Automated method for left ventricular volume measurement by cineventriculography with minimal doses of contrast medium.

Cineventriculography is of considerable value in the dimensional analysis of the left ventricular cavity, but conventional methods necessitate injection of large amounts of contrast medium. In this study, small dose left ventriculography, using only 5 ml of dye, was performed in order to minimize the untoward effects of contrast medium. A computer-aided image processing system was also developed to enhance the contrast of the ventricular image by subtracting the reference image to eliminate irrelevant background. The boundary of the left ventricular cavity was automatically determined to calculate the instantaneous volume change throughout the cardiac cycle. With use of this small dose of dye, the elevation of left ventricular end-diastolic pressure that consistently occurred 1 to 3 minutes after injection of conventional large doses could be avoided. (End-diastolic pressure at 1 minute after dye injection averaged 11.8 +/- 4.9 [mean +/- standard deviation] for small dose and 19.1 +/- 6.1 mm Hg for large dose injection.) Values for end-diastolic volume, end-systolic volume and ejection fraction calculated from the two consecutive small and large dose left ventriculograms in 16 patients were similar. Thus, minimal doses of contrast medium permit accurate measurement of left ventricular dimension and function without significant hemodynamic derangement. The optimal projection for regional wall motion analysis can easily be selected by this method with repeated exposure at various degrees of obliquity. With this technique, even noninvasive measurement of left ventricular volume can be provided by intravenous injection of small doses of contrast agent.