1. Vivek J. Srinivasan

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    1. Mentioned In 69 Articles

    2. Can OCT Angiography Be Made a Quantitative Blood Measurement Tool?

      Can OCT Angiography Be Made a Quantitative Blood Measurement Tool?
      Optical Coherence Tomography Angiography (OCTA) refers to a powerful class of OCT scanning protocols and algorithms that selectively enhance the imaging of blood vessel lumens, based mainly on the motion and scattering of red blood cells (RBCs). Though OCTA is widely used in clinical and basic science applications for visualization of perfused blood vessels, OCTA is still primarily a qualitative tool. However, more quantitative hemodynamic information would better delineate disease ...
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    3. Structural and functional human retinal imaging with a fiber-based visible light OCT ophthalmoscope

      Structural and functional human retinal imaging with a fiber-based visible light OCT ophthalmoscope
      The design of a multi-functional fiber-based Optical Coherence Tomography (OCT) system for human retinal imaging with 2 micron axial resolution in tissue is described. A detailed noise characterization of two supercontinuum light sources with different pulse repetition rates is presented. The higher repetition rate and lower noise source is found to enable a sensitivity of 96 dB with 0.15 mW light power at the cornea and a 98 microsecond ...
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    4. Dynamic contrast optical coherence tomography images transit time and quantifies microvascular plasma volume and flow in the retina and choriocapillaris

      Dynamic contrast optical coherence tomography images transit time and quantifies microvascular plasma volume and flow in the retina and choriocapillaris
      Despite the prevalence of optical imaging techniques to measure hemodynamics in large retinal vessels, quantitative measurements of retinal capillary and choroidal hemodynamics have traditionally been challenging. Here, a new imaging technique called dynamic contrast optical coherence tomography (DyC-OCT) is applied in the rat eye to study microvascular blood flow in individual retinal and choroidal layersin vivo. DyC-OCT is based on imaging the transit of an intravascular tracer dynamically as it ...
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    5. Microstructural characterization of myocardial infarction with optical coherence tractography and two‐photon microscopy

      Microstructural characterization of myocardial infarction with optical coherence tractography and two‐photon microscopy
      Myocardial infarction leads to complex changes in the fiber architecture of the heart. Here, we present a novel optical approach to characterize these changes in intact hearts in three dimensions. Optical coherence tomography (OCT) was used to derive a depth‐resolved field of orientation on which tractography was performed. Tractography of healthy myocardium revealed a smooth linear transition in fiber inclination or helix angle from the epicardium to endocardium. Conversely ...
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    6. Diagnostic performance of a novel 3D neuroretinal rim parameter for glaucoma using high-density volume scans

      Diagnostic performance of a novel 3D neuroretinal rim parameter for glaucoma using high-density volume scans
      Purpose To describe optical coherence tomography angiography (OCTA) findings in multifocal choroiditis (MFC) with active lesions and to characterize the concordance between the OCTA and other traditional imaging modalities. Design Reliability and validity analysis. Methods Patients with suspected choroidal neovascularization (CNV) or acute inflammatory lesions associated with MFC were assessed in this study. All participants underwent preliminary traditional multimodal imaging including color fundus photography, fundus autofluorescence, near-infrared reflectance imaging, spectral-domain ...
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    7. Imaging and graphing of cortical vasculature using dynamically focused optical coherence microscopy angiography

      Imaging and graphing of cortical vasculature using dynamically focused optical coherence microscopy angiography
      Recently, optical coherence tomography (OCT) angiography has enabled label-free imaging of vasculature based on dynamic scattering in vessels. However, quantitative volumetric analysis of the vascular networks depicted in OCT angiography data has remained challenging. Multiple-scattering tails (artifacts specific to the imaging geometry) make automated assessment of vascular morphology problematic. We demonstrate that dynamically focused optical coherence microscopy (OCM) angiography with a high numerical aperture, chosen so the scattering length greatly ...
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    8. Noninvasive, in vivo imaging of subcortical mouse brain regions with 1.7  μm optical coherence tomography

      Noninvasive, in vivo imaging of subcortical mouse brain regions with 1.7  μm optical coherence tomography
      A spectral/Fourier domain optical coherence tomography (OCT) intravital microscope using a supercontinuum light source at 1.7 m was developed to study subcortical structures noninvasively in the living mouse brain. The benefits of 1.7 m for deep tissue brain imaging are demonstrated by quantitatively comparing OCT signal attenuation characteristics of cortical tissue across visible and near-infrared wavelengths. Imaging of hippocampal tissue architecture and white matter microvasculature are demonstrated ...
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    9. Laminar microvascular transit time distribution in the mouse somatosensory cortex revealed by Dynamic Contrast Optical Coherence Tomography

