Mapping of flow velocity using spatiotemporal changes in time‐intensity curves from indocyanine green videoangiography

Niizawa, Tomoya; Hachiya, Ryota; Sugashi, Takuma; Terao, Shuji; Nagai, Mutsumi; Ishikawa, Mami

doi:10.1111/micc.12685

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…Space‐time diagrams of image contrast changes along manually tracing vessels have been proposed to determine two‐dimensional (2D) spatial patterns of RBC flow velocity 12 . Previously, we developed an image‐based flow mapping method with automatic extraction of vessel centerlines from fluorescent microvascular images in animal and human brains under neurosurgery 13,14 . The developed algorithm can be used to automatically extract capillary loops for NVC and to visualize the 2D distribution of capillary diameters, flow velocity, and temporal fluctuations of the flow.…”

Section: Introductionmentioning

confidence: 99%

“…12 Previously, we developed an image-based flow mapping method with automatic extraction of vessel centerlines from fluorescent microvascular images in animal and human brains under neurosurgery. 13,14 The developed algorithm can be used to automatically extract capillary loops for NVC and to visualize the 2D distribution of capillary diameters, flow velocity, and temporal fluctuations of the flow. The automated analysis method is required to avoid subjective bias in capillary selection and to expand the use of NVC in large population group studies.…”

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confidence: 99%

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Automated capillary flow segmentation and mapping for nailfold video capillaroscopy

et al. 2022

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Objective This study aimed to develop an automated image analysis method for segmentation and mapping of capillary flow dynamics captured using nailfold video capillaroscopy (NVC). Methods were applied to compare capillary flow structures and dynamics between young and middle‐aged healthy controls. Methods NVC images were obtained in a resting state, and a region of the vessel in the image was extracted using a conventional U‐Net neural network. The approximate length, diameter, and radius of the curvature were calculated automatically. Flow speed and its fluctuation over time were mapped using the Radon transform and frequency spectrum analysis from the kymograph image created along the vessel's centerline. Results The diameter of the curve segment (14.4 μm and 13.0 μm) and the interval of two straight segments (13.7 μm and 32.1 μm) of young and middle‐aged subjects, respectively, were significantly different. Faster flow was observed in older subjects (0.48 mm/s) than in younger subjects (0.26 mm/s). The power spectral analysis revealed a significant correlation between the high‐frequency power spectrum and the flow speed. Conclusions The present method allows a spatiotemporal characterization of capillary morphology and flow dynamics with NVC, allowing a wide application such as large‐scale health assessment.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Automated capillary flow segmentation and mapping for nailfold video capillaroscopy

et al. 2022

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“…The time-dependent change in image intensity is referred to as the time-intensity curve (TIC). Niizawa et al used TIC from indocyanine green videoangiography to estimate arterial and venous flow velocity in patients (6).…”

Section: Introductionmentioning

confidence: 99%

Comparing the Effect of Helical-centerline Stent Placement on Blood Flow Velocity with a Straight Stent

Kohata

Anzai

Ohta

2022

Preprint

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Stent treatment can be used to treat blood vessel stenosis in a less invasive manner, but re-stenosis is a concern. Because a helical-stent configuration has been thought to reduce the amount of intimal hyperplasia, the helical stent is considered clinically effective. The effects of the helical stent on blood flow velocity, however, have not been studied. In this study, we estimated flow velocities before and after helical stenting using time-intensity-curve (TIC) from angiography images and compared them with straight stenting velocities. As a result, in all cases (N = 3), the velocity reduction was less with helical stenting than with straight stenting. Based on angiography images, this flow estimation method can estimate patient-specific blood flow velocity in situ even in a presence of a stent.

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Quantitative study of spatial and temporal variation in retinal capillary network perfusion in rat eye by in vivo confocal imaging

Yu,

Mehnert,

Dickson

et al. 2023

Sci Rep

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Microvascular dysfunction is the underlying pathological process in many systemic diseases. However, investigation into its pathogenesis is impeded by the accessibility and complexity of the microvasculature within different organs, particularly for the central nervous system. The retina as an extension of the cerebrum provides a glimpse into the brain through which the microvasculature can be observed. Two major questions remain unanswered: How do the microvessels regulate spatial and temporal delivery to satisfy the varying cellular demands, and how can we quantify blood perfusion in the 3D capillary network? Here, quantitative measurements of red blood cell (RBC) speed in each vessel in the field were made in the in vivo rat retinal capillary network using an ultrafast confocal technique with fluorescently labelled RBCs. Retinal RBC speed and number were found to vary remarkably between microvessels ranging from 215 to 6641 microns per second with significant variations spatially and temporally. Overall, the RBC speed was significantly faster in the microvessels in the superficial retina than in the deep retina (estimated marginal means of 2405 ± 238.2 µm/s, 1641 ± 173.0 µm/s respectively). These observations point to a highly dynamic nature of microvasculature that is specific to its immediate cellular environment and is constantly changing.

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Mapping of flow velocity using spatiotemporal changes in time‐intensity curves from indocyanine green videoangiography

Cited by 4 publications

References 18 publications

Automated capillary flow segmentation and mapping for nailfold video capillaroscopy

Automated capillary flow segmentation and mapping for nailfold video capillaroscopy

Comparing the Effect of Helical-centerline Stent Placement on Blood Flow Velocity with a Straight Stent

Quantitative study of spatial and temporal variation in retinal capillary network perfusion in rat eye by in vivo confocal imaging

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