Name: Detecting Abnormalities in Choroidal Vasculature in a Mouse Model of Age-related Macular Degeneration by Time-course Indocyanine Green Angiography (Video) | JoVE Journal
Uploaded: 2014-02-19T15:00:00.000+00:00
Duration: 10 min 24 s
Description: Learn time-course Indocyanine Green Angiography to detect choroidal vascular abnormalities in mouse models of age-related macular degeneration. This method enables high-quality imaging comparable to human studies.

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5 minutes

This work was supported by NIH grant 1R01EY022901, the Career Development Award from Research to Prevent Blindness (RPB), C.M.Reeves &#38; M.A. Reeves Foundation, E. Matilda Ziegler Foundation for the Blind, Knights Templar Eye Foundation, and an unrestricted grant to the Department of Ophthalmology at the University of Utah from RPB. &#160;We thank Balamurali Ambati for technical assistance on the Spectralis Multi-Modality Imaging System and Tao Zhang for discussions and comments on the manuscript.

1. Preparation of Instruments
<ol>
	<li>The procedure is performed in a procedure room in an animal facility.</li>
	<li>Wear facemasks, hair bonnets, surgical gowns, sterile foot-covers, and gloves before beginning the experiment.</li>
	<li>Heat water in a beaker to ~40 &#176;C on a hotplate.</li>
	<li>Place a sterile blue pad on top of a heating pad that will be used later to maintain the mouse&#39;s body temperature during imaging. Turn on the heating pad.</li>
	<li>Prepare the Imaging System:
	<ol>
		<li>Remove the dust cover and turn on the laser.</li>
		<li>Take out the 55&#176; lens and mount it onto the machine.</li>
		<li>Open the imaging software from the computer and input the information of the mouse for imaging under a new patient&#39;s sheet (e.g. genotype, age, etc.). Under &#34;device type&#34;, choose Infrared (IR) mode.</li>
	</ol>
	</li>
</ol>
Note: It has been reported that the use of an external double aspheric lens can improve the image quality17-20 although we have no problem in obtaining high quality images by IV-ICGA without using external lenses (see representative results, Figures 1-4).
2. Tail Vein Injection of ICGA
<ol>
	<li>Dilate mouse eyes with 1% Tropicamide ophthalmic solution and wait 5 min.</li>
	<li>Weigh the mouse to determine the amount of anesthesia (Ketamine/Xylazine/Acepromazine 65-100/10-20/1-3 mg/kg) needed.</li>
	<li>Retrieve a sterile 1-ml&#160;syringe along with a 32&#160;G&#160;needle. Inject the mouse intraperitoneally with the anesthetics (13 mg/ml&#160;Ketamine, 2.6 mg/ml Xylazine, 0.3 mg/ml&#160;Acepromazine in sterile PBS). Wait until the mouse is fully anesthetized (~5 min).</li>
	<li>Place the mouse tail into 40 &#176;C warm water to cause vasodilatation of the vein.</li>
	<li>Retrieve a 1&#160;ml&#160;syringe with a 32&#160;G&#160;needle. Withdraw the desired amount of ICG, typically 50 &#956;l&#160;of 1 mg/ml&#160;ICG, which is sterile filtered with a 0.2 &#181;M syringe filter into a sterile tube,&#160;for a 25 g mouse (2 mg/kg). Be careful not to introduce any air into the syringe.</li>
	<li>Wipe the tail with an alcohol swab to sterilize the area to be injected.</li>
	<li>Hold the tail with one hand so that the lateral tail vein is upward. With the bevel of the needle facing upward, inject the needle ~2 mm into the vein at a minimal angle. Be careful not to perforate the vein. Draw back on the syringe slightly and look for traces of blood flow into the needle hub, which indicates that the needle was successfully inserted into the vein.</li>
	<li>Slowly inject ICG into the vein. There should be minimal resistance when injecting. Remove the needle and apply an alcohol swab directly to the injection site for ~5-10 sec&#160;to stop any bleeding. The mouse is then ready for imaging. In order to catch the early phase (0-4 min after injection), it is essential to image the mouse quickly.</li>
</ol>
Note: Mouse eyes can easily get dry and can develop cataract under anesthesia. It is important to keep the eye moist by applying sterile PBS during the procedure. Wipe off excess PBS with a sterile cotton swab before ICGA recording. Other labs have used a contact lens to avoid dehydration of the cornea17-20.
3. ICG Angiography
<ol>
	<li>Start to take images 30-40 sec&#160;after ICG injection, which permits the capture of the early phase of choroidal filling until retinal and choroidal circulations are at maximum brightness (0-4 min). The retinal vasculature is best visualized at focus ~35-45 diopters and choroidal vasculature is visualized at 10-15 diopters. 
	 