      Laminar microvascular transit time distribution in the mouse somatosensory cortex revealed by Dynamic Contrast Optical Coherence Tomography
      The transit time distribution of blood through the cerebral microvasculature both constrains oxygen delivery and governs the kinetics of neuroimaging signals such as blood-oxygen-level-dependent functional Magnetic Resonance Imaging (BOLD fMRI). However, in spite of its importance, capillary transit time distribution has been challenging to quantify comprehensively and efficiently at the microscopic level. Here, we introduce a method, called Dynamic Contrast Optical Coherence Tomography (DyC-OCT), based on dynamic cross-sectional OCT imaging ...
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    10. Cerebral metabolic rate of oxygen (CMRO2) assessed by combined Doppler and spectroscopic OCT

      Cerebral metabolic rate of oxygen (CMRO2) assessed by combined Doppler and spectroscopic OCT
      A method of measuring cortical oxygen metabolism in the mouse brain that uses independent quantitative measurements of three key parameters: cerebral blood flow (CBF), arteriovenous oxygen extraction (OE), and hemoglobin concentration ([HbT]) is presented. Measurements were performed using a single visible light spectral/Fourier domain OCT microscope, with Doppler and spectroscopic capabilities, through a thinned-skull cranial window in the mouse brain. Baseline metabolic measurements in mice are shown to be ...
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    11. University of California at Davis Receives 2015 NIH Grant for Imaging Neuronal and Capillary Dysfunction Deep in the Rodent Brain In Vivo using 1700nm Optical Coherence Microscopy and Tracer-Based Kinetics

      University of California at Davis Receives 2015 NIH Grant for Imaging Neuronal and Capillary Dysfunction Deep in the Rodent Brain In Vivo using 1700nm Optical Coherence Microscopy and Tracer-Based Kinetics
      ...in In Vivo using 1700nm Optical Coherence Microscopy and Tracer-Based Kinetics. The principal investigator is Vivek Srinivasan. The program began in 2015 and ends in 2020. Below is a summary of the proposed work. Subcor...
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    12. Mapping the 3D Connectivity of the Rat Inner Retinal Vascular Network Using OCT Angiography

      Mapping the 3D Connectivity of the Rat Inner Retinal Vascular Network Using OCT Angiography
      Purpose : The purpose of this study is to demonstrate three-dimensional (3D) graphing based on optical coherence tomography (OCT) angiography for characterization of the inner retinal vascular architecture and determination of its topologic principles. Methods : Rat eyes ( N = 3) were imaged with a 1300-nm spectral/Fourier domain OCT microscope. A topologic model of the inner retinal vascular network was obtained from OCT angiography data using a combination of automated and manually-guided ...
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    13. Micro-heterogeneity of flow in a mouse model of chronic cerebral hypoperfusion revealed by longitudinal Doppler optical coherence tomography and angiography

      Micro-heterogeneity of flow in a mouse model of chronic cerebral hypoperfusion revealed by longitudinal Doppler optical coherence tomography and angiography
      Although microvascular dysfunction accompanies cognitive decline in aging, vascular dementia, and Alzheimers disease, tools to study microvasculature longitudinally in vivo are lacking. Here, we use Doppler optical coherence tomography (OCT) and angiography for noninvasive, longitudinal imaging of mice with chronic cerebral hypoperfusion for up to 1 month. In particular, we optimized the OCT angiography method to selectively image red blood cell (RBC)-perfused capillaries, leading to a novel way of ...
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    14. 1-15 of 69 1 2 3 4 5 »
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  2. About Vivek J. Srinivasan

    Vivek J. Srinivasan

    Vivek J. Srinivasan is Assistant Professor of Biomedical Engineering at the University of California Davis. Dr. Srinivasan received his B.S. and M.S. in Electrical Engineering from Stanford University, and my PhD in EECS (bioelectrical engineering area) at MIT. His lab recently moved to the UC Davis Biomedical Engineering Department from the Martinos Center for Biomedical Imaging in the Department of Radiology at MGH. The lab has developed a range of optical tools for diagnostics and basic science applications, focusing in particular on the quantitative study of organ physiology at the microscopic scale. Recent advances pioneered by the laboratory include all-optical methods of blood flow quantification, imaging of cytoarchitecture and myeloarchitecture with intrinsic contrast, and statistical methods and models of capillary speed quantification. They have applied these tools to study a wide range of questions, from the basis of neurovascular coupling to evolution of injury and recovery in ischemic stroke.

  3. Quotes

    1. There are some subjective and structural methods available now for detecting glaucoma and its progression.
      In Second Catalyst Research Team Sets Sights on Biomarker Discovery