COMPARISON OF 2-DIMENSIONAL AND 3-DIMENSIONAL ECHOCARDIOGRAPHY WITH CINEVENTRICULOGRAPHY FOR MEASUREMENT OF LEFT-VENTRICULAR VOLUME IN PATIENTS

Objectives. We compared two- and three-dimensional echocardiography wi th cineventriculography for measurement of left ventricular volume in patients. Background. Three-dimensional echocardiography has been show n to be highly accurate and superior to two-dimensional echocardiograp hy in measuring left ventricular volume in vitro. However, there has b een little comparison of the two methods in patients. Methods. Two- an d three-dimensional echocardiography were performed in 35 patients (me an age 48 years) 1 to 3 h before left ventricular cineventriculography . Three-dimensional echocardiography used an acoustic spatial locator to register image position. Volume was computed using a polyhedral sur face reconstruction algorithm based on multiple nonparallel, unevenly spaced short-axis cross sections. Two-dimensional echocardiography use d the apical biplane summation of disks method. Single plane cineventr iculographic volumes were calculated using the summation of disks algo rithm. The methods were compared by linear regression and a limits of agreement analysis. For the latter, systematic error was assessed by t he mean of the differences (cineventriculography minus echocardiograph y), and the limits of agreement were defined as +/-2 SD from the mean difference. Results. Three dimensional echocardiographic volumes demon strated excellent correlation (end-diastole r = 0.97; end-systole r = 0.98) with cineventriculography. Standard errors of the estimate were approximately half those of two-dimensional echocardiography (end-dias tole +/-11.0 ml vs. +/-21.5 ml; end-systole +/-10.2 ml vs. +/-17.0 ml) . By limits of agreement analysis the end-diastolic mean differences f or two- and three-dimensional echocardiography were 21.1 and 12.9 ml, respectively. The limits of agreement (+/-2 SD) were +/-54.0 and +/-24 .8 ml, respectively. For end-systole, comparable improvement was obtai ned by three-dimensional echocardiography. Results for ejection fracti on by the two methods were similar. Conclusions. Three-dimensional ech ocardiography correlates highly with cineventriculography for estimati on of ventricular volumes in patients and has approximately half the v ariability of two-dimensional echocardiography for these measurements. On the basis of this study, three-dimensional echocardiography is the preferred echocardiographic technique for measurement of ventricular volume. Three-dimensional echocardiography is equivalent to two-dimens ional echocardiography for measuring ejection fraction.