	Note: During the first examination of an animal model, it is recommended to capture images from all angles (nasal, temporal, dorsal and ventral) to identify all possible abnormalities in the vasculature. During the early phase, both medium and large choroidal arteries and veins are well visualized. In the animal model used in this protocol, choroidal lesions (e.g. polypoidal dilations) may start to appear 1 min into the early phase.</li>
	<li>Set the image focus on the vasculature. Control for brightness and focus using the control module and focus knob, respectively. These values are adjustable digitally and are easily kept constant. Keep the distance from the mouse eye to the camera lens constant to ensure image quality is reproducible using the technique that follows. 
	 
	Note: Since the device can only image a portion of the posterior eye, we try to keep the focus, brightness, and the distance between the camera lens and the mouse eye constant as we image the entire posterior eye from different angles. The key to this is to align the circle-shaped luminescence emitted by the ICG through the eye with the field of view of the camera. This is accomplished by making left-to-right, up-and-down, and in-and-out adjustments of the camera position until the entire image has no dark areas. When the luminescence and the field of view of the camera are lined up, the distance from the eye to the lens will be reproducible for the next set of images as well as at an optimal distance for quality imaging.</li>
	<li>Once the vasculature is in focus, capture the image frames by pressing the round black button on the acquisition module. The round black button can also be used to reduce or enhance the signal of ICG for best image quality.</li>
	<li>Determine the optimal view angle and focusing depth to image choroidal lesions. It is important to keep the position of the eye, the focusing depth, and other device settings fixed for the entire time-course ICGA. The images are saved by pressing acquire button on the touch screen panel of the acquisition module.</li>
	<li>Acquire images in the middle phase at 6-15 min after injection. 
	 
	Note: Both the choroidal and retinal vessels become less distinct. Choroidal vasculature appears as diffuse fluorescence. Choroidal lesions exhibiting hyperfluorescence emerge in contrast to the fading surrounding normal background fluorescence.</li>
	<li>Acquire images in the late phase at 17-25 min after injection. 
	 
	Note: Hyperfluorescence fades. Both choroidal and retinal vessels are no longer visible. The optic nerve head becomes black. Hyperfluorescent choroidal lesions have maximal contrast with the fading background.</li>
	<li>After finishing the acquisition of images, apply a clear lubricant eye gel to mouse eyes and leave the mouse on a heating pad for recovery.</li>
	<li>Return mice to their cages and holding area. Export images as Tiff or JPEG files for further analysis.</li>
</ol>
Note: The timing of each phase is not absolute. We found that the timing of each phase might change depending on the amount of ICG injected. More ICG tends to prolong each phase. The best way to define a phase is according to the key features of each phase listed above.

