Improved Accuracy by Transthoracic Three-dimensional Echocardiography with Harmonic Imaging for Assessment of Left Ventricular Volumes:Comparison with Magnetic Resonance Imaging

Background: Three-dimensional echocardiography (ECHO) eliminates geometrical assumptions in estimation of left ventricular (LV) volumes and may in conjunction with harmonic imaging which improve delineation of endocardial borders increase accuracy and reduce variability in LV volume estimation. Methods: Thirteen consecutive patients with severely reduced left ventricular function and dilated hearts (11 males, 12 with ischémie heart disease and one with cardiomyopathy) were included in the study. LV volumes were measured independently by multislice magnetic resonance imaging (MRI) and transthoracic threedimensional ECHO (GE-VINGMED, System V) using standard fundamental B-mode imaging and tissue harmonic imaging. Volume calculations were done by two of the authors in order to assess interobserver variability . The agreement between ECHO and MRI, and interobserver variability for determination of EDV, ESV, and EF were estimated. Thus, the mean difference between the two measurements ±2SD of the differences expressed as a percentage of the average values were calculated. Results: Compared with fundamental imaging, tissue harmonic imaging showed a closer agreement to MRI and less interobserver variability in estimation of left ventricular volumes(see table). Harmonic imaging Fundamental imaging MRI-ECHO Interobserver MRI-ECHO ItUerobserver Mean±2SD (%) EDV -1. 9+9. 7 -0. 3±5. 6 -10. 8±17. 5* 5. 5±I3. 9* ESV 0. 4±9. 3 0. 7±10. 8 -6. 3±22. 0* 0. 5+18. 7 EF -t. 5±6. 3 -0. 7±. 6. 4 -2. 8±12. 1 2. 6±13. 7*P0. 05 Harmonic versus fundamental imaging Conclusions: Tissue harmonic imaging in combination with threedimensional reconstruction shows low interobserver variability and is a very accurate method for assessment of LV volumes in patients with heart failure and LV dilatation.