Current intra-arterial ultrasound imaging systems and automatic contour detection

Three techniques for the intra-arterial ultrasonic visualization of the lumen cross section are described. These are based on: 1) single rotating transducer; 2) single fixed transducer with rotating mirror; and 3) fixed transducers in a multiple phased array. In vivo tests have shown that the single transducer currently produces the clearest images at the cost of a complex mechanical rotational design. The multiple phased array requires further development to realize its full potential. These catheter tip transducers are finding application in desobstruction techniques such as laser ablation and spark erosion, where it is important to precisely guide the catheter and avoid arterial perforation. Finally, a method for quantifying the extent of tissue desobstruction is described based on a minimum cost algorithm for automatically detecting the contours of complex structures produced by intra-arterial visualization techniques.