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<li>Jones, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Increased+expression+of+multifunctional+serine+protease%2C+HTRA1%2C+in+retinal+pigment+epithelium+induces+polypoidal+choroidal+vasculopathy+in+mice%5BTitle%5D)+AND+%22Proc.+Natl.+Acad.+Sci.+U.S.A%22%5BJournal%5D)">Increased expression of multifunctional serine protease, HTRA1, in retinal pigment epithelium induces polypoidal choroidal vasculopathy in mice.</a> Proc. Natl. Acad. Sci. U.S.A. 108, 14578-14583 (2011).</li>
<li>Alex, A. F., Heiduschka, P., Eter, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Retinal+fundus+imaging+in+mouse+models+of+retinal+diseases%5BTitle%5D)+AND+%22Methods+Mol.+Biol%22%5BJournal%5D)">Retinal fundus imaging in mouse models of retinal diseases.</a> Methods Mol. Biol. 935, 41-67 (2013).</li>
<li>Seeliger, M. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((In+vivo+confocal+imaging+of+the+retina+in+animal+models+using+scanning+laser+ophthalmoscopy%5BTitle%5D)+AND+%22Vision+Res%22%5BJournal%5D)">In vivo confocal imaging of the retina in animal models using scanning laser ophthalmoscopy.</a> Vision Res. 45, 3512-3519 (2005).</li>
<li>Fischer, M. D., Zhour, A., Kernstock, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Phenotyping+of+mouse+models+with+OCT%5BTitle%5D)+AND+%22Methods+Mol.+Biol%22%5BJournal%5D)">Phenotyping of mouse models with OCT.</a> Methods Mol. Biol. 935, 79-85 (2013).</li>
<li>Jian, Y., Zawadzki, R. J., Sarunic, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Adaptive+optics+optical+coherence+tomography+for+in+vivo+mouse+retinal+imaging%5BTitle%5D)+AND+%22J.+Biomed.+Opt%22%5BJournal%5D)">Adaptive optics optical coherence tomography for in vivo mouse retinal imaging.</a> J. Biomed. Opt. 18, 56007 (2013).</li>
<li>Ciardella, A. P., Donsoff, I. M., Huang, S. J., Costa, D. L., Yannuzzi, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polypoidal+choroidal+vasculopathy%5BTitle%5D)+AND+%22Surv.+Ophthalmol%22%5BJournal%5D)">Polypoidal choroidal vasculopathy.</a> Surv. Ophthalmol. 49, 25-37 (2004).</li>
<li>Sasahara, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polypoidal+choroidal+vasculopathy+with+choroidal+vascular+hyperpermeability%5BTitle%5D)+AND+%22Am.+J.+Ophthalmol%22%5BJournal%5D)">Polypoidal choroidal vasculopathy with choroidal vascular hyperpermeability.</a> Am. J. Ophthalmol. 142, 601-607 (2006).</li>
<li>Silva, R. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polypoidal+choroidal+vasculopathy+and+photodynamic+therapy+with+verteporfin%5BTitle%5D)+AND+%22Graefes+Arch.+Clin.+Exp.+Ophthalmol%22%5BJournal%5D)">Polypoidal choroidal vasculopathy and photodynamic therapy with verteporfin.</a> Graefes Arch. Clin. Exp. Ophthalmol. 243, 973-979 (2005).</li>
<li>Yannuzzi, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Polypoidal+choroidal+vasculopathy+masquerading+as+central+serous+chorioretinopathy%5BTitle%5D)+AND+%22Ophthalmology%22%5BJournal%5D)">Polypoidal choroidal vasculopathy masquerading as central serous chorioretinopathy.</a> Ophthalmology. 107, 767-777 (2000).</li>
<li>Janssen, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Abnormal+vessel+formation+in+the+choroid+of+mice+lacking+tissue+inhibitor+of+metalloprotease-3%5BTitle%5D)+AND+%22Invest.+Ophthalmol.+Vis.+Sci%22%5BJournal%5D)">Abnormal vessel formation in the choroid of mice lacking tissue inhibitor of metalloprotease-3.</a> Invest. Ophthalmol. Vis. Sci. 49, 2812-2822 (2008).</li>
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<li>Grossniklaus, H. E., Kang, S. J., Berglin, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+choroidal+and+retinal+neovascularization%5BTitle%5D)+AND+%22Prog.+Retin.+Eye+Res%22%5BJournal%5D)">Animal models of choroidal and retinal neovascularization.</a> Prog. Retin. Eye Res. 29, 500-519 (2010).</li>
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</ol>

YF is an inventor of two pending patents that are relevant to the AMD mouse model used in this work.&#160;SK, ZB, and ADJ have nothing to disclose.

In this study, we demonstrated the use of ICGA to image choroidal lesions in HTRA1 transgenic mice. The characteristics of the early, middle, and late phases of ICGA in our mouse model match the time course well in human studies1. This is important to make better comparisons between human pathology and animal phenotypes, which are invaluable for research on pathophysiological mechanisms and treatment strategies of conditions related to the choroid such as AMD.
We first performed ICG...

