The fluid injector system includes a source of injection fluid, a pump device, a fluid control device operably associated with the 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 top end, a bottom end and a raised projection, the raised projection being substantially rectangular in shape and extending longitudinally from the top end along the drip chamber body and terminating adjacent to the bottom end. A fluid level sensing mechanism is operably associated with the fluid control device, and includes a drip chamber support for supporting the drip chamber body and a fluid level sensor associated with the drip chamber support. The drip chamber support is adapted to support the drip chamber body such that the raised projection is in operational contact with the fluid level sensor and 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.