1. 1-9 of 9
    1. Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      An automated massive histology setup combined with an optical coherence tomography (OCT) microscope was used to image a total of n = 5 n=5 whole mouse brains. Each acquisition generated a dataset of thousands of OCT volumetric tiles at a sampling resolution of 4.9 × 4.9 × 6.5    μ m 4.9×4.9×6.5  μm . This paper describes techniques for reconstruction and segmentation of the sliced brains. In addition to the measured OCT optical reflectivity, a single scattering photon model was used to compute the attenuation coefficients within each tissue slice. Average mouse brain templates were generated for ...

      Read Full Article
    2. Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of ...

      Read Full Article
    3. Visualizing and mapping the cerebellum with serial optical coherence scanner

      Visualizing and mapping the cerebellum with serial optical coherence scanner

      We present the visualization of the mouse cerebellum and adjacent brainstem using a serial optical coherence scanner, which integrates a vibratome slicer and polarization-sensitive optical coherence tomography for ex vivo imaging. The scanner provides intrinsic optical contrasts to distinguish the cerebellar cortical layers and white matter. Images from serial scans reveal the large-scale anatomy in detail and map the nerve fiber pathways in the cerebellum and brainstem. By incorporating a water-immersion microscope objective, we also present high-resolution tiled images that delineate fine structures in the cerebellum and brainstem.

      Read Full Article
    4. Review of optical coherence tomography based angiography in neuroscience

      Review of optical coherence tomography based angiography in neuroscience

      The brain is a complex ecosystem, consisting of multiple layers and tissue compartments. To facilitate the understanding of its function and its response to neurological insults, a fast in vivo imaging tool with a micron-level resolution, which can provide a field of view at a few millimeters, is desirable. Optical coherence tomography (OCT) is a noninvasive method for imaging three-dimensional biological tissues with high resolution ( ∼ 10    μ m ∼10  μm ) and without a need for contrast agents. Recent development of OCT-based angiography has started to shed some new light on cerebral hemodynamics in neuroscience. We give an overview of the recent ...

      Read Full Article
    5. Optical coherence tomography for cross-sectional imaging of neural activity

      Optical coherence tomography for cross-sectional imaging of neural activity

      Abstract. We report a functional optical coherence tomography cross-sectional scanner to detect neural activity using unmyelinated nerves dissected from squid. The nerves, unstained or stained with a voltage-sensitive dye, were imaged in a nerve chamber. Transient phase changes from backscattered light were detected during action potential propagation. The results show that the scanner can provide high spatiotemporal resolution cross-sectional images of neural activity ( 15     μ s / A - line ; 0.25     ms / B - scan ; ∼ 8.5 × 5.5     μ m 2 in x z ). The advantage of this method compared to monitoring a single depth profile z is a dramatic increase in the ...

      Read Full Article
    6. Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke

      Vasodynamics of pial and penetrating arterioles in relation to arteriolo-arteriolar anastomosis after focal stroke

      Changes in blood perfusion in highly interconnected pial arterioles provide important insights about the vascular response to ischemia within brain. The functional role of arteriolo-arteriolar anastomosis (AAA) in regulating blood perfusion through penetrating arterioles is yet to be discovered. We apply a label-free optical microangiography (OMAG) technique to evaluate the changes in vessel lumen diameter and red blood cell velocity among a large number of pial and penetrating arterioles within AAA abundant region overlaying the penumbra in the parietal cortex after a middle cerebral artery occlusion (MCAO). In comparison with two-photon microscopy, the OMAG technique makes it possible to image ...

      Read Full Article
    7. Multimodal reconstruction of microvascular-flow distributions using combined two-photon microscopy and Doppler optical coherence tomography

      Multimodal reconstruction of microvascular-flow distributions using combined two-photon microscopy and Doppler optical coherence tomography

      Computing microvascular cerebral blood flow ( μ CBF ) in real cortical angiograms is challenging. Here, we investigated whether the use of Doppler optical coherence tomography (DOCT) flow measurements in individual vessel segments can help in reconstructing μ CBF across the entire vasculature of a truncated cortical angiogram. A μ CBF computational framework integrating DOCT measurements is presented. Simulations performed on a synthetic angiogram showed that the addition of DOCT measurements, especially close to large inflowing or outflowing vessels, reduces the impact of pressure boundary conditions and estimated vessel resistances resulting in a more accurate reconstruction of μ CBF . Our technique was then applied to reconstruct ...

      Read Full Article
    8. Optical coherence tomography visualizes neurons in human entorhinal cortex

      Optical coherence tomography visualizes neurons in human entorhinal cortex

      The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50     μ m in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images ...

      Read Full Article
    9. Decreased light attenuation in cerebral cortex during cerebral edema detected using optical coherence tomography

      Decreased light attenuation in cerebral cortex during cerebral edema detected using optical coherence tomography

      Cerebral edema develops in response to a variety of conditions, including traumatic brain injury and stroke, and contributes to the poor prognosis associated with these injuries. This study examines the use of optical coherence tomography (OCT) for detecting cerebral edema in vivo . Three-dimensional imaging of an in vivo water intoxication model in mice was performed using a spectral-domain OCT system centered at 1300 nm. The change in attenuation coefficient was calculated and cerebral blood flow was analyzed using Doppler OCT techniques. We found that the average attenuation coefficient in the cerebral cortex decreased over time as edema progressed. The initial ...

      Read Full Article
    1-9 of 9
  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