A pressure activated valve for a three-way connection between a catheter, an injector and a pressure transducer is disclosed. The valve includes a body that has an inlet for connection to an injector, an outlet for connection to a catheter and a secondary connection for connection to a pressure transducer. The body also includes a seal seat disposed between the secondary connection in both the inlet and the outlet. The body is flexibly connected to a plug seal. The plug seal is disposed between the seal seat in both the inlet and the outlet. The plug seal is movable between an open position spaced apart from the seal seat and biased towards the inlet and the outlet and a closed position against the seal seat thereby isolating the secondary connection from both the inlet and the outlet.