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Measurement of Retinal Blood Flow Using Fluorescently Labeled Red Blood Cells.

Kornfield TE, Newman EA - eNeuro (2015 Mar-Apr)

Bottom Line: The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs).Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels.We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455.

ABSTRACT

Blood flow is a useful indicator of the metabolic state of the retina. However, accurate measurement of retinal blood flow is difficult to achieve in practice. Most existing optical techniques used for measuring blood flow require complex assumptions and calculations. We describe here a simple and direct method for calculating absolute blood flow in vessels of all sizes in the rat retina. The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs). The accuracy of the blood flow measurements was verified by (1) comparing blood flow calculated independently using either flux or velocity combined with diameter measurements, (2) measuring total retinal blood flow in arterioles and venules, (3) measuring blood flow at vessel branch points, and (4) measuring changes in blood flow in response to hyperoxic and hypercapnic challenge. Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels. We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes.

No MeSH data available.


Related in: MedlinePlus

Blood flow calculated using two independent methods. Flow is calculated from fRBC flux (y-axis), and velocity and vessel cross-sectional area (x-axis). Each data point represents a single vessel. The red line represents unity.
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Figure 2: Blood flow calculated using two independent methods. Flow is calculated from fRBC flux (y-axis), and velocity and vessel cross-sectional area (x-axis). Each data point represents a single vessel. The red line represents unity.

Mentions: Blood flow was calculated by these two methods in vessels with a range of diameters and flow rates. The two methods yielded blood flow values that were highly correlated (Fig. 2; R2 = 0.982; p < 0.001; n = 15; Pearson linear correlation) with a slope deviating from unity by only 0.13. Because fRBC flux, blood velocity, blood vessel diameter, and blood cell counts are all measured independently, the highly correlative relationship between the flow values confirms the validity of our methods.


Measurement of Retinal Blood Flow Using Fluorescently Labeled Red Blood Cells.

Kornfield TE, Newman EA - eNeuro (2015 Mar-Apr)

Blood flow calculated using two independent methods. Flow is calculated from fRBC flux (y-axis), and velocity and vessel cross-sectional area (x-axis). Each data point represents a single vessel. The red line represents unity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465795&req=5

Figure 2: Blood flow calculated using two independent methods. Flow is calculated from fRBC flux (y-axis), and velocity and vessel cross-sectional area (x-axis). Each data point represents a single vessel. The red line represents unity.
Mentions: Blood flow was calculated by these two methods in vessels with a range of diameters and flow rates. The two methods yielded blood flow values that were highly correlated (Fig. 2; R2 = 0.982; p < 0.001; n = 15; Pearson linear correlation) with a slope deviating from unity by only 0.13. Because fRBC flux, blood velocity, blood vessel diameter, and blood cell counts are all measured independently, the highly correlative relationship between the flow values confirms the validity of our methods.

Bottom Line: The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs).Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels.We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455.

ABSTRACT

Blood flow is a useful indicator of the metabolic state of the retina. However, accurate measurement of retinal blood flow is difficult to achieve in practice. Most existing optical techniques used for measuring blood flow require complex assumptions and calculations. We describe here a simple and direct method for calculating absolute blood flow in vessels of all sizes in the rat retina. The method relies on ultrafast confocal line scans to track the passage of fluorescently labeled red blood cells (fRBCs). The accuracy of the blood flow measurements was verified by (1) comparing blood flow calculated independently using either flux or velocity combined with diameter measurements, (2) measuring total retinal blood flow in arterioles and venules, (3) measuring blood flow at vessel branch points, and (4) measuring changes in blood flow in response to hyperoxic and hypercapnic challenge. Confocal line scans oriented parallel and diagonal to vessels were used to compute fRBC velocity and to examine velocity profiles across the width of vessels. We demonstrate that these methods provide accurate measures of absolute blood flow and velocity in retinal vessels of all sizes.

No MeSH data available.


Related in: MedlinePlus