Visualizing and quantifying the impact of reactive hyperemia on cutaneous microvessels in humans

2020 ◽  
Vol 128 (1) ◽  
pp. 17-24
Author(s):  
Raden Argarini ◽  
Kurt J. Smith ◽  
Howard H. Carter ◽  
Louise H. Naylor ◽  
Robert A. McLaughlin ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Flow Rate ◽  
Reactive Hyperemia ◽  
Assessment Tools ◽  
Clinical Settings ◽  
Optical Coherence ◽  
Doppler Flowmetry ◽  
Microvascular Changes ◽  
And Function ◽  
The Impact

The mechanisms underlying reactive hyperemia (RH) responses in microvessels are poorly understood. Previous assessment tools have not been capable of directly visualizing microvessels during physiological stimulation in humans. Optical coherence tomography (OCT) is capable of imaging and quantifying subcutaneous microvessels as small as ~30 µm. In this study we use OCT to visualize and quantify skin microvascular changes in response to RH for the first time in humans. We also assessed the reproducibility of this technique. OCT and laser Doppler flowmetry (LDF) were used simultaneously to scan cutaneous microvessels in 10 young healthy subjects on 2 days. We applied a speckle decorrelation algorithm to assess OCT images and calculated flow rate, speed, diameter, and density parameters. Measures were obtained at rest (baseline) and 30-s following a 5-min cuff inflation (RH). All data were compared between days. The RH stimulus significantly increased ( P < 0.0001) OCT-derived microvascular diameter (37.6 ± 3.4 vs. 44.5 ± 5.2 µm), flow rate (82.4 ± 23.4 vs. 240.1 ± 58.6 pl/s), speed (48 ± 5.7 vs. 101.5 ± 17.1 µm/s), density (5.1 ± 1.7 vs. 14.6 ± 2.6%), and also LDF-derived flux (12.3 ± 5.7 vs. 31.6 ± 9.1 perfusion units). At baseline, OCT-derived diameter ( r = 0.55), flow rate ( r = 0.64), speed ( r = 0.55), and density ( r = 0.75) showed significant between-day correlations ( P < 0.05), as did LDF results ( r = 0.74). In response to RH, OCT-derived diameter ( r = 0.63) and density ( r = 0.64) showed significant correlations ( P < 0.05), whereas flow rate ( r = 0.45), speed ( r = 0.43), and LDF ( r = 0.26) were less reproducible. Our study is novel in that it establishes the feasibility of using OCT to visualize and quantify microvascular structure and function responses to RH in humans. NEW & NOTEWORTHY This study describes the first evidence in humans that optical coherence tomography provides direct visualization and comprehensive quantification of cutaneous microvascular hemodynamics as a response to reactive hyperemia. This imaging technique will greatly improve human cutaneous microvascular assessment in physiological and clinical settings.

scholarly journals Identification of Retinal Biomarkers in Alzheimer’s Disease Using Optical Coherence Tomography: Recent Insights, Challenges, and Opportunities

2019 ◽  
Vol 8 (7) ◽  
pp. 996 ◽  
Author(s):  
Delia Cabrera DeBuc ◽  
Magdalena Gaca-Wysocka ◽  
Andrzej Grzybowski ◽  
Piotr Kanclerz
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Coherence Tomography ◽  
Retinal Blood Flow ◽  
Optical Coherence ◽  
Ocular Diseases ◽  
Challenges And Opportunities ◽  
Retinal Structure ◽  
And Function ◽  
The Impact

This review will highlight recent insights into measuring retinal structure in Alzheimer’s disease (AD). A growing body of evidence indicates that disturbances in retinal blood flow and structure are related to cognitive function, which can severely impair vision. Optical coherence tomography (OCT) is an optical imaging technology that may allow researchers and physicians to gain deeper insights into retinal morphology and clarify the impact of AD on retinal health and function. Direct and noninvasive measurement of retinal morphology using OCT has provided useful diagnostic and therapeutic indications in several central nervous system (CNS) diseases, including AD, multiple sclerosis, and Parkinson disease. Despite several limitations, morphology assessment in the retinal layers is a significant advancement in the understanding of ocular diseases. Nevertheless, additional studies are required to validate the use of OCT in AD and its complications in the eye.

