Validation of 3D echocardiographic volume detection of left atrium by human cadaveric casts.

BACKGROUND: Left atrial volume is a prognostic factor in cardiac pathologies. We aimed to validate left atrial volume detection with 3D and 2D echocardiography (3DE and 2DE) by human cadaveric casts. 3DE facilitates measurement of atrial volume without geometrical assumptions or dependence on imaging angle in contrast to 2DE methods. METHODS: For method validation, six water-filled balloons were submerged in a 20-l water tank and their volumes were measured with 3DE. Seven human cadaveric left atrial casts were prepared of silicone and were transformed into ultrasound-permeable casts. Casts were imaged in the same setting, so that 3DE and 2DE of casts represented transthoracic apical view. Left ventricle analysis softwares GE 4D Auto LVQ and TomTec 4D LV-Function were used for 3DE volumetry. RESULTS: Balloon volumes ranged 37 to 255 ml (mean 126 ml). 3DE resulted in an excellent volumetric agreement with balloon volumes, absolute bias was - 3.7 ml (95% CI -5.9 to - 1.4). Atrial cast volumes were 38 to 94 ml (mean 56.6 ml). 3DE and 2DE volumes were excellently correlated with cast volumes (r = 0.96 to 0.99). Biases were for GE 4D LVQ -0.7 ml (95% CI -6.1 to 4.6), TomTec 4D LV-Function 3.3 ml (- 1.9 to 8.5) and 2DE 2.9 ml (- 4.0 to 9.9). 3DE resulted in lower limits of agreement and showed no volume-related bias in contrast to area-length method. CONCLUSIONS: We conclude that measurement of human cadaveric left atrial cast volumes by 3DE is in excellent agreement with true cast volumes.

Evaluation of cardiac biventricular segmentation from multiaxis MRI data: a multicenter study.

PURPOSE: To validate a volumetric biventricular segmentation solution for multiaxis cardiac magnetic resonance (CMR) images. MATERIALS AND METHODS: The study population comprised 40 subjects. Biventricular end-diastolic and -systolic phases were segmented from both short-axis and horizontal long-axis or transaxial cine CMR images. Segmentation was based on fitting nonrigidly a 3D surface model to multiaxis CMR images. Five segmentations were performed: two manual segmentations by experts, automatic segmentation, and two segmentations where a user was allowed to correct errors in the automatic segmentation for 2 minutes and without time limits. Volumetry, distance measures, and visual grading were used to evaluate the quality of the segmentation. RESULTS: No difference was observed between automatic and manual segmentations in volumetric measures of the ventricles. The manual segmentation performed better for left-ventricular myocardial volume. The distance between surfaces as well as visual analysis did not show differences between automatic and manual segmentation for the endocardial border of the left ventricle but some corrections are needed for the right ventricle. CONCLUSION: Fully automatic segmentation produces good results in the assessment of left ventricular volume andendocardial border. Two minutes of user interaction are needed to obtain accurate results for the right ventricle.