Echocardiographic Assessment of the Tricuspid Annulus: The Effects of the Third Dimension and Measurement Methodology.

BACKGROUND: Evaluation of the tricuspid annulus is crucial for the decision making at the time of left heart surgery. Current recommendations for tricuspid valve repair are based on two-dimensional (2D) transthoracic echocardiography (TTE), despite the known underestimation compared with three-dimensional (3D) echocardiography. However, little is known about the differences in 3D tricuspid annular (TA) sizing using TTE versus transesophageal echocardiography (TEE). The aims of this study were to (1) compare 2D and 3D TA measurements performed with both TTE and TEE and (2) compare two 3D methods for TA measurements: multiplanar reconstruction (MPR) and dedicated software (DS) designed to take into account TA nonplanarity. METHODS: Seventy patients underwent 2D and 3D TTE and TEE. Two-dimensional images were used to measure TA diameter from apical four-chamber, right ventricular-focused (TTE), and midesophageal four-chamber (TEE) views. Three-dimensional full-volume data sets were analyzed using both MPR and DS, to obtain major and minor axes, perimeter, and area. Intertechnique agreement was assessed using Bland-Altman analysis. RESULTS: Measurements on 2D TTE and TEE, which were view dependent, underestimated TA major dimensions in all views compared with 3D values, irrespective of the 3D method. MPR and DS measurements were significantly different, with DS resulting in larger values for all parameters, irrespective of approach. No differences were found between 3D TTE and 3D TEE for both MPR and DS. CONCLUSIONS: Our findings highlight the need for methodology that respects the 3D geometry of the tricuspid annulus, including its nonplanarity, which cannot be accurately assessed from 2D images and is not equally taken into account by different 3D measurement methodologies. Accordingly, a 3D cutoff value for TA enlargement needs to be established and is likely to be larger than the guideline-recommended 2D-based 40-mm cutoff. Importantly, noninvasive 3D TTE can be used instead of 3D TEE because TA measurements are not different.

Automated frame-by-frame endocardial border detection from cardiac magnetic resonance images for quantitative assessment of left ventricular function: validation and clinical feasibility.

PURPOSE: To develop a technique based on image noise distribution for automated endocardial border detection from cardiac magnetic resonance (CMR) images throughout the cardiac cycle, validate it, and test its clinical utility. MATERIALS AND METHODS: Images obtained in 36 patients were analyzed using custom software to obtain left ventricular (LV) volume throughout the cardiac cycle, end-systolic and end-diastolic LV volumes, and ejection fraction (EF). Validation against manually-traced endocardial boundaries included intertechnique comparisons of LV volumes, slice areas, and border positions. Then, the clinical feasibility of the dynamic automated analysis of LV function was tested in 14 patients with normal LV function, 12 patients with systolic dysfunction, and 10 patients with diastolic dysfunction. RESULTS: Analysis time for one cardiac cycle was <15 minutes. Intertechnique comparisons resulted in high correlation (r>0.96), small biases (volumes: -6 mL; EF: 4.6%) and narrow limits of agreement (volumes: 17.6 mL; EF: 9.2%). We found significant intergroup differences in multiple quantitative indices of systolic and diastolic function. CONCLUSION: Fast, automated, dynamic detection of LV endocardial boundaries is feasible and allows accurate quantification of LV size and function, which is potentially clinically useful for objective assessment of systolic and diastolic dysfunction.