article
    7. In vivo imaging of gold nanorod contrast agents using photothermal optical coherence tomography

      In vivo imaging of gold nanorod contrast agents using photothermal optical coherence tomography

      Photothermal optical coherence tomography (PT-OCT) has the potential to increase the molecular specificity of OCT for in vivo pre-clinical studies of cancer, in order to better understand drug uptake and treatment response. However, the use of PT-OCT to image contrast agents in vivo has yet to be demonstrated. Here, we characterize PT-OCT imaging of gold nanorod (GNR) contrast agents, and we further apply these techniques for in vivo imaging. The PT-OCT signal was characterized and compared to a numerical model of the bio-heat equation with respect to varying photothermal chop frequency, photothermal laser power, OCT image reflectivity, and concentration of ...

      Read Full Article
    8. A clinical instrument for combined raman spectroscopy-optical coherence tomography of skin cancers

      A clinical instrument for combined raman spectroscopy-optical coherence tomography of skin cancers

      Background and Objective The current standard for diagnosis of skin cancers is visual inspection followed by biopsy and histopathology. This process can be invasive, subjective, time consuming, and costly. Optical techniques, including Optical Coherence Tomography (OCT) and Raman Spectroscopy (RS), have been developed to perform non-invasive characterization of skin lesions based on either morphological or biochemical features of disease. The objective of this work is to report a clinical instrument capable of both morphological and biochemical characterization of skin cancers with RS-OCT. Materials and Methods The portable instrument utilizes independent 785 nm RS and 1,310 nm OCT system backbones ...

      Read Full Article
    9. Integrated system for combined Raman spectroscopy–spectral domain optical coherence tomography

      Integrated system for combined Raman spectroscopy–spectral domain optical coherence tomography
      Raman spectroscopy (RS) and optical coherence tomography (OCT) are powerful tools for optical analysis of tissues with mutually complementary strengths and limitations. OCT excels at visualizing tissue microstructure but lacks molecular specificity, while RS can relay tissue biochemical composition but typically cannot relate microstructure. Previous implementations of combined RS-OCT have utilized a common sample arm while maintaining independent RS and OCT detection arms. We present the design and application of an integrated RS-OCT instrument with a common detection arm for both RS and OCT. The detector is a spectrograph capable of sequential detection of the 855-nm OCT signal and the ...
      Read Full Article
    10. Structural and biochemical characterization of the rat retina with combined Raman spectroscopy-optical coherence tomography (RS-SDOCT)

      Structural and biochemical characterization of the rat retina with combined Raman spectroscopy-optical coherence tomography (RS-SDOCT)

      Raman spectroscopy (RS) and Optical Coherence Tomography (OCT) are powerful tools for optical analysis of tissues with complimentary strengths. OCT excels and visualizing tissue microstructure while RS can relay tissue biochemical composition. Both instruments have significant potential to serve as valuable tools in non-invasive characterization of the rodent models of retinal disease. In this abstract we present the design and application of a common detector combined RS-OCT instrument for evaluating the morphological and biochemical differences in a rat model for oxygen induced retinopathy. Rat pups that have undergone a variable oxygen treatment are compared to rats raised in room air ...

      Read Full Article
    11. A clinical probe for combined Raman spectroscopy/optical coherence tomography (RS-OCT) of the skin cancers

      A clinical probe for combined Raman spectroscopy/optical coherence tomography (RS-OCT) of the skin cancers

      Skin cancer is the most commonly occurring cancer, with incidence rates rising annually. Realizing favorable outcomes requires early diagnosis, for which the current standard is biopsy followed by histopathology. This process can be invasive, subjective, time consuming, and costly. Optical techniques, including Optical Coherence Tomography (OCT) and Raman Spectroscopy (RS), have been developed to perform non-invasive characterization of skin lesions, however neither is without limitation. Here, we demonstrate a clinical instrument for morphological and biochemical characterization of skin cancers with combined RS-OCT. The portable instrument utilizes independent RS and OCT system backbones, and is integrated in a common clinical probe ...

      Read Full Article
    12. Combined raman spectroscopy-optical coherence tomography (RS-OCT) system and applications of the same

      An apparatus for evaluating a target of interest of a living subject. In one embodiment, the apparatus has a first light source for generating a broadband light, a second light source for generating a monochromatic light, a beamsplitter optically coupled to the first light source for receiving the broadband light and splitting it into a reference light and a sample light, a reference arm optically coupled to the beamsplitter for receiving the reference light and returning it into the beamsplitter, and a probe having a working end placed proximal to a target of interest of a living subject, optically coupled ...

      Read Full Article
    13. Combined Raman spectroscopy and optical coherence tomography device for tissue characterization

      Combined Raman spectroscopy and optical coherence tomography device for tissue characterization

      We report a dual-modal device capable of sequential acquisition of Raman spectroscopy (RS) and optical coherence tomography (OCT) along a common optical axis. The device enhances application of both RS and OCT by precisely guiding RS acquisition with OCT images while also compensating for the lack of molecular specificity in OCT with the biochemical specificity of RS. We characterize the system performance and demonstrate the capability to identify structurally ambiguous features within an OCT image with RS in a scattering phantom, guide acquisition of RS from a localized malignancy in ex vivo breast tissue, and perform in vivo tissue analysis ...

      Read Full Article
    1-13 of 13
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (12 articles) Vanderbilt University
    2. (11 articles) Chetan A. Patil
    3. (7 articles) Academic Medical Center at the University of Amsterdam
    4. (6 articles) Anita Mahadevan-Jansen
    5. (6 articles) Melissa C. Skala
    6. (6 articles) Ton G. van Leeuwen
    7. (3 articles) University of Twente
    8. (3 articles) Jeroen Kalkman
    9. (2 articles) Dirk J. Faber
    10. (1 articles) Nienke Bosschaart
    11. (1 articles) University of Copenhagen
    12. (1 articles) Center for Ophthalmic Optics and Lasers
    13. (1 articles) FDA
    14. (1 articles) Oregon Health & Science University
    15. (1 articles) SUNY at Stony Brook
    16. (1 articles) University College London
    17. (1 articles) David Huang
    18. (1 articles) Axel Petzold
    19. (1 articles) Perimeter Medical Imaging
    20. (1 articles) Carl Zeiss Meditec
  3. Popular Articles

  4. Picture Gallery

    Combined Raman spectroscopy and optical coherence tomography device for tissue characterization A clinical probe for combined Raman spectroscopy/optical coherence tomography (RS-OCT) of the skin cancers Structural and biochemical characterization of the rat retina with combined Raman spectroscopy-optical coherence tomography (RS-SDOCT) Integrated system for combined Raman spectroscopy–spectral domain optical coherence tomography A clinical instrument for combined raman spectroscopy-optical coherence tomography of skin cancers In vivo imaging of gold nanorod contrast agents using photothermal optical coherence tomography Cross-Sectional Tracking of Particle Motion in Evaporating Drops: Flow Fields and Interfacial Accumulation Feature Of The Week 10/06/13: Vanderbilt University Investigates Gold Nanorod Contrast Agents for Photothermal OCT Common detector for combined raman spectroscopy-optical coherence tomography EARLY SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY BIOMARKERS TO CONFIRM FELLOW EYE CHANGES IN ASYMMETRIC TYPE-2 MACULAR TELANGIECTASIA Relative Postpartum Retinal Vasoconstriction Detected With Optical Coherence Tomography Angiography 1.1 μm waveband tunable laser using emission-wavelength-controlled InAs quantum dots for swept-source optical coherence tomography applications