gms | German Medical Science

With the advent of confocal scanning laser ophthalmoscopy (cSLO) more sensitive tools are available for routine fluorescence angiography compared to conventional fundus cameras. We determined the minimal required amounts of fluorescein and indocyanine green (ICG) dye for fluorescence angiography.

Fluorescein and ICG angiography was performed in 35 patients with various retinal pathologies using a novel cSLO (Heidelberg Retina Angiograph 2, Heidelberg Engineering). The amount of fluorescein (500 mg, 250 mg, 200 mg, 166 mg) and ICG (15 mg, 10 mg, 5 mg, 2.5 mg) bolus injections was gradually tapered. Standardized acqusition of images was performed at 5, 15 and 30 min after injection. Early phase images were recorded as a series of images (16 frames/sec). For quasi-simultaneous angiography ICG was injected 2 min after fluorescein to optimize adjustments and, therefore, image quality during the early phase. Assessment of possible lens opacities was performed using a Scheimpflug camera (EAS-1000, Fa. Nidek).

At amounts as low as 166 mg fluorescein in 1.6 ml sufficient image quality was achieved at all phases after injection. Only late phase images (30 min) showed somewhat less contrast which was, however, not relevant for interpretation and clinical management. For ICG angiography the lowest amount of injected dye to allow sufficient image quality was 2.5 mg in 0.5 ml.

Using novel confocal scanning laser systems for routine angiography amounts of injected fluorescence dye can be reduced by a third for fluorescein (166 mg) and by a sixth for ICG (2.5 mg) without relevant loss of image quality or information. This allows for potential savings especially in 'high-volume' angiographic/retinologic centers.