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Compact Laser Doppler Flowmeter (LDF) Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.

Mentek M, Truffer F, Chiquet C, Godin-Ribuot D, Amoos S, Loeuillet C, Bernabei M, Geiser M - PLoS ONE (2015)

Bottom Line: Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).Inter-day reproducibility was good (0.79 and 0.7, respectively).Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

View Article: PubMed Central - PubMed

Affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.

ABSTRACT

Purpose: Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH), choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).

Methods: A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day) of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats).

Results: The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively) indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively). Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

Conclusion: We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.

No MeSH data available.


Related in: MedlinePlus

Linearity assessment of LDF parameters.Ocular blood perfusion parameters Vol (volume) and Vel (velocity) versus the velocity obtained from a rotating Teflon (A) wheel and a flow of microspheres in a glass capillary (B).
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pone.0134378.g003: Linearity assessment of LDF parameters.Ocular blood perfusion parameters Vol (volume) and Vel (velocity) versus the velocity obtained from a rotating Teflon (A) wheel and a flow of microspheres in a glass capillary (B).

Mentions: The results of the LDF measurements recorded using the Teflon wheel and latex microspheres are shown in Fig 3. Vel varied linearly with the velocity of the wheel (Pearson correlation factor, 0.999, p < 0.0001). Vol remained constant over the range of induced velocity (0.232 ± 0.007 a.u., Fig 3A). Due to the minimum voltage required to operate the motor, velocities lower than 5 mm/s could not be tested. Similar results were obtained using flowing microspheres: Vel varied linearly with the velocity of the microspheres in the capillary (Pearson correlation factor, 0.998, p < 0.0001). Vol remained constant (0.258 ± 0.001 a.u., Fig 3B). DC (data not shown) remained constant in both setups over the entire velocity range (Teflon wheel 0.359 ± 0.001 Volt and microspheres 0.338 ± 0.004 Volt).


Compact Laser Doppler Flowmeter (LDF) Fundus Camera for the Assessment of Retinal Blood Perfusion in Small Animals.

Mentek M, Truffer F, Chiquet C, Godin-Ribuot D, Amoos S, Loeuillet C, Bernabei M, Geiser M - PLoS ONE (2015)

Linearity assessment of LDF parameters.Ocular blood perfusion parameters Vol (volume) and Vel (velocity) versus the velocity obtained from a rotating Teflon (A) wheel and a flow of microspheres in a glass capillary (B).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520556&req=5

pone.0134378.g003: Linearity assessment of LDF parameters.Ocular blood perfusion parameters Vol (volume) and Vel (velocity) versus the velocity obtained from a rotating Teflon (A) wheel and a flow of microspheres in a glass capillary (B).
Mentions: The results of the LDF measurements recorded using the Teflon wheel and latex microspheres are shown in Fig 3. Vel varied linearly with the velocity of the wheel (Pearson correlation factor, 0.999, p < 0.0001). Vol remained constant over the range of induced velocity (0.232 ± 0.007 a.u., Fig 3A). Due to the minimum voltage required to operate the motor, velocities lower than 5 mm/s could not be tested. Similar results were obtained using flowing microspheres: Vel varied linearly with the velocity of the microspheres in the capillary (Pearson correlation factor, 0.998, p < 0.0001). Vol remained constant (0.258 ± 0.001 a.u., Fig 3B). DC (data not shown) remained constant in both setups over the entire velocity range (Teflon wheel 0.359 ± 0.001 Volt and microspheres 0.338 ± 0.004 Volt).

Bottom Line: Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).Inter-day reproducibility was good (0.79 and 0.7, respectively).Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

View Article: PubMed Central - PubMed

Affiliation: HP2 laboratory, Grenoble Alpes University, 38000, Grenoble, France; INSERM U1042 laboratory, 38000, Grenoble, France.

ABSTRACT

Purpose: Noninvasive techniques for ocular blood perfusion assessment are of crucial importance for exploring microvascular alterations related to systemic and ocular diseases. However, few techniques adapted to rodents are available and most are invasive or not specifically focused on the optic nerve head (ONH), choroid or retinal circulation. Here we present the results obtained with a new rodent-adapted compact fundus camera based on laser Doppler flowmetry (LDF).

Methods: A confocal miniature flowmeter was fixed to a specially designed 3D rotating mechanical arm and adjusted on a rodent stereotaxic table in order to accurately point the laser beam at the retinal region of interest. The linearity of the LDF measurements was assessed using a rotating Teflon wheel and a flow of microspheres in a glass capillary. In vivo reproducibility was assessed in Wistar rats with repeated measurements (inter-session and inter-day) of retinal arteries and ONH blood velocity in six and ten rats, respectively. These parameters were also recorded during an acute intraocular pressure increase to 150 mmHg and after heart arrest (n = 5 rats).

Results: The perfusion measurements showed perfect linearity between LDF velocity and Teflon wheel or microsphere speed. Intraclass correlation coefficients for retinal arteries and ONH velocity (0.82 and 0.86, respectively) indicated strong inter-session repeatability and stability. Inter-day reproducibility was good (0.79 and 0.7, respectively). Upon ocular blood flow cessation, the retinal artery velocity signal substantially decreased, whereas the ONH signal did not significantly vary, suggesting that it could mostly be attributed to tissue light scattering.

Conclusion: We have demonstrated that, while not adapted for ONH blood perfusion assessment, this device allows pertinent, stable and repeatable measurements of retinal blood perfusion in rats.

No MeSH data available.


Related in: MedlinePlus