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UM Schmidt-Erfurth, W Ahlswede, S Michels, R Birngruber, H Laqua; Three-dimensional Analysis of Photodynamic Therapy (PDT)-induced Vascular Effects in Choroidal Neovascularization (CNV) and Choroid: A Two Year Follow-up . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3978.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To document structural vascular changes in CNV and surrounding choroid during two years of follow-up in a randomized trial of a retreatment regimen with PDT compared to a control group. Methods: A prospective, double-masked study, the TAP investigation, included 60 patients with subfoveal CNV. PDT with verteporfin (Visudyne) was applied at baseline and in 3 month intervals whenever leakage was detected by fluorescein angiography (FA). The recommended standard procedure with a light dose of 50 J/cm2 was administered. As part of an approved ancillary study confocal indocyanine green angiography (ICGA) was undertaken regularly at baseline and at each interval for up to two years. Sets of 32 image series were analyzed topographically and the vascular surface of CNV and choriocapillaries was reconstructed in a three-dimensional display. Lesions were evaluated in respect to the detection rate and size in 2D-versus 3D-ICGA (in %), the level of prominence (in grade +1, +2, +3) or the presence of a choroidal defect in the treatment (n=40) and the control (n=20) group. Results: The CNV pathology was missed by conventional 2D-ICGA in 25%, but was present in all 3D-ICGA. CNV was found to be larger in 3D-versus 2D-ICGA in 65%. At baseline, each CNV lesion was delineated by 3D-ICGA as well-defined vascular prominence (mean grade + 1.4) in the PDT as well as the control group. PDT-treated lesions were reduced in prominence by month 6 (grade + 0.8) and flattened to the level of the physiological choroid at month 12 (grade +0.3). CNV prominence was replaced by a persistent vascular defect in the choroidal surface in 50% of treated eyes beyond 12 months. The CNV prominence in the control group remained essentially unchanged over time (mean grade +1.1 at 24m). The initial lesion diameter (2.8 DA) continuously decreased most intensively during the first 12 months (1.9 DA) and less until month 24 (1.7 mean DA) in the PDT group. Control lesions progressively enlarged from 2.4 DA at baseline to 3.5 DA at month 6 and remained stable until month 24 with a mean of 3.6 DA. Conclusion: 3D-ICGA may be a reliable method to detect CNV, quantify the dimension and identify the active growth phase of the lesion. In PDT with verteporfin 3D-ICGA visualizes characteristic changes with persistent choroidal perfusion defects associated with additive treatments during long-term follow-up.
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