Advances in Echo Imaging Using Contrast Enhancement [antikvár]

1. Contrast echocardiography - a historical perspective PRAVIN M. SHAH 1. THE BEGINNING YEARS Nearly 25 years ago, Dr. Raymond Gramiak and I embarked on a study, using M-mode echocardiographic recordings of the aortic valve to estimate stroke volume from extent and duration of aortic cusp separation. We proceeded to record the aortic valve and root echo simultaneously with measurements of cardiac outputs using the indicator-dilution technique in the cardiac catheterization laboratory. It was then a routine practice at the University of Rochester to place a catheter in the left atrium by transseptal technique and measure cardiac output by injection of indocyanine green in the left atrium with peripheral arterial sampling. It was in the performance of these studies that a striking enhancement of echo signals was observed, and this was termed contrast echocardiography following an analogy with the term "contrast angiography" applied to radiographic procedures. We observed this contrast echo effect with indocyanine green injections, as well as with saline or dextrose in water flush of the catheters. This observation reminded Dr. Gramiak of a passing comment by Dr. Claude Joyner at the First International Course on Diagnostic Ultrasound of the echo enhancement could be observed with saline injections. Although his observation was not in print, our first published report in 1968 [1] dealing with the M-mode echocardiography of the aortic root credited Dr. Joyner with the observation. We utilized contrast echocardiography in order to validate the echo recordings of the aortic root and valve. A systematic prospective study was then undertaken, and the results of 242 injections of echo contrast in 32 patients during diagnostic cardiac catheterization were reported in 1969 [2]. The contrast substances employed were indocyanine green solution, saline, 5% dextrose in water, and the patient's own blood. The injection sites included both atria, both ventricles, and the aortic root. This being the pre-strip chart era, we obtained continuous recordings of the combined ultrasonic and physiologic display on 35 mm film by means of a Fairchild Oscilloscope Record Camera. The echo anatomy I" i: P . I;/' N. Nanda and R. Schlief (eds.). Advances in Echo Imaging Using Conirosl Enhancement. 3-8. © 1993 Kluwer Academic Publishers. Primed in the Netherlands.