1. A catheter apparatus, comprising: an elongated body having a longitudinal axis; an ultrasonic transducer array mounted on the body, the array being operated for transmitting ultrasonic signals for imaging; a control circuitry operatively connected to the ultrasonic transducer array, the control circuitry being external of the elongated body; and wherein the ultrasonic transducer array is an offset stereoscopic imaging ultrasound transducer array.