A dual port syringe has an upper port for connection to a fluid reservoir and
a
lower port for delivery of the medical fluid under pressure to a patient. A first
valve is connected between the fluid reservoir and the upper port, and second valve
is connected between the lower port and the patient. During a fill operation, a
piston is moved within the syringe to drawn fluid from the reservoir into the syringe
through the upper port. During injection operation, the piston moves in an opposite
direction to force fluid out of the syringe through the lower port.