Visualization of the Coronary Arteries by Two-Dimensional Echocardiography

Abstract

Several investigatots have now demonstrated the ability to use two-dimensional echocardiography to visualize the proximal coronary arteries [1, 2, 3, 4, 5]. The ability to recognize and record the coronary arteries has required many technical advances [6]. One important advance was the use of higher frequency transducers. Merely using a 3 MHz transducer rather than the usual 2.25 MHz transducer used in adult cardiology permits better resolution in examining small structures such as the coronary arteries. A second major advance was the development of a strobe freeze-frame capability [6]. This feature is present on most instruments which use digital scan conversion. With the recordings in a digital form it is possible to use a freeze-frame capability which is gated to the R-wave of the electrocardiogram. Thus, one records only during a selected portion of the cardiac cycle. The recorded image is constantly updated with each subsequent beat. This particular feature is important in examining the coronary arteries because the vessels are constantly moving in and out of the examining plane. One could not hope to track the coronary arteries by rapidly moving the plane of the examination. What in fact happens is that the examiner holds the probe in a stationary fashion in the vicinity of the coronary arteries and the vessels move through the ultrasonic plane. Any given part of the coronary arteries may be recorded only for a very brief period of time with any given transducer position.