Videodensitometric Quantitation of Left-to-Right Shunts with Contrast Echocardiography

Abstract

Contrast echocardiography is a sensitive indicator of intracardiac shunts. It has allowed the precise definition of the site of intracardiac shunts and visual, subjective assessment of shunt size [1, 2]. A photometric analysis of two-dimensional echocardiography has demonstrated indicator-dilution type curves for assessment of appearance and disappearance with time [3]. Previously, our group [4] reported an attempt to quantitatively assess shunt size. We applied computer-based roentgen videodensitometric techniques to video recordings of contrast two-dimensional echocardiography to quantitate left-to-right shunts. For this preliminary study, patients with ventricular septal defect were selected for assessment of shunt size, because comparative data would be available during cardiac catheterization [4]. For contrast two-dimensional echocardiography, indocyanine green dye (1 ml) with a sahne flush was selectively injected by catheter into the left ventricular cavity. Parasternal long-axis and short-axis scans, as well as subxiphoid and suprasternal scans, were recorded with sequential dye injections. Two-inch videotape recordings were obtained and subsequently transferred to video disc for replay.