Indocyanine green angiography (ICGA) is a diagnostic test to image problems related to blood vessels in the eye. The absorption spectrum of ICG ranges from 790-805 nm while the emission spectrum ranges from 770-880 nm with the peak emission at 835 nm&#160;1. This is different from the other popular dye, sodium fluorescein, whose spectrum falls in the visible range. The infrared spectrum enables ICG to penetrate through retinal pigment epithelium (RPE), serosanguineous fluid, and lipid exudates, all of which can easily block visualization by sodium-fluorescein based fluorescein angiography (FA). ICG is 98% protein-bound in the vasculature resulting in less extravasation, allowing enhanced imaging of choroidal vessels and choroidal lesions1,2. ICGA is almost the only choice to visualize choroidal vasculature, which is posterior to RPE. Figure 1 shows the comparison of ICGA and FA in imaging vasculature in mouse eyes. FA can be used to image the retinal vasculature well but not the choroidal vasculature. In contrast, ICGA can be used to image both retinal and choroidal vasculature. ICGA is performed with high-resolution digital imaging systems or scanning laser ophthalmoscopes (SLO) together with infrared-sensitive video cameras, which we will use in this study.
In the clinic, ICGA has been recommended in diagnosing a number of chorioretinal disorders involving the choroidal vasculature including Polypoidal Choroidal Vasculopathy (PCV), Retinal Angiomatous Proliferation (RAP), angioid streaks, vitelliform macular dystrophy, central serous chorioretinopathy, choroidal hemangioma, hemorrhaging retinal arteriolar macroaneurysms, choroidal tumors, and certain forms of posterior uveitis1,3. The combination of ICGA with FA and Optical Coherence Tomography (OCT) provide powerful tools for the clinicians in the diagnosis and management of exudative age-related macular degeneration (AMD)4-10. ICGA is especially useful for diagnosing conditions involving the choroid. In fact, ICGA is considered the gold standard for diagnosing PCV, a variant of exudative AMD11-13. PCV is characterized by a network of branching vessels with terminal polypoidal dilations in the choroidal vasculature11-13. PCV is frequently associated with recurrent serosanguineous detachments of the RPE and retina with leakage and bleeding from the polypoidal components11,14,15. We recently reported the generation of the first PCV animal model by transgenically expressing human HTRA1, a multi-functional serine protease, in mouse retinal pigment epithelium (RPE)16. We showed that increased HTRA1 induced characteristic features of PCV, e.g. polypoidal lesions.
Here we demonstrated the use of time-course ICGA by tail vein injection in AMD research using our HTRA1 mouse model. Our data suggest that IV-ICGA is superior to IP (or subcutaneous (SC))-ICGA that are currently used in the field17,18 for characterizing lesions in the choroid.
Statement on Animal Research&#160;
Animal experiments were conducted according to protocols approved by Institutional Animal Care and Use Committee (IACUC), and were performed in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research.

<table><tbody><tr><td>Spectralis Multi-Modality Imaging System</td><td>Heidelberg Engineering, Germany</td><td>SPECTRALIS HRA+OCT</td><td></td></tr><tr><td>Tropicamide ophthalmic solution (1%)</td><td>Bausch &amp;amp; Lomb</td><td>NDC 24208-585-64</td><td>for dilation of pupils</td></tr><tr><td>GenTeal Gel</td><td>Genteal</td><td>NDC 58768-791-15</td><td>&amp;nbsp;clear lubricant eye gel&amp;nbsp;</td></tr><tr><td>Ketamine</td><td>Vedco Inc</td><td>NDC 50989-996-06</td><td></td></tr><tr><td>Xylazine</td><td>Lloyd Laboratories</td><td>NADA 139-236</td><td></td></tr><tr><td>Acepromazine</td><td>Vedco Inc</td><td>NDC 50989-160-11</td><td></td></tr><tr><td>32-G Needle</td><td>Steriject</td><td>PRE-32013</td><td></td></tr><tr><td>1-ml syringe</td><td>BD</td><td>309659</td><td></td></tr><tr><td>Indocyanine Green</td><td>Pfaltz &amp;amp; Bauer</td><td>I01250</td><td></td></tr></tbody></table>

detecting abnormalities in choroidal vasculature in a mouse model of age-related macular degeneration by time-course indocyanine green angiography

