1. Articles from Frederick H. Silver

    1-19 of 19
    1. “Fingerprinting” Benign and Cancerous Skin Lesions Using Vibrational Optical Coherence Tomography: Differentiation among Cancerous Lesion Types Based on the Presence of New Cells, Blood Vessels, and Fibrosis

      “Fingerprinting” Benign and Cancerous Skin Lesions Using Vibrational Optical Coherence Tomography: Differentiation among Cancerous Lesion Types Based on the Presence of New Cells, Blood Vessels, and Fibrosis

      In this study, we use vibrational optical coherence tomography (VOCT) to examine the morphology and stiffness of benign and cancerous lesions. Lesion images and 3D plots of weighted displacement versus frequency and depth were used to compare the cellular, dermal collagen, new blood vessels, and fibrotic composition of normal skin, actinic keratoses (AK), nodular and superficial basal cell carcinomas (BCCs), squamous cell carcinomas (SCCs), and melanomas. The results of this study suggest that benign and cancerous lesions differ based on the addition of new cells with increased resonant frequency and stiffness (80 Hz, 1.8 MPa), new blood vessel peaks ...

      Read Full Article
      Mentions: OptoVibronex
    2. In Vivo Determination of the Human Corneal Elastic Modulus Using Vibrational Optical Coherence Tomography

      In Vivo Determination of the Human Corneal Elastic Modulus Using Vibrational Optical Coherence Tomography

      Purpose : To determine the in vivo elastic modulus of the human cornea using vibrational optical coherence tomography (VOCT). Methods : Vibrational analysis coupled with optical coherence tomography (OCT) was used to obtain the resonant frequency (RF) and elastic modulus of corneal structural components. VOCT corneal thickness values were measured using OCT images and correlated with corneal thickness determined with Pentacam (Oculus, Wetzlar, Germany). Moduli were obtained at two locations: central cornea (CC) and inferior cornea (IC). Measurements were obtained with and without anesthetic eye drops to assess their effect on the modulus measurements. Results : VOCT thickness values correlated positively ( R 2 ...

      Read Full Article
    3. The “Virtual Biopsy” of Cancerous Lesions in 3D: Non-Invasive Differentiation between Melanoma and Other Lesions Using Vibrational Optical Coherence Tomography

      The “Virtual Biopsy” of Cancerous Lesions in 3D: Non-Invasive Differentiation between Melanoma and Other Lesions Using Vibrational Optical Coherence Tomography

      Early detection of skin cancer is of critical importance to provide five year survival rates that approach 99%. By 2050, one out of five Americans by age 70 will develop some form of skin cancer. This will result in a projected rate of 50 million skin biopsies per year given the current rate of escalation. In addition, the ability to differentiate between pigmented lesions and melanomas has proven a diagnostic challenge. While dermoscopy and visual analysis are useful in identifying many skin lesions, additional non-invasive techniques are needed to assist in the analysis of difficult to diagnose skin tumors. To ...

      Read Full Article
      Mentions: OptoVibronex
    4. Characterization of the Biomechanical Properties of Skin Using Vibrational Optical Coherence Tomography: Do Changes in the Biomechanical Properties of Skin Stroma Reflect Structural Changes in the Extracellular Matrix of Cancerous Lesions?

      Characterization of the Biomechanical Properties of Skin Using Vibrational Optical Coherence Tomography: Do Changes in the Biomechanical Properties of Skin Stroma Reflect Structural Changes in the Extracellular Matrix of Cancerous Lesions?

      Early detection of skin cancer is of critical importance since the five-year survival rate for early detected skin malignancies is 99% but drops to 27% for cancer that has spread to distant lymph nodes and other organs. Over 2.5 million benign skin biopsies (55% of the total) are performed each year in the US at an alarming cost of USD ~2.5 B. Therefore there is an unmet need for novel non-invasive diagnostic approaches to better differentiate between cancerous and non-cancerous lesions, especially in cases when there is a legitimate doubt that a biopsy may be required. The purpose ...

