3aPAa6. Noninvasive spatially contained high-power ultrasonic system (NSHUS) for blood clot disintegration.

Session: Wednesday Morning, May 15

Author: Willem Grandia
Location: QMI, Costa Mesa, CA 92627
Author: Robert J. Siegel
Location: Cedars--Sinai Med. Ctr., Los Angeles, CA 90048
Author: Yoseph Bar-Cohen
Location: California Inst. of Technol., Pasadena, CA 91109-8099


Ultrasonic waves can be focused from a point outside of the body to an internal blood clot without using invasive techniques. Noninvasive focused ultrasonic techniques for blood clot disintegration may allow for prompt treatment, and eliminate the need for costly and time-consuming invasive catheter-based interventions. Thus this noninvasive approach using therapeutic ultrasound could greatly reduce patient mortality, morbidity, duration of hospitalization, convalescence, and cost of care. An ultrasonic system was designed to operate from 25--200 kHz and provide a localized high power. The profiles of the field and localization effects were analyzed to optimize power containment to the area of the blood clot. To demonstrate system performance tests were initially made to dissolve sugar blocks mounted in an ice/water bath. At this water freezing point, conditions of 0 (degrees)C, the rate of sugar dissolution is very slow and it provided a baseline as a measure of ultrasound effect. Various ultrasonic frequencies and power levels were introduced to determine the ultrasonic dissolution/disintegration capability. Simulated blood clots were then exposed to the localized high power and the characteristics of the disintegration as a function of power and frequency were examined. The duration of exposure has been a key parameter in this investigation.

from ASA 131st Meeting, Indianapolis, May 1996