Abstract: The present invention relates to an ultrasonic imaging catheter having an open proximal end and a closed distal end. The closed distal end contains a septum and a situs for targeting the septum. A fluid filled syringe may be insertable though the situs and the septum to fill a chamber defined by the catheter sheath and the septum, with ultrasonic transmission fluid. The chamber subsequently receives an ultrasonic image generator and receiver within the fluid filled chamber. Injection of fluid through the septum eliminates the likelihood of air bubbles forming within the chamber which otherwise damages the ultrasonic images generated thereby when that chamber is filled with fluid through the proximal end of the catheter sheath.