      Read Full Article
    5. Use of vibrational optical coherence tomography to measure viscoelastic properties of muscle and tendon: A new method to follow musculoskeletal injury and pathology In vivo

      Use of vibrational optical coherence tomography to measure viscoelastic properties of muscle and tendon: A new method to follow musculoskeletal injury and pathology In vivo

      The biomechanical properties of muscles and tendons in vivo are important parameters needed to understand musculoskeletal physiology and pathology. Values of the shear moduli reported for human musculoskeletal components using elastographic techniques range from several KPa to about 100 KPa and are much lower than the tensile moduli measured in vivo which are reported to be as high as several hundred MPa at high strains. In this paper we report the results of a pilot study to measure the mechanical properties of human muscles and tendons non-invasively and non-destructively in vivo using vibrational optical coherence tomography (VOCT). VOCT is a ...

      Read Full Article
    6. Use of Vibrational Optical Coherence Tomography to Analyze the Mechanical Properties of Composite Materials

      Use of Vibrational Optical Coherence Tomography to Analyze the Mechanical Properties of Composite Materials

      Energy storage and dissipation by composite materials are important design parameters for sensors and other devices. While polymeric materials can reversibly store energy by decreased chain randomness (entropic loss) they fail to be able to dissipate energy effectively and ultimately fail due to fatigue and molecular chain breakage. In contrast, composite tissues, such as muscle and tendon complexes, store and dissipate energy through entropic changes in collagen (energy storage) and viscous losses (energy dissipation) by muscle fibers or through fluid flow of the interfibrillar matrix. In this paper we review the molecular basis for energy storage and dissipation by natural ...

      Read Full Article
    7. Mechano-Vibrational Spectroscopy of Tissues and Materials Using Vibrational Optical Coherence Tomography: A New Non-Invasive and Non-Destructive Technique

      Mechano-Vibrational Spectroscopy of Tissues and Materials Using Vibrational Optical Coherence Tomography: A New Non-Invasive and Non-Destructive Technique

      Elastic moduli of tissues andsynthetic polymeric materials are important design properties needed to develop new implants. In this paper we report the use of vibrational optical coherence tomography (VOCT) to measure the resonant frequency and calculate the modulus of tissues and synthetic polymers non-invasively and non-destructively in vitro and in vivo . Values of tissue and polymer moduli were obtained by applying an audible sinusoidal sound wave to the surface of each specimen. The sound wave travels to the interior of the material and is reflected back to the surface from underlying layers. A spectrum of resonant frequencies and moduli are ...

      Read Full Article
    8. Mechano‐vibrational spectroscopy of skin: Are changes in collagen and vascular tissue components early signs of basal cell carcinoma formation?

      Mechano‐vibrational spectroscopy of skin: Are changes in collagen and vascular tissue components early signs of basal cell carcinoma formation?

      Background The modulus and resonant frequency of cancer cells and extracellular matrix are increased in both basal cell and squamous cell carcinomas, and in addition, the collagen stiffness is increased. The organization of the extracellular matrix surrounding cancer cells is clearly different than the extracellular matrix that is seen in normal skin. Materials and Methods We have used vibrational optical coherence tomography (VOCT) to measure the resonant frequency and stiffness of collagen, vascular, and reorganized fibrous extracellular matrix components. Measurements of vessels and fibrotic collagen content made on basal cell carcinomas (BCCs) are compared to similar measurements made on normal ...

      Read Full Article
    9. “Virtual Biopsies” of Normal Skin and Thermal and Chemical Burn Wounds

      “Virtual Biopsies” of Normal Skin and Thermal and Chemical Burn Wounds

      The search for noninvasive methods to image and measure the mechanical properties of skin has been a frequent subject of research for many years. Although suction testing, elastography, and other testing can be noninvasive, these tests fail to yield comparable results to destructive tests such as uniaxial tensile testing. Accordingly, researchers have developed a technique to combine optical coherence tomography with vibrational analysis ( vibrational optical coherence tomography ) to image and analyze the biomechanical properties of tissues noninvasively and nondestructively. The result of this analysis is a “ virtual biopsy ” of skin , along with a physical analysis of the major components of ...

