A liquid-transfer adapter operatively interposable between an injector and a vial is provided. The liquid-transfer adapter has an injector engaging portion configured for fluidly coupling to an injector and a vial coupling. The vial coupling includes a spike that has a spike axis and a tip portion configured for piercing a septum of a vial. The tip portion includes a plurality of facets that meet each other at one or more edges and at least one of the one or more edges is sloped with respect to the spike axis. The spike defines a channel extending therethrough in fluid communication with the injector engaging portion. A channel opening is defined in at least one of the facets and disposed without interrupting the edges.
