2D ring array transducers for real-time 3D imaging of atrial septal defect repair

We developed new miniature 2D array ring transducers integrated into interventional device catheters such as deploy atrial septal occluders. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter. We used a braided wiring technology from Tyco Electronics Corp to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz. We built another 55 element transducer with a single matching layer. The matching layer is from EBL Products, Inc. and is the #107 matching layer, .19 mm thick. The matching layer plate was metallized on both sides with 500 Å of nickel and 1000 Å of gold prior to bonding to the PZT layer with Epotek 301 Epoxy. The resulting average bandwidth was 60% centered at 4.4 MHz.