      Read Full Article
    10. Comparison of Normal Skin and Thermal and Chemical Burn Wounds using Vibrational Optical Coherence Tomography

      Comparison of Normal Skin and Thermal and Chemical Burn Wounds using Vibrational Optical Coherence Tomography

      he search for methods to evaluate the extent and severity of skin lesions, such as burns and other skin disorders, has been a subject of extentive research. While suction testing, elastography and other tests can be done noninvasively on intact skin, these tests cannot be done on burns and open wounds due to the possible injury that may occur. In addition, they fail to yield comparable results obtained using destructive tests such as uniaxial tensile testing. We have developed a technique to combine optical coherence tomography (OCT) with vibrational analysis (VOCT) to non-invasively and non-destructively evaluate the properties of skin ...

      Read Full Article
      Mentions: Lumedica
    11. Biomechanical Relationship Between Cells and Collagen in Skin and Skin Lesions

      Biomechanical Relationship Between Cells and Collagen in Skin and Skin Lesions

      We have used vibrational optical coherence tomography to study the relationship between cellular and collagen mechanical behavior in skin in-vivo. Quantitative measurements of the cellular and collagen resonant frequencies and peak heights were used to calculate the moduli and relative contribution of cells and collagen to the mechanical behavior of skin. Our results suggest that the resonant frequencies measured in vascularized skin are increased by arterial blood flow and is hypothesized to be a result of upregulation of mechanotransduction. The increased cell contribution to the pixel intensity and an increased resonant frequency peak height, suggests that arterial flow influences the ...

      Read Full Article
    12. Use of Vibrational Optical Coherence Tomography to Image and Characterize a Squamous Cell Carcinoma

      Use of Vibrational Optical Coherence Tomography to Image and Characterize a Squamous Cell Carcinoma

      Previous literature reports suggest that tissue stiffness is a predictor of cancer and metastatic behavior. We have used optical coherence tomography and vibrational analysis (VOCT) to characterize normal skin, scar and a verrucous carcinoma, a squamous cell carcinoma subtype, non-invasively and nondestructively. The results suggest that epidermal thickening and increased keratin production occur in verrucous carcinoma and lead to increases in surface hills and valleys as well as subsequent increases in epidermal stiffness values. Increased stiffness of the epidermis is a result of increased keratin production while the stiffness of the dermis remains similar to that of normal skin, suggesting ...

      Read Full Article
    13. Use of Vibrational Optical Coherence Tomography to Characterize Skin Lesions and a Congenital Nevus

      Use of Vibrational Optical Coherence Tomography to Characterize Skin Lesions and a Congenital Nevus

      We have used vibrational optical coherence tomography (VOCT) to image and measure the mechanical properties of normal skin and skin lesions. It is observed that in a congenital nevus and normal skin, the cellular epidermis is qualitatively not as bright as in skin lesions including basal cell carcinoma, actinic keratosis and a melanocytic nevus. Melanin and cytochrome c oxidase are reported to attenuate the reflection of near-infrared light at a wavelength of 810 nm and therefore may explain the reduced reflection of light in a congenital nevus and normal skin under conditions where cytochrome c oxidase levels would be expected ...

      Read Full Article
    14. Comparative “virtual biopsies” of normal skin and skin lesions using vibrational optical coherence tomography

      Comparative “virtual biopsies” of normal skin and skin lesions using vibrational optical coherence tomography

      Background Increased tissue stiffness (also termed modulus) has been shown to be a characteristic of potential tumor metastasis. Measured values of the stiffness of tumors and cancer cells are reported in the literature to increase compared to neighboring normal tissues. Yet the relationship between the mechanical properties of cells and the extracellular matrix has yet to be correlated with the histopathology of cancerous lesions. Materials and Methods We have developed a technique to do virtual biopsies of skin lesions by combining images made using optical coherence tomography with stiffness measurements made simultaneously using vibrational analysis. The technique is termed vibrational ...

      Read Full Article
      Mentions: OptoVibronex
    15. Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations

      Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations

      Experimental measurements made in this study on human and porcine eyes suggest that the resonant frequency for both cornea and sclera varies from 130 to 150 Hz and increases slightly with increasing intraocular pressure. The values of the moduli calculated using the experimental values of the thickness are close to 2 MPa. Similar values of the modulus for cornea and sclera suggest that there is very little stress concentration at the cornea-scleral junction and that any stress concentration that occurs probably resides at the scleral attachment laterally and posteriorly. These moduli are close to those measured in vivo on human ...

