NONINVASIVE DETECTION OF MICROEMBOLI

BECAUSE PRESENT METHODS FOR DETECTION OF PULMONARY EMBOLI UTILIZE IMAGING TECHNIQUES, THE SIZE OF EMBOLI DETECTABLE BY THESE METHODS IS LIMITED BY THE INHERENT SPATIAL RESOLUTION OF X-RAY AND GAMMA CAMERAS. MICROEMBOLI (CLOTS OF THE MICROCIRCULATION) ARE THEREFORE TOO SMALL TO BE DETECTED BY STANDARD METHODS. BECAUSE MICROEMBOLI ARE NOT DETECTABLE, THERE IS NO DIRECT EVIDENCE THAT MICROEMBOLIINVOLVEMENT IS OF CLINICAL SIGNIFICANCE. HOWEVER, MICROEMBOLIC INVOLVEMENT HAS BEEN PROPOSED AS A PRINCIPAL CAUSATIVE FACTOR IN ADULT RESPIRATORY DISTRESS SYNDROME (ARDS), A TRAUMA-ASSOCIATED DISEASE HAVING A HIGH MORTALITY (OVER 50 PERCENT) IN YOUNG ADULTS. MICROEMBOLIC INVOLVEMENT IN OTHER TRAUMA-ASSOCIATED CONDITIONS, INCLUDING SURGERY, IS ALSO SPECULATIVE. THE PURPOSE OF THIS PROPOSAL IS TO ESTABLISH THE FEASIBILITYOF APPLYING A NEW AND NONINVASIVE METHOD TO THE DEVELOPMENT OF A PRACTICAL INSTRUMENT FOR SENSITIVE AND QUANTITATIVE DETECTION OF MICROEMBOLIC INVOLVEMENT IN HUMAN LUNGS. PHASE I WILL ADDRESS VALIDATION OF THE PRINCIPLE OF THE NEW METHOD IN EXPERIMENTAL ANIMALS. THE ECONOMIC GOAL OF PHASE II WILL BE TO TEST THE LIKELIHOOD OF MICROEMBOLIC DETECTION BECOMING A STANDARD MEDICAL PRACTICE. ACCOMPLISHMENT OF THIS GOAL WILL INVOLVE A COMBINATION OF TECHNICAL DEVELOPMENT AND SCIENTIFIC STUDIES. GIVEN A SUCCESSFUL PHASE I, PHASE II WILL (1) DEVELOP A PRACTICAL INSTRUMENT FOR HUMAN STUDIES, AND (2) PERFORM CLINICAL RESEARCH STUDIES DESIGNED TO VERIFY THE MICROEMBOLIC INVOLVEMENT IN ARDS AND OTHER TRAUMA-ASSOCIATED CONDITIONS.