Original article
Quantification of Regional Left Ventricular Wall Motion from Real-time 3-Dimensional Echocardiography in Patients with Poor Acoustic Windows: Effects of Contrast Enhancement Tested Against Cardiac Magnetic Resonance

https://doi.org/10.1016/j.echo.2006.02.010Get rights and content

Objective

Regional left ventricular function can be assessed by real-time 3-dimensional echocardiography (RT3DE) in patients with good image quality. Our goals were to: (1) test the feasibility of RT3DE quantification of regional wall motion (RWM) in patients with poor acoustic windows who require contrast for endocardial visualization; and (2) validate these measurements against cardiac magnetic resonance (CMR) reference.

Methods

RT3DE datasets and CMR images were obtained in 24 patients. In 16 of 24 patients with suboptimal endocardial definition, RT3DE imaging was repeated with intravenous contrast and triggering at end systole and end diastole. RT3DE datasets were analyzed using custom software designed to semiautomatically detect and segment the endocardial surface and calculate RWM values. CMR images were analyzed using commercial software to obtain reference values for RWM.

Results

In 8 of 24 patients with good endocardial definition, RT3DE values of RWM correlated well with CMR (r = 0.73) with a small bias (−1.0 mm). In the remaining 16 patients, analysis of nonenhanced RT3DE datasets yielded lower correlation with CMR (r = 0.61) and a slightly greater bias (−1.5 mm). The agreement with CMR improved significantly (r = 0.76, bias −1.1 mm) with contrast enhancement.

Conclusions

The agreement between RT3DE and CMR values of RWM is directly related to RT3DE image quality. In patients with poor acoustic windows, dual-triggered contrast enhancement improves the accuracy of RWM quantification to a level similar to that noted in patients with good images without contrast.

Section snippets

Study Design

Patients referred for CMR evaluation of LV function were studied. Exclusion criteria were: dyspnea precluding a 10- to 15-second breath hold, cardiac arrhythmias, left bundle branch block, prior sternotomy, pacemaker or defibrillator implantation, claustrophobia, and other known contraindications to CMR imaging. Before enrollment, patients were screened by 2D transthoracic echocardiography and divided into two groups. The study group comprised 16 patients (age 57 ± 16 years; 12 men) with

Results

RT3DE imaging and analysis were feasible in all study participants. The average time required for analysis, including data retrieval, frame selection (for nonenhanced datasets only), surface detection and segmentation, and the computation of RWM, was approximately 5 minutes on a 755-MHz Intel Pentium II personal computer (Dell, Round Rock, TX), of which only 30 seconds were required for the computations once user interaction was complete. Figure 2, A, shows an example of an image plane in a

Discussion

Although RT3DE datasets contain volumetric information on LV dynamics, assessment of regional LV function from these images remains subjective. We have recently developed a technique for endocardial surface detection in the 3D domain that fully exploits dynamic volumetric information and allows quantitative analysis of RWM from RT3DE data.8 This new technique was tested and found accurate in patients with good image quality, but its ability to assess RWM in patients with suboptimal images who

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Supported by a Grant-in-Aid from the American Heart Association (Dr Mor-Avi) and a Sonographer’s Grant from the American Society of Echocardiography (Mr Coon).

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