ABSTRACT
PURPOSE: Quantification of the left ventricular (LV) volume by three-dimensional echocardiography is accurate but time-consuming. To shorten the time required, we sought to determine the minimum number of image planes necessary to measure LV volume reliably. METHODS: We analyzed transesophageal three-dimensional echocardiographic LV data obtained by the rotational scanning method in 16 patients: 11 had ischemic heart disease, and 5 had dilated cardiomyopathy. LV volumes were calculated from 6, 10, and 30 short-axis images using the disk-summation method and from 2, 4, 6, 10, 20, and 30 longitudinal images using the new average rotation method. RESULTS: LV volume varied less with the average rotation method than with the disk-summation method. The 95% limit of agreement between the 30-image and 6-image methods was 0.3% ± 3.7% for the average rotation method, whereas it was -2.0% ± 6.9% for the disk-summation method. The time required for analysis decreased from 12.5 ± 2.8 min with the 30-image method to only 3.3 ± 0.5 min for the 6-image method. CONCLUSIONS: Measurement of six longitudinal images provided reliable LV volume data, even in patients with enlarged or deformed left ventricles. The short measurement time supports the use of three-dimensional echocardiographic LV volume measurement in the clinical setting.
ABSTRACT
Aortic stenosis is a challenge for three-dimensional (3-D) echocardiographic image resolution. This is the first study evaluating both 3-D anyplane and 3-D volume-rendered echocardiography in the quantification of aortic stenosis. In 31 patients, 3-D echocardiography was performed using a multiplane transesophageal probe. Within the acquired volume dataset, five parallel cross sections were generated through the aortic valve. Subsequently, volume-rendered images of the five cross sections were reconstructed. The smallest orifice areas of both series were compared with the results obtained by two-dimensional (2-D) transesophageal planimetry and those calculated by Doppler continuity equation. No significant differences were found between Doppler (0.76 +/- 0.18 cm(2)), 2-D echocardiography (0.78 +/- 0.24 cm(2)), and 3-D anyplane echocardiography (0.72 +/- 0.29 cm(2)). The orifice area measured smaller (0.54 =/- 0.31 cm(2), P < 0.001) by 3-D volume-rendered echocardiography. Bland-Altmann analysis indicated that for 3-D anyplane echocardiography, the mean difference from Doppler and 2-D echocardiography was - 0.04 +/- 0.24 cm(2) and - 0.06 +/- 0.23 cm(2), respectively. For 3-D volume-rendered echocardiography, the mean difference was -0.23 +/- 0.24 cm(2) and - 0.25 +/- 0.26 cm(2), respectively. In the subgroup with good resolution in the 3-D dataset, close limits of agreement were obtained between 3-D echocardiography and each of the reference methods, while the subgroup with poor resolution showed wide limits of agreement. In conclusion, planimetry of the stenotic aortic orifice by 3-D volume-rendered echocardiography is feasible but tends to underestimate the orifice area. Three-dimensional anyplane echocardiography shows better agreement with the reference methods. Accuracy is influenced strongly by the structural resolution of the stenotic orifice in the 3-D dataset.