      Read Full Article
    16. Biomechanical analysis of decellularized dermis and skin: Initial in vivo observations using OCT and vibrational analysis

      Biomechanical analysis of decellularized dermis and skin: Initial in vivo observations using OCT and vibrational analysis

      Measurement of the mechanical properties of skin in vivo has been complicated by the lack of methods that can accurately measure the viscoelastic properties without assuming values of Poisson's ratio and tissue density. In this paper, we present the results of preliminary studies comparing the mechanical properties of skin and scar tissue measured using a technique involving OCT and vibrational analysis. This technique has been reported to give values of the modulus that correlate with those obtained from tensile measurements made on decellularized dermis [1, 2]. The high correlation between moduli measured using vibrational studies and uniaxial tensile tests ...

      Read Full Article
    17. Viscoelastic Behavior of Tissues and Implant Materials: Estimation of the Elastic Modulus and Viscous Contribution Using Optical Coherence Tomography and Vibrational Analysis

      Viscoelastic Behavior of Tissues and Implant Materials: Estimation of the Elastic Modulus and Viscous Contribution Using Optical Coherence Tomography and Vibrational Analysis

      Recently, we have reported use of Optical Coherence Tomography (OCT) and vibrational analysis to determine the resonant frequency of a material from which the moduli of decellularized dermis, pig skin, silicone rubber and chemically modified dermis were calculated. In this paper, we present data on viscoelastic mechanical properties of extracellular matrices and silicone rubber at frequencies above and below the resonant frequency. The results reported suggest that measurement of the modulus at the resonant frequency of a viscoelastic material provides a good estimate of the elastic modulus while measurements below and above the resonant frequency contain a larger viscous contribution ...

      Read Full Article
    18. Analysis of Mechanical Behavior of Composite Tissues Using Vibrational Optical Coherence Tomography

      Analysis of Mechanical Behavior of Composite Tissues Using Vibrational Optical Coherence Tomography

      Extracellular matrices (ECMs) found in vertebrate tissues are fiber reinforced composite materials that prevent premature mechanical failure, store, transmit, and dissipate mechanical energy generated by the musculoskeletal system. We have developed a new method using optical cohesion tomography and vibrational analysis to non-destructively and non-invasively measure the mechanical properties of composite tissues and polymeric materials. In addition, this method can be used to measure the moduli of individual components of composite materials and perform “mechanical spectroscopy” on materials. In addition, we propose that measurement of the resonant frequency of a material minimizes the viscoelastic behavior of a composite material. This ...

      Read Full Article
    1-19 of 19
  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. (3 articles) OptoVibronex
    2. (1 articles) Thomas Jefferson University
    3. (1 articles) Yale University
    4. (1 articles) Lumedica
    5. (1 articles) Mount Sinai School of Medicine
    6. (1 articles) Tokyo Medical & Dental University
  3. Popular Articles

  4. Picture Gallery

    Analysis of Mechanical Behavior of Composite Tissues Using Vibrational Optical Coherence Tomography Viscoelastic Behavior of Tissues and Implant Materials: Estimation of the Elastic Modulus and Viscous Contribution Using Optical Coherence Tomography and Vibrational Analysis Biomechanical analysis of decellularized dermis and skin: Initial in vivo observations using OCT and vibrational analysis Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations Comparative “virtual biopsies” of normal skin and skin lesions using vibrational optical coherence tomography Use of Vibrational Optical Coherence Tomography to Characterize Skin Lesions and a Congenital Nevus Use of Vibrational Optical Coherence Tomography to Image and Characterize a Squamous Cell Carcinoma Comparison of Normal Skin and Thermal and Chemical Burn Wounds using Vibrational Optical Coherence Tomography “Virtual Biopsies” of Normal Skin and Thermal and Chemical Burn Wounds The “Virtual Biopsy” of Cancerous Lesions in 3D: Non-Invasive Differentiation between Melanoma and Other Lesions Using Vibrational Optical Coherence Tomography Diagnostic accuracy of OCTA and OCT for myopic choroidal neovascularisation: a systematic review and meta-analysis Intraoperative Use of Wide-Field Optical Coherence Tomography to Evaluate Tissue Microstructure in the Oral Cavity and Oropharynx