The fluid injector system includes a source of injection fluid, a pump device, and a fluid path set in fluid connection with the source of injection fluid and the pump device. The fluid path set includes a drip chamber including an elongated body having a raised projection from substantially a top end to substantially a bottom end, the elongated body configured to receive and contain the injection fluid. A fluid level sensing mechanism is operably associated with a fluid control device, and includes a support for the drip chamber body, wherein the support is adapted such that the raised projection is in operational contact with a fluid level sensor associated with the support. The fluid level sensing mechanism is operable to transmit ultrasonic or light energy through the raised projection to be sensed by the fluid level sensor for sensing the injection fluid level in the drip chamber.