Every few years, technological advancements come along that provide critical improvements in the way we perform cardiac procedures by giving us the tools to make more accurate diagnoses.
One such advancement is Live 3D Echo. While threedimensional (3-D) technology in cardiac ultrasound is not a new concept ├óÔé¼ÔÇ£ it has been well known as a clinical application for the last 12├óÔé¼ÔÇ£13 years ├óÔé¼ÔÇ£ the use of Live 3D as a clinically viable application is new. Historically, 3-D echocardiography involved the compilation of multiple 2-D images. However, the overall image acquired was not in realtime.
That has all changed within the past 18 months as technology has evolved to make realtime imaging in 3-D possible. As a result, we are now able to diagnose potentially life-threatening medical conditions in realtime, and doctors are better able to communicate the diagnosis and make recommendations for treatment without any guesswork.
The importance of realtime 3-D cannot be emphasised enough. It gives us different levels of knowledge ├óÔé¼ÔÇ£ such as viewing and diagnosing problems with the mitral valve ├óÔé¼ÔÇ£ that could not be obtained before. It is the realtime aspect of this technology that is critical in obtaining a precise diagnosis.
The Evolution of 3 - D
As clinicians sought methods to capture Live 3D views to explore the complexities and interrelationships of the heart, they discovered numerous technical hurdles, since extremely high frame rates were required to capture the cardiac motion.
To appreciate the clinical significance of Live 3D Echo, it is important to look at how 3-D has evolved. Early echocardiographic systems relied on m-mode displays that were accurate in the axial dimension only. While sample rates may be low, information obtained from these images was extremely limited.
Two-dimensional echocardiography has been a known technology for 30-40 years. Twodimensional imaging provided a significant improvement in the ability to obtain data, making it possible to scan and view planes of the heart in such a way that clinicians could visualise the anatomy of the heart. Using 2-D, clinicians could see both the axial and lateral dimensions, and realtime 2-D provided information about the 2-D orientation of the heart's anatomy. However, 2-D also had limitations. Since clinicians were viewing slices of the heart, they were unable to see through these walls and were not able to view the entire heart. Therefore, relying on 2-D became somewhat subjective and depended on the imagination of the person acquiring the images as clinicians were left to deduce what the complete heart image looked like. The difference between 2-D and 3-D is similar to the difference between plain X-ray and computed tomography.
Three-dimensional echocardiography moved a step closer to reality with the adoption of the transoesophageal echo (TEE) probe, which enabled clinicians to gain a new perspective in cardiac imaging by scanning the heart from the oesophageal location, which is immediately next to or behind the heart. The OmniPlane TEE probe also brought the ability to acquire multiple images of the heart from different planes for reconstruction and rendering of a triggered 3-D image. While this offered an opportunity to view the heart in 3-D using ultrasound, it also had limitations, including lack of realtime interaction of the 3-D image. Imaging modes with the biggest impact in echocardiography all have one thing in common: realtime imaging. Every mode interacting with the image in realtime allowed for immediate decision-making.
Triggered 3-D imaging required an acquisition protocol that took many beats and required many minutes to acquire the images. The acquired data set was transferred to an offline software workstation that reconstruc