Abstract
Abstract: :
Purpose: To image and enhance spatial resolution of choroidal neovascularization (CNV) in the rat model. Methods: CNV was induced in one eye each of 12 pigmented rats by delivery of 10 laser pulse exposures to each eye, for a total of 120 exposures. The laser pulses were delivered at a distance from the retina of approximately twice the diameter of the optic disc. The laser parameters were as follows: 810 nm wavelength, 120 mW exposure power, 100 ms exposure time, 75 µm spot size. Angiograms using SLO in combination with different doses of sodium fluorscein (7, 14, and 21mg/kg) and different doses of indocyanine green ( 0.5, 1, and 1.5 mg/kg) were performed immediately after, and 3, 7, 14, and 30 days after laser exposure. Results: In 85% of the 120 laser exposures, CNV was evident 14 days following the laser exposure. This Bruch's-membrane-rupture CNV model was confirmed with both sodium fluorescein and indocyanine green angiograms. Imaging capability and visibility were similar with all concentrations of sodium fluorescein, whereas the 1.5 mg/kg concentration of indocyanine green produced the best imaging, compared with the lower concentrations. Additionally, the imaging capability with indocyanine green was generally superior to that obtained with sodium fluorescein. Conclusion: CNV created with a longer wavelength (810 nm) appears to be more efficient than CNV created by using a krypton laser (red wavelength), as was done in earlier studies (85% vs. 30%). The increased efficiency produced by the IR laser could be a result of deeper penetration into the tissue. The detailed structure of the CNV and the high resolution of this vascular network obtained using a high dose of indocyanine green (1.5 mg/kg, which is approximately 3 to 4 times the routine human dose) suggests that visibility in human subjects might benefit from higher doses as well.
Keywords: 346 choroid: neovascularization • 483 neovascularization • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)