Abstract: An ultrasound transducer array probe for intraluminal ultrasound imaging is situated on a distal end of a catheter. The probe has a flex circuit that accepts terminations from a plurality of coaxial cables admitted through the catheter, and electrically conveys these signals to integrated circuits and an ultrasound array acoustic stack, preferably having seventy-two elements. The circuit has more than one layer of metal tracings to support complicated electrical interconnections. The acoustic stack preferably includes two quarter-wave matching layers and an acoustic backing layer composed of urethane, AIN.sub.3, tungsten trioxide, and micro-balloons. The flex circuit can be formed of two sections that are joined during manufacture.