Scattering-Angle-Resolved Optical Coherence Tomography of a Hypoxic Mouse Retina Model

Several studies have noted a correlation between retinal degeneration and traumatic encephalopathy (TE) making the retina a leading candidate for detection and assessment. Scattering-angle-resolved optical coherence tomography (SAR-OCT) is a candidate imaging modality to detect sub-resolution changes in retinal microstructure. SAR-OCT images of murine retinas that experience a hypoxic insult—euthanasia by isoflurane overdose—are presented. A total of 4 SAR-OCT measurement parameters are reported in 6 longitudinal experiments: blood flow volume fraction, total retinal thickness, reflectance index, and scattering angle. As each mouse expires, blood flow volume fraction decreases, total retinal thickness increases, reflectance index decreases, and scattering angle diversity increases. Contribution of the retinal vasculature to scattering angle diversity is discussed. Results of this study suggest the utility of SAR-OCT to measure TE using scattering angle diversity contrast in the retina.

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Phase-resolved optical coherence tomography and optical Doppler tomography for imaging blood flow in human skin with fast scanning speed and high velocity sensitivity

Optics Letters ◽

10.1364/ol.25.000114 ◽

2000 ◽

Vol 25 (2) ◽

pp. 114 ◽

Cited By ~ 447

Author(s):

Yonghua Zhao ◽

Zhongping Chen ◽

Christopher Saxer ◽

Shaohua Xiang ◽

Johannes F. de Boer ◽

...

Keyword(s):

Blood Flow ◽

Optical Coherence Tomography ◽

Human Skin ◽

High Velocity ◽

Scanning Speed ◽

Optical Coherence ◽

Doppler Tomography ◽

Velocity Sensitivity ◽

Optical Doppler Tomography

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Blood Vessel Density Measured Using Dynamic Optical Coherence Tomography is a Tool for Wound Healers

The International Journal of Lower Extremity Wounds ◽

10.1177/15347346211017334 ◽

2021 ◽

pp. 153473462110173

Author(s):

Rajgopal Mani ◽

Jon Holmes ◽

Kittipan Rerkasem ◽

Nikolaos Papanas

Keyword(s):

Blood Flow ◽

Optical Coherence Tomography ◽

Blood Vessel ◽

Chronic Wounds ◽

Vessel Density ◽

Optical Coherence ◽

Skin Microcirculation ◽

Wound Edge ◽

Venous Ulcers ◽

Oct Imaging

Dynamic optical coherence tomography (D-OCT) is a relatively new technique that may be used to study the substructures in the retina, in the skin and its microcirculation. Furthermore, D-OCT is a validated method of imaging blood flow in skin microcirculation. The skin around venous and mixed arterio-venous ulcers was imaged and found to have tortuous vessels assumed to be angiogenic sprouts, and classified as dots, blobs, coils, clumps, lines, and curves. When these images were analyzed and measurements of vessel density were made, it was observed that the prevalence of coils and clumps in wound borders was significantly greater compared with those at wound centers. This reinforced the belief of inward growth of vessels from wound edge toward wound center which, in turn, reposed confidence in following the wound edge to study healing. D-OCT imaging permits the structure and the function of the microcirculation to be imaged, and vessel density measured. This offers a new vista of skin microcirculation and using it, to better understand angiogenesis in chronic wounds.

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Visualization of three-dimensional microcirculation of rodents’ retina and choroid for studies of critical illness using optical coherence tomography angiography

Scientific Reports ◽

10.1038/s41598-021-93631-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jang Ryul Park ◽

ByungKun Lee ◽

Min Ji Lee ◽

Kyuseok Kim ◽

Wang-Yuhl Oh

Keyword(s):

Blood Flow ◽

Optical Coherence Tomography ◽

Severe Sepsis ◽

Critical Illness ◽

Hemorrhagic Shock ◽

Optical Coherence Tomography Angiography ◽

Flow Index ◽

Optical Coherence ◽

Sepsis Model ◽

Lactate Levels

AbstractWe developed a method to measure the relative blood flow speed using optical coherence tomography angiography (OCTA) in retina and choroid, and investigated the feasibility of this method for assessing microcirculatory function in rat models of sepsis and hemorrhagic shock. Two sepsis models, 6-h severe sepsis without treatment and 30-h moderate sepsis maintaining mean arterial pressure, and volume controlled hemorrhagic shock and fluid resuscitation model were used to see the change of microcirculation. The blood flow index (BFI), which was calculated from the OCTA images to represent the average relative blood flow, was decreasing during the 6-h severe sepsis model. Its change is in parallel with the mean arterial blood pressure (MAP) and blood lactate levels. In the 30-h moderate sepsis model, the BFI was decreased while maintaining MAP, and lactate was increased. In the hemorrhagic shock model, the change of BFI is in line with MAP and lactate levels. In all models, BFI change is more sensitive in choroid than in retina. This study presents the OCTA-based retinal and choroidal microcirculatory blood flow monitoring method and shows its utility for assessment of critical illness.

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Retinal Optical Coherence Tomography Metrics Are Unchanged in Verubecestat Alzheimer’s Disease Clinical Trial but Correlate with Baseline Regional Brain Atrophy

Journal of Alzheimer s Disease ◽

10.3233/jad-200735 ◽

2021 ◽

Vol 79 (1) ◽

pp. 275-287

Author(s):

Robert C. Sergott ◽

Annaswamy Raji ◽

James Kost ◽

Cyrille Sur ◽

Saheeda Jackson ◽

...

Keyword(s):

Clinical Trial ◽

Optical Coherence Tomography ◽

Nerve Fiber ◽

Retinal Nerve Fiber Layer ◽

Brain Atrophy ◽

Retinal Thickness ◽

Optical Coherence ◽

Fiber Layer ◽

Nerve Fiber Layer ◽

Retinal Nerve Fiber

Background: We performed exploratory analyses of retinal thickness data from a clinical trial of the AβPP cleaving enzyme (BACE) inhibitor verubecestat in patients with Alzheimer’s disease (AD). Objective: To evaluate: 1) possible retinal thickness changes following BACE inhibition; and 2) possible association between retinal thickness and brain atrophy. Methods: Retinal thickness was measured using spectral-domain optical coherence tomography in a 78-week randomized placebo-controlled trial of verubecestat in 1,785 patients with mild-to-moderate AD. Changes from baseline in retinal pigment epithelium, macular grid retinal nerve fiber layer, central subfield retinal thickness, and macular grid volume were evaluated for verubecestat versus placebo. Correlation analyses were performed to investigate the potential association between macular grid retinal nerve fiber layer and central subfield retinal thickness with brain volumetric magnetic resonance imaging (vMRI) data at baseline, as well as correlations for changes from baseline at Week 78 in patients receiving placebo. Results: Verubecestat did not significantly alter retinal thickness during the trial compared with placebo. At baseline, mean macular grid retinal nerve fiber layer and central subfield retinal thickness were weakly but significantly correlated (Pearson’s r values≤0.23, p-values < 0.01) with vMRI of several brain regions including whole brain, hippocampus, and thalamus. At Week 78, correlations between retinal thickness and brain vMRI changes from baseline in the placebo group were small and mostly not statistically significant. Conclusion: BACE inhibition by verubecestat was not associated with adverse effects on retinal thickness in patients with mild-to-moderate AD. Correlations between retinal thickness and brain volume were observed at baseline. Trial registration: Clinicaltrials.gov NCT01739348 (registered December 3, 2012; https://clinicaltrials.gov/ct2/show/NCT01739348).

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