Automatic measurement of dye filling of simultaneous digital ICG and Fluorescein angiography sequences

Background: The ICG filling is supposed to be faster than Fluorescein filli ng. Interestingly the filling characteristics of these dyes were never corr elated directly using precise quantitative methods. Since ICG and Fluoresce in are injected as a mixture, the simultaneous 2-channel angiography provid es a suitable method to correlate the filling characteristics of the dyes. Material and Methods: The simultaneous ICG and Fluorescein angiograms were recorded with a Rodenstock Scanning Laser Ophthalmoscope. The angiographic images were digitized realtime with a graphic workstation. Filling characte ristics of the two dyes was calculated after off-line eye tracking in diffe rent regions of interests (ROIs) on the central retina. Results: The Fluorescein filling was faster than the ICC filling in 56.5% o f our patients. In 26% of our patients was a mixed filling detectable. Depe nding on the position of the ROIs the Fluorescein or ICC filling was faster . In only 17.5% of our cases was the ICG filling faster than the Fluorescei n filling. Conclusion: Our results show that Fluorescein filling in more than 50% of t he cases is faster than ICG filling and only a minority of the patients has a faster ICC; filling. According to our experience the filling pattern of the two dyes is individual, there is no rule of thumb for the filling.