The Basis on the Interpretation of Indocyanine Green Fundus Angiography.

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07671932
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Ophthalmology
• Research Institution: Saitama Medical School
• Principal Investigator: YONEYA Shin Saitama Medical School, Department of Ophthalmology, Professor, 医学部, 教授 (40143234)
• Co-Investigator(Kenkyū-buntansha): MORI Keisuke Saitama Medical School, Department of Ophthalmology, Assistant Professor, 医学部, 講師 (90251090) ; OKI Ryutaro Saitama Medical School, Department of Ophthalmology, Assistant Professor, 医学部, 講師 (00194093)
• Project Period (FY): 1995 – 1996
• Keywords: インドシアニングリーン / 蛍光眼底造影 / 血清蛋白 / 硝子体フルオロフェトメータ

Research Abstract

It is known that indocyanine green angiography demonstrates lower permeability than fluorescein angiography in varied pathological blood retinal varrier. Ohterwiase, there studied little basis on the interpretation of indocyanine green angiography, epecially on vascular permeability.
We investigated the dye permeability with indocyanine green and other fluorescein compounds in experimental model of laser photocoagulation, choroidal neovascularization and retinal angitis. Angiorgaphic and histopathological evaluation revealed that inmature and active choroidal neovascularizations showed intensive vascular permeability. This finding indicates that indocyanine green angiography may delineate the activity of choroidal neovascularization clinically. In addition, fluorescent dyes of large molecules (above 40000 MW) did not permeate through outer blood retinal barrier breakdown induced by laser photocoagulation, while even fluorescent dyes of very large molecules (above 150000 MW) permeated th rough inner blood retinal barrier breakdown with retinal angitis. In contrast, indocyanine green angiography demonstrated little permeability in both experimental model. Therefore, binding property of indocyanine green with serum proteins might be an importamt factor in interpretation of the angiography.
Therefore, we investigated the binding property of indocyanine green with serum protein by biochemical modality, and found that indocyanine green dyes bind especially with serum lipoprotein (above 400000 MW). This basic datum may indicate that indocyanine green angiography demonstrates the biodistribuition of lipoprotein in the fundus.
Based on these pathological and biochemical investigations, we performed indocyanine angiography at our clinic. Firstly, choroidal dye permeability was analyzed quantitatively with the image analysis program of IMAGEnet. With this analysis, multiple posterior pigment epitheliopathy demonstrated sgnificant higher choroidal fluorescnece than age-matched normals. This facts proposed that pathogenesis of multiple posterior pigment epitheliopathy may be the choroidal hyperpermeability. In cases of age-related macular degeneration, we could speculate the abnormal lipid deposition in Bruch's membrane. As cited above, the interpretation of indocyanine green angiography based on pathological and biophysiological aspects may lead us to determine original pathogenesis of various retinochoroidal diseases.