scholarly journals Optical coherence tomography: a novel imaging approach to visualize and quantify cutaneous microvascular structure and function in patients with diabetes

2020 ◽  
Vol 8 (1) ◽  
pp. e001479
Author(s):  
Raden Argarini ◽  
Robert A McLaughlin ◽  
Simon Z Joseph ◽  
Louise H Naylor ◽  
Howard H Carter ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Flow Rate ◽  
Local Heating ◽  
Microvascular Disease ◽  
Structure And Function ◽  
Optical Coherence ◽  
Local Skin ◽  
Patients With Diabetes ◽  
And Function

IntroductionThe pathophysiology of microvascular disease is poorly understood, partly due to the lack of tools to directly image microvessels in vivo.Research design and methodsIn this study, we deployed a novel optical coherence tomography (OCT) technique during local skin heating to assess microvascular structure and function in diabetics with (DFU group, n=13) and without (DNU group, n=10) foot ulceration, and healthy controls (CON group, n=13). OCT images were obtained from the dorsal foot, at baseline (33°C) and 30 min following skin heating.ResultsAt baseline, microvascular density was higher in DFU compared with CON (21.9%±11.5% vs 14.3%±5.6%, p=0.048). Local heating induced significant increases in diameter, speed, flow rate and density in all groups (all p<0.001), with smaller changes in diameter for the DFU group (94.3±13.4 µm), compared with CON group (115.5±11.7 µm, p<0.001) and DNU group (106.7±12.1 µm, p=0.014). Heating-induced flow rate was lower in the DFU group (584.3±217.0 pL/s) compared with the CON group (908.8±228.2 pL/s, p<0.001) and DNU group (768.8±198.4 pL/s, p=0.014), with changes in density also lower in the DFU group than CON group (44.7%±15.0% vs 56.5%±9.1%, p=0.005).ConclusionsThis proof of principle study indicates that it is feasible to directly visualize and quantify microvascular function in people with diabetes; and distinguish microvascular disease severity between patients.

scholarly journals Assessing the impact of aging and blood pressure on dermal microvasculature by reactive hyperemia optical coherence tomography angiography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael Wang-Evers ◽  
Malte J. Casper ◽  
Joshua Glahn ◽  
Tuanlian Luo ◽  
Abigail E. Doyle ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Optical Coherence Tomography ◽  
High Blood Pressure ◽  
Optical Coherence Tomography Angiography ◽  
Reactive Hyperemia ◽  
Optical Coherence ◽  
Physiological Factors ◽  
Non Invasive ◽  
Histological Images ◽  
The Impact

AbstractVisualization and quantification of the skin microvasculature are important for studying the health of the human microcirculation. We correlated structural and pathophysiological changes of the dermal capillary-level microvasculature with age and blood pressure by using the reactive hyperemia optical coherence tomography angiography (RH-OCT-A) technique and evaluated both conventional OCT-A and the RH-OCT-A method as non-invasive imaging alternatives to histopathology. This observational pilot study acquired OCT-A and RH-OCT-A images of the dermal microvasculature of 13 young and 12 old healthy Caucasian female subjects. Two skin biopsies were collected per subject for histological analysis. The dermal microvasculature in OCT-A, RH-OCT-A, and histological images were automatically quantified and significant indications of vessel rarefaction in both old subjects and subjects with high blood pressure were observed by RH-OCT-A and histopathology. We showed that an increase in dermal microvasculature perfusion in response to reactive hyperemia was significantly lower in high blood pressure subjects compared to normal blood pressure subjects (117% vs. 229%). These results demonstrate that RH-OCT-A imaging holds functional information of the microvasculature with respect to physiological factors such as age and blood pressure that may help to monitor early disease progression and assess overall vascular health. Additionally, our results suggest that RH-OCT-A images may serve as a non-invasive alternative to histopathology for vascular analysis.

