[Evaluation of left ventricular volumes in patients with congenital heart disease and abnormal left ventricular geometry. Comparison of MRI and transthoracic 3-dimensional echocardiography].

PURPOSE: To assess the new method of 3-dimensional echocardiography in comparison to the "gold standard" MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease.

MATERIALS AND

METHODS

Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8 +/- 9.7) with a geometrically abnormal left ventricle were examined using a 1.5T scanner with a fast gradient-echo sequence (TR = 14 ms, TE = 2.6 - 2.9 ms, FOV = 300 - 400 mm, flip angle = 20 degrees, matrix = 128 : 256, slice thickness = 5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec (Munich, Germany) system for 3D reconstruction.

RESULTS

Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 of 18 patients (61 %) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, the correlation was r = 0.97 for the end-systolic volumes, r = 0.98 for the end-diastolic volumes, r = 0.79 for the end-systolic muscle mass and r = 0.77 for the end-diastolic muscle mass. The agreement between both methods was considered good for the calculated end-diastolic volumes and sufficient for the calculated end-systolic volumes. The muscle mass calculations showed larger differences especially for the end-systolic mass. Mean intraobserver variability was 18.6 % for end-systolic and 8.3 % for end-diastolic volumes.

CONCLUSION

In patients with an abnormal left ventricular configuration due to congenital heart disease, the new method of 3D-echocardiography is sufficient for volume calculations in preselected patients. The high intraobserver variability is still a limitation of transthoracic 3D-echocardiography in comparison to MRI.