The Use of 3D Echocardiography in Surgical Planning of the Mitral Valve in Pediatric Cardiology

Summary

3D echocardiography of the mitral valve in pediatric cardiology produces full anatomic reconstructions that contribute to improved surgical management. Here, we outline a protocol for 3D acquisition and post-processing of the mitral valve in pediatric cardiology.

Abstract

Mitral valve disease in pediatric cardiology is complex and can involve a combination of annular, leaflet, chordae tendineae and papillary muscle abnormalities. Transthoracic two-dimensional echocardiography (2DE) remains the primary diagnostic imaging technique utilized in pediatric surgical planning. However, given that the mitral valve is a three-dimensional (3D) structure, the addition of 3D echocardiography (3DE) to better define the mechanisms of stenosis and/or regurgitation is advantageous. Transthoracic 3DE technology has improved with advances in probe technology and ultrasound scanners, producing images with good spatial resolution and adequate temporal resolution. Specifically, the addition of pediatric 3D transducers with higher frequencies and a smaller footprint provides better 3DE imaging in children. Improved efficiency of 3DE acquisition and analysis allow 3D assessment of the mitral valve to be more easily integrated by the sonographer, the cardiologist and the surgeon in mitral valve assessment. This improvement was also made possible by the postprocessing software optimization.

In this method paper, we aim to describe the transthoracic 3DE assessment of the mitral valve in children and its use in the surgical planning of pediatric mitral valve disease. Firstly, the 3DE assessment begins by selecting the correct probe and by obtaining a view of the mitral valve. Then, the appropriate data acquisition method should be selected based on the individual patient. Next, optimization of the data set is critical in order to properly balance spatial and temporal resolution. During live scanning or following acquisition, the data set can be cropped using innovative tools that allow the user to quickly obtain an infinite number of cut planes or volumetric reconstructions. The cardiologist and surgeon can view the mitral valve en face; thus, accurately reconstructing its morphology in order to support medical or surgical planning. Finally, a review of some clinical applications is proposed, showing examples in pediatric mitral valve managements.

Introduction

The mitral valve apparatus is a complex structure consisting of the mitral valve annulus, leaflets, chordae tendineae and left ventricular papillary muscles^1,2. Pediatric mitral valve disease consists of an extensive range of morphologic abnormalities associated with congenital and acquired heart anomalies³. The description of the morphology of mitral valve disease and its underlying mechanisms are key parameters for the surgical planning⁴. This requires the use of accurate diagnostic imaging modalities. Echocardiography is established as one of the primary ....

Protocol

This protocol follows the guidelines of our institution's human research ethics committee.

NOTE: For the implementation of this protocol, a General Electric (GE) Vivid E95 or Philips Epiq 7C ultrasound system is used. On the GE Vivid E95 system, the user has a choice between the 4Vc-D (adult probe) or 6Vc-D (pediatric probe). On the Philips Epiq 7C, the user has a choice between the X5-1 (adult probe) or X7-2 (pediatric probe). See Figure 1.

1. Patient setup and probe selection

1. Position the patient in a left lateral decubitus position when possible. See

Results

A good quality 3D data set of the mitral valve in pediatric echocardiography will have an optimal volume rate that is appropriate for assessing leaflet motion and excellent spatial resolution that utilizes superior axial resolution. To assess the success of the protocols 3D ECG gated acquisition, first determine whether any significant "stitch" artifact is present. In the presence of no artifact and if the acquisition was made using an excellent quality 2D low parasternal long-axis view, this 3D data set will pro.......

Discussion

For the operator/sonographer, 3D echocardiography is often met with several challenges. First, by nature there is significant variation in patient size, heart rate and cooperation during a pediatric echocardiography exam. These parameters make it difficult to have 3D specific protocols and therefore make the 3D acquisition operator dependent. Often training for sonographers is focused primarily on 2D imaging, leaving a gap in knowledge with regards to 3D image acquisition and interpretation. In addition, 3D temporal reso.......

Materials

Name	Company	Catalog Number	Comments
4Vc-D probe	General Electric		Ultraspound probe (GE)
6Vc-D probe	General Electric		Ultraspound probe (GE)
Epiq 7C	Philips		Ultrasound system
Vivid E95	General Electric		Ultrasound system
X5-1	Philips		Ultraspound probe (Philips)
X7-2	Philips		Ultraspound probe (Philips)