Noninvasive Assessment of Arterial Heart Valves

Cracks in Bjork-Shirley heart valves lead to the death of many patients. Only X-ray technique showesuccess for the detection of fractures in implanted valves. We will use a magnetic technique which inon- invasive for crack detection in implanted valves. We will apply in ac magnetic field to the impthe response from the valves with a Superconducting Quantum Interference Device (SQUID), the most sefield sensors. We will monitor the phase shift between the detected signal and the applied field. Thvalve will be different from an intact one, and will introduce dramatic differences in the corresponPreliminary tests at Quantum Magnetics have demonstrated this detection principle on samples simulatoutlet struts. In Phase I research we will modify our existing instrument to study replacement valveof a human body, and also inside live sheep, assisted technically by Shiley Research Center. We willfrom different size valves and different fractures under various environments. In Phase II we will dcomplete system for the inspection of replacement valves.