使用3D超声心动图对右心室进行形态学和功能评估

Numerous clinical studies highlighted the diagnostic and prognostic role of right ventricle morphology and function, showing the need for detailed quantification of structure and function of the chamber. Compared to its left counterpart, the right ventricle has a much more complex anatomy and motion pattern. Therefore, only 3D acquisitions provide the opportunity of adequate volumetric measurements.

3D echocardiographic assessment of the right ventricle is a precise, fast and highly reproducible technique with an established added clinical value in a wide variety of diseases. Beyond right ventricular measurements, 3D acquisitions give the opportunity of three-dimensional left ventricular or even heart in the same setting. Compared to the traditional echocardiographic examination, three-dimensional measurements require a slightly different approach.

Nevertheless, the currently available semi-automatic methods facilitate an easy implementation through everyday clinical practice For the acquisition of 3D images, confirm the correct right ventricle focused view from the 2D echocardiography images. If the free wall of the right ventricle is poorly visualized in this view, the expected 3D image quality will not be optimal for further analysis. If the image is acceptable, use the 4D button to switch to live 3D imaging and use the 12-slice mode for the 3D view to acquire a triplane image of the region of interest, as well as nine cross-sectional planes that can be freely modified.

By rotation and correct positioning of the cut planes, confirm the visibility of the entire right ventricle free wall, including the outflow tract and apical segments, and use the left tilting of the sector to further adjust the image. Using the single-beat mode, select an optimal image depth, width, and frame rate and obtain 3D loops of the right ventricle. Using the multi-beat mode, reconstruct the acquired 3D loop from a given number of heart cycles.

When the acquired 3D volume has been stitched together, position the probe at the region of interest and ask the patient to take and hold a deep breath. The expanding lungs will typically cover the entire image. Ask the patient to exhale slowly.

As the lungs deflate, the right ventricle should become visible again. When the entire right ventricle free wall and septum reappear, ask the patient to hold their breath in this state. Select multi-beat and begin the acquisition.

The 3D loops will build up during the select number of heart cycles. When the entire right ventricle can be visualized, instruct the patient to breathe freely again. Then check the obtained loop to confirm that there are no stitching or dropout artifacts.

For 4D right ventricle analysis, open the right ventricle-focused 3D loop from the patient library in the appropriate 4D analysis software program and orient the right ventricle on four predefined cut planes. Place two markers to the center of the tricuspid valve in the upper and lower left long axis planes and use the rotation tool to adjust the long axis of the image to the actual long axis of the right ventricle. Reference images on the upper right edges show how the correct orientation should appear.

In the upper and lower right panels, use rotation to align the short axis images into the correct position using the reference images as a guide. Click set landmarks to set landmarks in two images, and mark the tricuspid annulus at the tricuspid valve free wall and septum and the right ventricle apex on the previously oriented apical four-chamber view. On the right side, set the right ventricle posterior and anterior insertion points and the right ventricle free wall using the reference images as a guide.

When all of the landmarks have been set, the software will automatically jump to the review window. Review and manually correct the automatic endocardial border detection throughout the entire cardiac cycle as necessary. In the case of false tracking, click the endocardial borders to correct them as necessary.

Using the rotation tool on the short axis, track along the entire circumference of the right ventricle to review the images. Select pen size to adjust the magnitude of correction. When the tracking is correct, click results and review the final 3D volumetric data and other calculated parameters in the worksheet panel.

If further adjustments are needed, click on the appropriate parameter to make a modification. If the tracking and the 3D parameters appear to be valid, click approve and exit to save the values. Three dimensional analysis of the right ventricle is feasible in a wide variety of cardiovascular diseases.

For example, these images were taken in a healthy volunteer with normal ventricular volumes and function. These images acquired in a post mitral valve repair patient provide a typical example of the conflicting results of conventional 2D assessment. While tricuspid annular plane systolic excursion was markedly reduced, the patient did not exhibit any signs of right ventricle dysfunction and maintained right ventricle global systolic function, as confirmed by a normal 3D right ventricle ejection fraction.

In this semi-professional athlete with dilated cardiomyopathy, only a moderate image quality was achievable, resulting in a poorly visualized outflow tract. Three-dimensional right ventricle analysis was successful, however demonstrating good agreement with cardiac MR results. Using the currently available software solutions, 3D right ventricular assessment became easier than ever before.

Still, the key for a precise and reproducible analysis is the proper acquisition at bedside. The added clinical value of three-dimensional right high parameters is no longer a question. Beyond being a fascinating research tool, these measures are part of the state-of-the-art patient management, as well.