A miniaturized catheter 2-D array for real-time, 3-D intracardiac echo cardiography

Abstract—The design, fabrication, and characterization of a 112 channel, 5 MHz, two-dimensional (2-D) array trans-ducer constructed on a six layer flexible polyimide inter-connect circuit is described. The transducer was mounted in a 7 Fr (2.33 mm outside diameter) catheter for use in real-time intracardiac volumetric imaging. Two transducers were constructed: one with a single silver epoxy matching layer and the other without a matching layer. The center frequency and 6 dB fractional bandwidth of the trans-ducer with a matching layer were 4.9 MHz and 31%, respec-tively. The 50 Ω pitch-catch insertion loss was 80 dB, and the typical interelement crosstalk was 30 dB. The final el-ement yield was greater than 97 % for both transducers. The transducers were used to acquire real-time, 3-D images in an in vivo sheep model. We present in vivo images of cardiac anatomy obtained from within the coronary sinus, includ-ing the left and right atria, aorta, coronary arteries, and pulmonary veins. We also present images showing the ma-nipulation of a separate electrophysiological catheter into the coronary sinus. I