scholarly journals The role of optical coherence tomography guidance in scaffold versus stent optimization

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Arif A. Al Nooryani ◽  
Nagwa A. Abdelrahman ◽  
Hatem A. Helmy ◽  
Yehia T. Kishk ◽  
Ayman K. M. Hassan
Keyword(s):  
Decision Making ◽  
Optical Coherence Tomography ◽  
Coronary Intervention ◽  
Drug Eluting Stents ◽  
Optical Coherence ◽  
Total Rate ◽  
Great Ability ◽  
Bioresorbable Scaffolds ◽  
Drug Eluting ◽  
The Impact

Abstract Background Optical coherence tomography showed a great ability to identify adverse features during percutaneous coronary intervention with drug-eluting stents and resulted in better clinical outcomes. The study aimed to assess the impact of optical coherence tomography on intraoperative decision-making during implantation of Absorb bioresorbable scaffolds versus everolimus drug-eluting stents. Results We performed an observational study that included 223 consecutive patients post optical coherence tomography-guided implantation of either Absorb bioresorbable scaffolds (162 patients) or everolimus drug-eluting stents (61 patients). We studied the influence of optical coherence tomography on intraoperative decision-making during implantation of bioresorbable scaffolds versus drug-eluting stents by analyzing the total rate of optical coherence tomography-dependent modifications in each device. After satisfactory angiographic results, the total rate of required intervention for optical coherence tomography detected complications was significantly higher in the bioresorbable scaffolds arm compared to drug-eluting stents arm (47.8% versus 32.9%, respectively; p = 0.019). The additional modifications encompassed further optimization in the case of device underexpansion or struts malapposition, and even stenting in the case of strut fractures, or significant edge dissection. Conclusions Compared to drug-eluting stents, Absord scaffold was associated with a significantly higher rate of optical coherence tomography-identified intraprocedural complications necessitating further modifications. The study provides some hints on the reasons of scaffolds failure in current PCI practice; it offers a new insight for the enhancement of BRS safety and presents and adds to the growing literature for successful BRS utilization.

scholarly journals Modern Diagnostic Techniques for the Assessment of Ocular Blood Flow in Myopia: Current State of Knowledge

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ewa Grudzińska ◽  
Monika Modrzejewska
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Refractive Error ◽  
Retinal Vessel ◽  
Ocular Blood Flow ◽  
Laser Speckle ◽  
Doppler Imaging ◽  
Optical Coherence ◽  
Contrast Imaging ◽  
Doppler Flowmetry

Myopia is the most common refractive error and the subject of interest of various studies assessing ocular blood flow. Increasing refractive error and axial elongation of the eye result in the stretching and thinning of the scleral, choroid, and retinal tissues and the decrease in retinal vessel diameter, disturbing ocular blood flow. Local and systemic factors known to change ocular blood flow include glaucoma, medications and fluctuations in intraocular pressure, and metabolic parameters. Techniques and tools assessing ocular blood flow include, among others, laser Doppler flowmetry (LDF), retinal function imager (RFI), laser speckle contrast imaging (LSCI), magnetic resonance imaging (MRI), optical coherence tomography angiography (OCTA), pulsatile ocular blood flowmeter (POBF), fundus pulsation amplitude (FPA), colour Doppler imaging (CDI), and Doppler optical coherence tomography (DOCT). Many researchers consistently reported lower blood flow parameters in myopic eyes regardless of the used diagnostic method. It is unclear whether this is a primary change that causes secondary thinning of ocular tissues or quite the opposite; that is, the mechanical stretching of the eye wall reduces its thickness and causes a secondary lower demand of tissues for oxygen. This paper presents a review of studies assessing ocular blood flow in myopes.

Sign in / Sign up

Export Citation Format

Share Document