An auto purge for an intravenous contrast injector of the type having a motorwhich advancesa plunger drive ram and configured for use with a pre-filled or user-filledsyringe containingan approximate known amount of air including a processor which causes themotor to moveand a memory storing a predetermined purge stop point representative of theapproximateknown amount of air in the syringe, the injector configured to automaticallyadvance theplunger drive ram an amount substantially equal to the predetermined purgestop pointrepresentative of the approximate known amount of air contained in thesyringe.
