Initial results from a forward-viewing ring-annular ultrasound array for intravascular imaging

In this paper, we present some initial results from our proposed forward viewing ring-annular array for intravascular ultrasound imaging. We have investigated array design and image synthesis allowing simultaneous sideward imaging at 20 MHz and forward imaging at 10 MHz from the same array. This design is appropriate for over-the-wire delivery but limits the forward-looking aperture to a ring-annular array. In particular, a 1200 μm diameter ring-annular array with 64 elements has been constructed. The measured forward- viewing radiation pattern of an individual element indicates an acceptance angle range of over 90°. Currently, there are significant sensitivity and center frequency variations among the elements. Nevertheless, images of point targets are obtained as a proof-of-concept. Future improvements of the array will be discussed.