3-DIMENSIONAL ECHOCARDIOGRAPHIC EVALUATION OF LEFT-VENTRICULAR VOLUME- COMPARISON OF DOPPLER MYOCARDIAL IMAGING AND STANDARD GRAY-SCALE IMAGING WITH CINEVENTRICULOGRAPHY - AN IN-VITRO AND IN-VIVO STUDY

Background Standard gray-scale imaging (GSI), three-dimensional (3D) e chocardiography has been shown to be superior to two-dimensional echoc ardiography in measuring left ventricular volume. However, the often r elatively poor quality of transthoracic gray-scale data can limit the potential application of this technique. Doppler myocardial imaging (D MI) is a new ultrasound technique that potentially offers higher-quali ty 3D images with a transthoracic approach than the 3D GSI technique. This study was designed to compare the accuracy of standard GSI and DM I 3D left ventricular volume measurements in vitro and in vivo. Method s and Results In vitro, the minimum and maximum volume of the contract ing single-chamber, tissue-mimicking phantom was calculated by using b oth techniques. In vivo, GSI and DMI 3D left ventricular volume measur ements were performed in 16 patients. End-diastolic and end-systolic l eft ventricular volumes were computed for both techniques and compared with those calculated by cineventriculography. In vitro, both methods tended to underestimate the true phantom volume, but the systematic e rror was smaller for DMI than for GSI (-1.2% +/- 1.5% vs. -4.3% +/- 3% ; p < 0.01) and was more constant in the case of DMI over the range of different sizes of true volume. In vivo, for GSI the end-diastolic vo lume mean difference was -12.6 ml and the limits of agreement were +/- 18 ml, and for DMI the corresponding values were -4.2 and +/-10.6 ml, respectively. The difference for end-systole was -6.5 +/- 10.6 ml and -1.5 +/- 10 ml for GSI and DMI, respectively. The magnitude of the di fference in volume measurement between 3D echocardiography and cineven triculography was significantly smaller when using the Doppler techniq ue. Conclusions The results of this in vitro and in vivo study indicat e that DMI is superior to GSI as a transthoracic acquisition technique for 3D volume computation.