Detecting Abnormalities in Choroidal Vasculature in a Mouse Model of Age-related Macular Degeneration by Time-course Indocyanine Green Angiography

Indocyanine Green&#160;Angiography (or ICGA) is a technique performed by ophthalmologists to diagnose abnormalities of the choroidal and retinal vasculature of various eye diseases such as age-related macular degeneration (AMD). ICGA is especially useful to image the posterior choroidal vasculature of the eye due to its capability of penetrating through the pigmented layer with its infrared spectrum. ICGA time course can be divided into early, middle, and late phases. The three phases provide valuable information on the pathology of eye problems. Although time-course ICGA by intravenous (IV) injection is widely used in the clinic for the diagnosis and management of choroid problems, ICGA by intraperitoneal injection (IP) is commonly used in animal research. Here we demonstrated the technique to obtain high-resolution ICGA time-course images in mice by tail-vein injection and confocal scanning laser ophthalmoscopy. We used this technique to image the choroidal lesions in a mouse model of age-related macular degeneration. Although it is much easier to introduce ICG to the mouse vasculature by IP, our data indicate that it is difficult to obtain reproducible ICGA time course images by IP-ICGA. In contrast, ICGA via tail vein injection provides high quality ICGA time-course images comparable to human studies. In addition, we showed that ICGA performed on albino mice gives clearer pictures of choroidal vessels than that performed on pigmented mice. We suggest that time-course IV-ICGA should become a standard practice in AMD research based on animal models.

We performed ICGA time course in HTRA1 transgenic mice and control WT littermates, both of which are on the CD1 background. The albino CD1 background was selected to facilitate indocyanine green angiography (ICGA) imaging (see DISCUSSION). Some aneurism like dilations began to appear in the early phase in the HTRA1 mouse (Figure 2, a red arrow indicates the dilation at the tip of a vessel and a red circle indicates a cluster type polypoidal lesion). Choroidal vessels are clearly visible in both WT and HT...

Indocyanine Green Angiography (or ICGA) performed by tail vein injection provides high quality ICGA time course images to characterize abnormalities in mouse choroid.

Indocyanine Green&#160;Angiography (or ICGA) is a technique performed by ophthalmologists to diagnose abnormalities of the choroidal and retinal ...

