[Standardized fluorescein injection in serial angiography (author's transl)].

Maximal initial dye concentration in the retinal arteries is desirable for high quality fluorescein Angiograms and is essential for circulation studies. Such high initial dye concentrations can only be achieved by a very rapid fluorescein injection technique necessitating an automatic injector. A reliable easy to use "spring-injector" has been designed for clinical use (Figs. 1 and 2). A disposable syringe is driven by a spring contained in a metal cylinder. Microswitches are activated by the piston of the injector triggering one exposure each at the beginning and at the end of the injection. Time and duration of the injection are therby permanently documented on the film. The "Terumo Disposable Syringe 10 cc" is used routinely. By interposing a plastic connector between syringe and injector-piston the injection-volume can be reduced to 5 ml. With diffferent connectors one can inject an volume desired up to 10 ml. The duration of the injection can be varied by using different intravenous catheters. Routinely the "VYGON Trocaflex catheter Nr. 125.16" with a needle diameter of 1.1 mm and a length of 30 cm is used resulting in an injection time of 10 ml/1.0 sec or 5 ml/0.5 sec. The largest Trocaflex catheter (No. 125.20) will shorten the injection time to 10 ml/0.5 sec and 5 ml/0.25 sec respectively. Even faster injections can be achieved by shortening the catheter or by using a stronger spring. With the described injector, high-speed, well-standardized fluorescein injections are possible. The intravenous catheter makes parvenous injections impossible and will allow for repeated angiograms even on different days without the need for a new venous puncture.