Ultrasonic based detection of interventional medical device contact and alignment

Abstract

A method and apparatus for remotely monitoring the location of an interventional medical device (IMD) using ultrasonic signals. Both the proximity and alignment of the IMD are calculated from ultrasound signals reflected off the tissue surface. The inclusion of an offset between the distal end of the IMD and the ultrasound transducer enables accurate position and alignment monitoring of when the IMD is in contact with, or very close to, the tissue surface. The timing of the reflected signal is used to measure proximity or contact. A comparison of the strength between multiple reflected signals is used to measure the alignment of the IMD in 3D space or perpendicularity to a given surface. The present invention may be used as a location indicator within a wide variety of IMDs, and in a wide variety of medical procedures.