The overall goal of this procedure is to detect abnormalities in the choroidal vasculature in mouse models of age-related macular degeneration using time course endo in green and geography. This is accomplished by first preparing the animals and die for injection. The second step is to perform tail vein injections of incy in green.Next images of the eye are acquired in the early middle and late phases of incy in green angiography, which are then exported and analyzed. Ultimately, time course incy in green angiography may be used as a standard procedure for characterizing various types of lesions in the choroid of age-related macular degeneration. Mouse models.The main advantage of this technique, our existing methods, like intraperitoneal injection of endo signin green, is that it provides high quality time course images that are comparable to human studies To begin the procedure, dress in the proper attire for working with animals. This includes putting on surgical gowns, sterile foot covers, hair, bonnets, face masks, and gloves. Then prepare the heating pad to be used during imaging by turning on the system, setting the temperature to 37 degrees Celsius and covering it with a sterile blue pad.Next, turn on a hot plate and heat a beaker of water to 40 degrees Celsius. Prepare the imaging system prior to the tail vein injection by pre warming the laser and mounting a 55 degree lens onto the machine. Then open the imaging software and input the identifying information of the mouse for imaging under a new patient sheet.Under device type, choose infrared mode. With the imaging system set up, dilate the mouse's eyes with a 1%tropic IDE ophthalmic solution, and wait five minutes. During this time, weigh the mouse to determine the amount of anesthesia that is required.Then inject a mixture of ketamine, xylazine, and acepromazine intraperitoneal as described in the accompanying text protocol. And wait about five minutes until the mouse is fully anesthetized. Instead of covering the eyes of the anesthetized mouse with eye ointment, apply sterile PBS to the eyes every two minutes or insert specialized contact lenses to prevent them from drying out and developing cataracts.Once anesthetized, place the tail of the mouse into 40 degrees Celsius water for 20 to 30 seconds in order to dilate the tail vein. Then use a one milliliter syringe equipped with a 32 gauge needle to draw up two microliters per gram of body weight of a one milligram per milliliter indocyanine green solution. Be careful not to introduce any air bubbles into the syringe.Next, hold the tail with one hand so that the lateral tail vein is upward and wipe the tail with an alcohol swab to sterilize the area to be injected. Then inject the needle about two millimeters into the vein at a minimal angle with the bevel of the needle facing upward. Draw back on the syringe slightly and look for traces of blood flow into the needle hub, indicating that the needle was successfully inserted into the vein.Then slowly inject the indocyanine green solution. There should be minimal resistance when injecting following injection. Remove the needle and apply an alcohol swab directly to the injection site for five to 10 seconds to stop any bleeding.The mouse is then ready for imaging following tail vein injection. Quickly transfer the mouse to the previously prepared imaging system to take images during the early phase of the choroidal filling. First, set the image, focus on the vasculature of interest.Focus between 35 and 45 diopters for the retinal vasculature and between 10 and 15 diopters for the choroidal vasculature. Then control for brightness using the control module, adjust the values for focus and brightness digitally, and once set, keep them constant for that type of shot. Also, keep the distance from the mouse eye to the camera constant.To ensure reproducible image quality. Perform the initial screening by imaging the entire posterior of the eye from different angles. Start by aligning the circle shaped luminescence emitted by the indocyanine green dye with the camera's field of view.To accomplish this, make left to right, up and down and in and out. Adjustments of the camera position until the entire image is in focus and has no dark areas. Record the optimal device settings for repeat procedures.Once the vasculature is in focus, capture the image frames by pressing the round black button on the acquisition module. This button can also be used to reduce or enhance the signal of indoc and green for best image quality. To examine a particular lesion area based on the previous screening results, set up the imaging system using the optimal angle and device settings previously determined.Keep the position of the eye view angle, focusing depth and other device settings fixed for the entire time.Course. Save the images by pressing the acquire button on the touchscreen panel of the acquisition module. Continue to acquire images in the early phase until retinal and choroidal circulations are at maximum brightness.This can take up to four minutes. Then continue to acquire images in the middle phase at six to 15 minutes post-injection. As can be seen here, the choroidal vessels become less distinct in this phase and appear as diffuse fluorescence.Additionally, choroidal lesions exhibiting hyperfluorescence emerge next acquire images in the late phase at 17 to 25 minutes post injection. During this phase, the hyperfluorescence fades and vessels are no longer visible. Also, the optic nerve head becomes black and the choroidal lesions have maximal contrast with the fading background.After finishing the acquisition of images, apply a clear lubricant IGEL to the mouse eyes and leave the mouse on a heating pad for recovery. Once they have regained some movement, return mice to their cages and holding area. Finally, export all the images as image files or video files for further analysis.Shown here is a comparison of sodium fluorescein based fluorescein angiography and endocyt in green angiography in imaging, mouse retinal and choroidal vasculature. While retinal vessels can be seen using both FA and ICGA, choroidal vessels can only be seen with ICGA. Here are images taken of the choroidal vasculature following tail vein injection of endo in green in the wild type mouse.No dilations or lesions were found at any of the imaging stages in the HT A one transgenic mouse. However, both dilations and cluster type polypoidal lesions were found in the early stage, and several more lesions appeared in the middle phase and became clearer in the late stage to compare between tail vein and intraperitoneal injection of the indocyanine green on imaging quality to additional HRA one transgenic mice were imaged following IP injection. The choroidal vasculature is mostly invisible five minutes after injection for both mice and is invisible more than 12 minutes for the mouse.In the lower panels, in addition to the root of injection pigment color also influences the quality of images. Here a pigmented and albino mouse were compared using time course IV incy in green, an geography. The albino mouse had much sharper images of both big and small choroidal vessels at the early and middle phases and would provide a good breeding background for further studies in this area After its development.This technique paved the way for researchers in the field of vision research to explore choroid abnormalities in mouse models.

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Detecting Abnormalities in Choroidal Vasculature in a Mouse Model of Age-related Macular Degeneration by Time-course Indocyanine Green Angiography (Video) | JoVE Journal

Detecting Abnormalities in Choroidal Vasculature in a Mouse Model of Age-related Macular Degeneration by Time-course Indocyanine Green Angiography

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