scholarly journals Quantitative hemodynamic analysis of cerebral blood flow and neurovascular coupling using optical coherence tomography angiography

2018 ◽  
Vol 39 (10) ◽  
pp. 1983-1994 ◽  
Author(s):  
Paul Shin ◽  
WooJhon Choi ◽  
JongYoon Joo ◽  
Wang-Yuhl Oh
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Laser Scanning ◽  
Neurovascular Coupling ◽  
Laser Scanning Microscopy ◽  
Oct Angiography ◽  
Wide Field ◽  
Optical Coherence ◽  
Arterial Blood ◽  
Doppler Oct

Functional hyperemia in the rat cortex was investigated using high-speed optical coherence tomography (OCT) angiography and Doppler OCT. OCT angiography (OCTA) was performed to image the hemodynamic stimulus-response over a wide field of view. Temporal changes in vessel diameters in different vessel compartments, which were determined as the diameters of erythrocyte flows in OCT angiograms, were measured in order to monitor localized hemodynamic changes. Our results showed that the dilation of arterioles at the site of activation was accompanied by the dilation of upstream arteries. Relatively negligible dilation was observed in veins. An increase in the OCTA signal was observed during stimulus in multiple capillaries, which may imply that capillary blood flow increases as a result of the expanded arterial blood volume. These results agree with previous observations using two-photon laser scanning microscopy (TPLSM). Doppler OCT was performed to quantitatively measure stimulus-induced blood flow response in pial arteries. The measurement showed small but clear hemodynamic response in upstream arteries with diameters exceeding 100 [Formula: see text]m. Our results demonstrate the potential of OCTA and Doppler OCT for the investigation of neurovascular coupling in small animal models.

scholarly journals Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

2012 ◽  
Vol 32 (7) ◽  
pp. 1277-1309 ◽  
Author(s):  
Andy Y Shih ◽  
Jonathan D Driscoll ◽  
Patrick J Drew ◽  
Nozomi Nishimura ◽  
Chris B Schaffer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Scanning ◽  
Vascular System ◽  
Neurovascular Coupling ◽  
Laser Scanning Microscopy ◽  
Small Scale ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Rats And Mice ◽  
The Brain

The cerebral vascular system services the constant demand for energy during neuronal activity in the brain. Attempts to delineate the logic of neurovascular coupling have been greatly aided by the advent of two-photon laser scanning microscopy to image both blood flow and the activity of individual cells below the surface of the brain. Here we provide a technical guide to imaging cerebral blood flow in rodents. We describe in detail the surgical procedures required to generate cranial windows for optical access to the cortex of both rats and mice and the use of two-photon microscopy to accurately measure blood flow in individual cortical vessels concurrent with local cellular activity. We further provide examples on how these techniques can be applied to the study of local blood flow regulation and vascular pathologies such as small-scale stroke.

scholarly journals Retinal blood flow reduction in normal-tension glaucoma with single-hemifield damage by Doppler optical coherence tomography

2020 ◽  
Vol 105 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Takafumi Yoshioka ◽  
Youngseok Song ◽  
Motofumi Kawai ◽  
Tomofumi Tani ◽  
Kengo Takahashi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Temporal Artery ◽  
Normal Tension Glaucoma ◽  
Retinal Nerve Fibre Layer ◽  
Retinal Blood Flow ◽  
Optical Coherence ◽  
Spectral Domain Oct ◽  
Blood Flow Reduction ◽  
Doppler Oct

AimsTo evaluate the associations between retinal blood flow (RBF) and optical coherence tomography (OCT) structural measurements in normal-tension glaucoma (NTG) eyes with single-hemifield visual field (VF) damage by the Doppler OCT.MethodsThe Doppler OCT was used to measure temporal artery (TA) RBF and temporal vein (TV) RBF. Retinal nerve fibre layer thickness (RNFLT) was measured by spectral-domain OCT.ResultsForty-three consecutive eyes of 43 patients with NTG with VF defect confined to a single hemifield and 24 eyes of 24 age-matched healthy subjects were studied. TA and TV RBF and RNFLT were reduced in the damaged hemisphere compared with the normal hemisphere (mean (SD), 3.61 (1.68) vs 5.86 (2.59) µL/min, p<0.001; 5.61 (2.51) vs 6.94 (2.83) µL/min, p=0.010; 69.0 (19.7) vs 99.7 (22.8) µm, p<0.001). Those values in the normal hemisphere of NTG eyes also decreased compared with the healthy hemisphere of the healthy eyes (8.40 (3.36) µL/min, p<0.001; 9.28 (4.47) µL/min, p<0.002; 122.8 (20.2) µm, p<0.001). Multivariate model showed that normal and damaged hemispheres and RNFLT were associated with RBF reduction. In addition, the RBF in the normal hemisphere was lower than that in the healthy hemisphere even after adjusting for RNFLT.ConclusionIn NTG eyes with single-hemifield damage, the RBF was significantly reduced in the damaged hemisphere compared with the normal one. The RBF decreased in the normal and damaged hemispheres of NTG eyes compared with the healthy hemisphere independent from RNFLT.

scholarly journals Assessing total retinal blood flow in diabetic retinopathy using multiplane en face Doppler optical coherence tomography

2017 ◽  
Vol 102 (1) ◽  
pp. 126-130 ◽  
Author(s):  
Alex D Pechauer ◽  
Thomas S Hwang ◽  
Ahmed M Hagag ◽  
Liang Liu ◽  
Ou Tan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Retinal Blood Flow ◽  
Optical Coherence ◽  
Data Set ◽  
Doppler Oct ◽  
Significant Difference ◽  
En Face ◽  
Doppler Optical Coherence Tomography

AimTo assess total retinal blood flow (TRBF) in diabetic retinopathy (DR) using multiplane en face Doppler optical coherence tomography (OCT).MethodsA 70 kHz spectral-domain OCT system scanned a 2×2 mm area centred at the optic disc of the eyes with DR and healthy participants. The multiplane en face Doppler OCT algorithm generated a three-dimensional volumetric data set consisting of 195 en face planes. The TRBF was calculated from the maximum flow values of each branching retinal vein at an optimised en face plane. DR severity was graded according to the international clinical classification system. The generalised linear model method was used to compare flow values between DR groups and the control group.ResultsA total of 71 eyes from 71 participants were included. Ten eyes were excluded due to poor image quality. The within-visit repeatability of scans was 4.1% (coefficient of variation). There was no significant difference in the TRBF between the healthy (46.7±10.2 µL/min) and mild/moderate non-proliferative DR (44.9±12.6 µL/min) groups. The TRBF in severe non-proliferative DR (39.1±12.6 µL/min) and proliferative DR (28.9±8.85 µL/min) groups were significantly lower (p=0.04 and p<0.0001, respectively) than that of the healthy group. TRBF was correlated with DR disease severity (p<0.0001, linear trend test).ConclusionThe novel multiplane en face Doppler OCT method provided reliable measurements of TRBF in DR eyes. This may be a useful tool in understanding the pathophysiology of DR.

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