Synthetic phased array imaging of coronary arteries with an intraluminal array

Previous synthetic array methods for intraluminal imaging of coronary arteries have been greatly extended. First, a 64 element, high efficiency, ceramic piezoelectric, array transducer operating at 20 MHz has been constructed. The array is mounted on the surface of a 1.2 mm diameter catheter appropriate for coronary artery applications. Second, integrated into the catheter tip is a custom analog chip set permitting complete data capture from the array. That is, on each firing any combination of array elements can be selected independently as transmitter or receiver. Using data acquired in this way, a complete phased array aperture (i.e. independent transmit and receive apertures) can be reconstructed. To create real-time images, a beam former based on a custom application specific integrated circuit (ASIC) has been designed and built. Beam forming coefficients were derived using an optimal filtering approach accounting for the circular geometry of the array