Laser speckle contrast imaging of blood flow in rat retinas using an endoscope

Ponticorvo, Adrien; Cardenas, Damon P.; Dunn, Andrew K.; Ts’o, Daniel Y.; Duong, Timothy Q.

doi:10.1117/1.jbo.18.9.090501

Cited by 40 publications

(24 citation statements)

References 21 publications

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“…Increased neural activity as induced by light stimulation leads to an increased metabolic demand and to hyperemia of the retina and the ONH. [50][51][52] Several techniques were used to assess the retinal blood flow response to flicker stimulation including laser speckle flowgraphy, [53][54][55] fluorescent microspheres, 8 the measurement of retinal vessel diameters, 56 and Doppler OCT. 57 Our results indicate that most of the increase in retinal blood flow is due to the increase in blood velocity, whereas retinal vessel diameters showed only minor changes. This is in good agreement with human data indicating that most of the vasodilator response occurs in the microvasculature.…”

Section: Discussionmentioning

confidence: 99%

Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

et al. 2014

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Abstract. A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Discussionmentioning

confidence: 99%

Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

et al. 2014

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“…To deliver the laser beam to the rat eye an endoscope (5 mm in diameter, 11.5 cm in length, Karl Storz 67260AA, Tuttlingen, Germany) was used [29]. The images were captured by a CMOS camera (acA1300-60gmNIR, Basler, Ahrensburg, Germany) with the following settings: recording rate of 50 frames per second, 800 × 800 pixel resolution, and 10 ms exposure time.…”

Section: Methodsmentioning

confidence: 99%

“…Flammer et al [27] explored the correlation between impaired ocular blood flow and glaucoma, while Watanabe et al [28] found that LSI technique is preferable to study choroidal blood flow in comparison with indocyanine green angiography. Ponticorvo et al performed LSI via en endoscope to record blood flow images from the rat retina [29]. In our earlier work [30] we applied LSI to estimate diameter changes and blood flow responses upon administration of acetylcholine, angiotensin II and changing levels of anesthesia.…”

Section: Introductionmentioning

confidence: 99%

Rat retinal vasomotion assessed by laser speckle imaging

et al. 2017

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Vasomotion is spontaneous or induced rhythmic changes in vascular tone or vessel diameter that lead to rhythmic changes in flow. While the vascular research community debates the physiological and pathophysiological consequence of vasomotion, there is a great need for experimental techniques that can address the role and dynamical properties of vasomotion in vivo. We apply laser speckle imaging to study spontaneous and drug induced vasomotion in retinal network of anesthetized rats. The results reveal a wide variety of dynamical patterns. Wavelet-based analysis shows that (i) spontaneous vasomotion occurs in anesthetized animals and (ii) vasomotion can be initiated by systemic administration of the thromboxane analogue U-46619 and the nitric-oxide donor S-nitroso-acetylDL-penicillamine (SNAP). Although these drugs activate different cellular pathways responsible for vasomotion, our approach can track the dynamical changes they cause.

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“…An IR Laser Module (LDM785, 785 nm, 20 mW, Thorlabs, Newton, New Jersey) was used as a laser source. An endoscope (5 mm of diameter, 11.5 cm of length, Karl Storz 67260AA, Tuttlingen, Germany) delivered laser light from the source to the rat eye [18]. A CMOS Camera (acA1300-60gmNIR, Basler, Ahrensburg, Germany (25 frames per second, 800 × 800 pixels, 5 ms of exposure time) recorded the signal.…”

Section: Methodsmentioning

confidence: 99%

Laser speckle analysis of retinal vascular dynamics

Neganova¹,

Postnov²,

Jacobsen³

et al. 2016

Biomed. Opt. Express

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Studies of vascular responses are usually performed on isolated vessels or on single vessels in vivo. This allows for precise measurements of diameter or blood flow. However, dynamical responses of the whole microvascular network are difficult to access experimentally. We suggest to use full-field laser speckle imaging to evaluate vascular responses of the retinal network. Image segmentation and vessel recognition algorithms together with response mapping allow us to analyze diameter changes and blood flow responses in the intact retinal network upon systemic administration of the vasoconstrictor angiotensin II, the vasodilator acetylcholine or on the changing level of anesthesia in in vivo rat preparations.

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Laser speckle contrast imaging of blood flow in rat retinas using an endoscope

Cited by 40 publications

References 21 publications

Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

Rat retinal vasomotion assessed by laser speckle imaging

Laser speckle analysis of retinal vascular dynamics

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