Julio E. Perez, M.D.

DEPARTMENT OF Internal Medicine
Keywords: clinical research, imaging

There is considerable interest in the development of effective noninvasive means of estimating the extent of myocardium at risk of undergoing irreversible ischemia in patients with coronary artery disease. This motivation responds to the need of clinicians to better understand the impact of restoration of coronary blood flow in patients afflicted with myocardial ischemia or infarction. In this research, quantitative techniques for myocardial tissue characterization via ultrasonic imaging have been developed and refined in a collaborative effort with Dr. James G. Miller from the Department of Physics. Methodology and applications continue to be an area of intense laboratory animal and clinical investigation. The current goal is to develop approaches for the description of the physical state of myocardium, based on ultrasonic imaging (echocardiography) that can be used at the bedside of critically ill patients to recognize with sufficient diagnostic power the characteristics of viable myocardium, perhaps irrespective of its mechanical function or dysfunction. In this context, characterization of myocardium via the analysis of the radiofrequency ultrasonic signals that emanate from tissue after insonification offers the ability to quantitate the signal as it relates to the intramyocardial structure on the segment being studied. Extension of the same image processing has permitted the frame-by-frame detection and tracking of cardiac endocardial/blood boundaries in echocardiographic images to allow instant quantification of cardiac dimensions (chamber areas and volumes) and functional indexes (ejection fraction, pressure-dimensions relationship) in real time. This latter technologic development has been introduced in clinical practice with widespread application. Furthermore, advances in ultrasonic image processing and refinement in microbubble contrast agents for intravenous injection in patients have permitted echocardiographic simultaneous assessment of myocardial function and perfusion. These areas of clinical investigation are actively pursued at the present time in our laboratory.