In vivo OCT microangiography of rodent iris

Abstract

We report on the functional optical coherence tomography (OCT) imaging of iris tissue morphology and microcirculation in living small animals. Anterior segments of healthy mouse and rat eyes are imaged with high-speed spectral domain OCT (SD-OCT) utilizing ultra-high sensitive optical microangiography (UHS-OMAG) imaging protocol. 3D iris microvasculature is produced by the use of an algorithm that calculates absolute differences between the amplitudes of the OCT inter-frames. We demonstrate that the UHS-OMAG is capable of delineating iris microvascular beds in the mouse and rat with capillary-level resolution. Furthermore, the fast imaging speed enables dynamic imaging of iris micro-vascular response during drug-induced pupil dilation. We believe that this OCT angiographic approach has a great potential for in situ and in vivo monitoring of the microcirculation within iris tissue beds in rodent disease models that have microvascular involvement.

Cerebral capillary velocimetry based on temporal OCT speckle contrast

“…2(a), which was 99 ensemble averaged. OCTA technique used was an intensity optical microangiography (OMAG) based on absolute of subtraction between inter B-frames to obtain RBC motion contrast for visualizing the functional vessels [26]. Binarization was then performed on the OCTA image with thresholding ( Fig.…”

Optical coherence tomography based microangiography for quantitative monitoring of structural and vascular changes in a rat model of acute uveitisin vivo: a preliminary study

“…An anterior OCT system was used to implement OMAG, which was the system previously described in Ref. 31. In brief, it was a custom-built spectral-domain OCT system operated at a central wavelength of 1340 nm with a scan speed of 92,000 A lines per second.…”

“…B-mode blood flow images were computed from the acquired 3-D OCT data volume by applying an intensity-based OCT angiography algorithm. 31 In this method, the intensity changes in time caused by randomly backscattered lights resulting from moving red blood cells in the vessel lumens can be decoupled from the surrounding static tissue regions by subtraction of adjacent two B-frames (a time interval of 7 ms) obtained at the same location, representing blood perfusion in the functional vessels. This strategy to contrast blood flow is quite similar to ultrahigh-sensitive optical microangiography, 25,26 an OMAG algorithm that utilizes the analytical forms of the OCT signals rather than the OCT amplitude signals.…”

“…This angiographic modality was able to delineate functional microvasculature in the anterior segment tissue beds of the rat eyes in vivo. 31 Figure 5 shows microvascular imaging results for the rat without steroid treatment. An en face (XY) OMAG (3.57 mm × 3.57 mm) To quantify the amount of vascular dilation that occurs with inflammation, we compared iris vessel diameters at the same location for the pre and postinjection OMAG angiograms.…”

Feasibility of correlation mapping optical coherence tomography angiographic technique using a 200 kHz vertical-cavity surface-emitting laser source for in vivo microcirculation imaging applications

“…The 3D volume data was acquired in 27 s. Figure 6 shows the results of the experiment. Figure 6 It can be seen that the cmOCT is capable of being applied to high speed OCT systems with wide field of view imaging applications comparable to OMAG based angiography reported by Choi et al [47] for a smaller field of view. The dense small capillaries of the iris which are typically less than 10 µm could not be well resolved by our low NA objective lens.…”