Background: The simultaneous recording of indocyanine green and fluorescein angiography is since more than twenty years possible. The real-time digital recording of angiograms is about since 10 years possible. Because of the poor temporal resolution due to technical limitations, both of the above methods were only seldom used routinely. Graphics workstations can digitize and store multiple video sources real-time with full video framerate. Comparing to conventional videoangiography, the quality can be improved significantly.
Materials and methods: Simultaneous ICG and Fluorescein (SIF) angiography images of a two-channel Scanning Laser Ophthalmoscope were digitized and stored real-time at a rate of 28-50 images/sec using a graphics workstation. The digitized image sequence could be replayed as a motion picture and/or single images of the recorded sequence could be analyzed separately.
Results: The simultaneous digital recording of angiograms is easier, than using two video tape recorders. It was possible to enhance the quality of the stored images using standard digital image processing procedures. Morphological measurements and densitometry were done with software developed for the UNIX workstation, or with personal computers using standard software packages.
Conclusion: Simultaneous digital ICG and fluorescein angiography has several advantages over conventional video-angiographies: the image quality is better, data retrieval is easier, it is easier to perform than conventional video angiography, image can be accessed through a computer network, it is easy to perform morphological and densitometrical measurements, etc.