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Three-Dimensional Echocardiography: Image Acquisition
Introduction
In the modern echocardiography laboratory, three-dimensional transthoracic echocardiography (3D-TTE) complements the standard two-dimensional transthoracic echocardiographic (2D-TTE) examination. 3D-TTE adds value, improves workflow, and substantially improves accuracy in the quantification of cardiac chambers by avoiding errors inherent in the geometric assumptions made in 2D-TTE ( Figs. 10.1 and 10.2 , and 
). 3D TTE provides a more accurate assessment of cardiac morphology and pathology, native and prosthetic valve structure and function, and guidance in interventional intracardiac procedures.
This chapter presents an overview of the basic 3D-TTE image acquisition and optimization techniques used in the echo lab. Optimal utilization of 3D-TTE requires an understanding of the clinical or research application ( Box 10.1 and Table 10.1 ). A comprehensive understanding of the clinical application helps determine the optimal 3D-TTE technique employed in image optimization, acquisition, rendering, display, and analysis ( Fig. 10.3 and 
, , , , ). The specific clinical applications of 3D-TTE employed in the assessment of cardiac structure and function are covered elsewhere in this book (see Chapter 5 ).
BOX 10.1
Clinical and Research Applications of Three-Dimensional Echocardiography
Clinical and Research Applications
-
Ventricular structure and function: LV, R:
-
Ventricular volumes
-
LV mass
-
LV Geometry/shape
-
LV dyssynchrony
-
Stress echocardiography
-
-
Atria volumes
-
Intracardiac shunts
-
Valvular structure and function:
-
Native valve anatomy
-
Native valve pathology
-
Mitral stenosis, regurgitation
-
Aortic stenosis, regurgitation
-
-
Prosthetic valves
-
Invasive procedures:
-
Transcatheter guidance procedures
-
Intracardiac biopsies
-
Ablation procedures in electrophysiology
-
TABLE 10.1
Examples of Choice of Three-Dimensional Transthoracic Echocardiography Acquisition Mode in the Echo Lab
| Clinical Application | Mode |
|---|---|
| Ventricular volumes (LV, RV) Atrial volumes Ejection fraction Whole heart |
Full volume (wide-angle, multibeat) |
| Valve anatomy Valvular pathology Shunt lesions Small structures visualized within narrow sector |
Live 3D zoom (color) |
| Guidance for transcatheter procedures | Live 3D zoom (color) |
| Native heart biopsies Electrophysiology ablations |
Live 3D |
LV, Left ventricle; RV, right ventricle; 3D, Three-dimensional.
The Three-Dimensional Transthoracic Echocardiography Data Acquisition Protocol
The optimization of both patient and machine preparation for 3D-TTE, consistent with the 2D-TTE examination, is important (see Chapter 11 ). Electrocardiography (ECG) gating is critical for 3D trigger-mode imaging. Therefore it is important to obtain a good ECG signal with clearly visible R-waves. Until recently, the 3D-TTE exam required switching from the standard 2D phased array transducer to a 3D matrix array transducer. Today, the most recent 3D “all-in-one” transducer designs facilitate simultaneous 2D and 3D image acquisition using a single probe. This improves workflow efficiency (see Fig. 10.2 ). The following steps are generally required during 3D-TTE image acquisition ( Box 10.2 ; see also Fig. 10.3 and , , , , ).
- 1.
2D image optimization
- 2.
Acquisition modes
-
Narrow volume vs. wide (full) volume
-
Single-beat vs. multibeat
-
3D zoom
-
3D color
-
- 3.
Rendering
- 4.
Final image display and analysis
BOX 10.2
Typical Workflow in Three-Dimensional Transthoracic Echocardiography
- 1.
Optimize the two-dimensional (2D) images, including imaging depth, sector size
- 2.
Use lower-frequency transducer to improve penetration
- 3.
Apply tissue harmonic imaging
- 4.
Apply automated gain optimization
- 5.
Increase overall gain compensation, usually by more than 50% (55–60 units)
- 6.
Ensure that the region of interest is fully within the scan sector by using multiplane scanning
- 7.
Apply three-dimensional (3D) zoom
- 8.
Optimize box size and position; make sure the region of interest is within the box size range
- 9.
Activate 3D zoom
- 10.
For 3D color zoom, add the color over the selected anatomic area of interest
- 11.
Ensure that the color box occupies the entire selected area
- 12.
Remember the trade-off between image acquisition and frame rate: the larger the area, the larger the volume, the lower the frame rate.
- 13.
If necessary, acquire six-beat electrocardiography data set for higher color frame rates.
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