3D echocardiography has arrived into clinical practise after a long wait. It is however a newer technology that requires much skill and patience, and there is limited mainstream experience. Echopraxis reviews 3d Echocardiogrpahy and its relevance to critical care echocardiographers.
Origins: 2D echocardiography has been the mainstay of echocardiography since the 1970s. Multiplane echocardiography began in ernest in the 1990s, but it wasn’t until the year 2000 that sample matrix array scanners came on to the market.
Potential advantages: 3D echocardiography is theoretically very appealing. With 3D you are able to calculate actual volumes of chambers, multiplane acquisition from a single footprint, and with automation, potentially scan with shorter time and with higher reproducibility. Furthermore, anatomical structures can be assessed with a more “realistic” representation.
Problems: The technology was initially clumsy, slow, and suffered from many additional artefacts. For example, stitching occurs when multiple separate slices of an image (taken over multiple beats) are stitched together but the layering is disjointed causing image distortion . Huge processing demands also resulted in poor temporal and spatial resolution, making interpretation very difficult.
TOE showing the normal mitral valve in 3d. The leaflet at 12 o’clock is the anterior mitral valve while the smaller leaflets at 4 and 7 is the posterior mitral valve.
The technology has rapidly evolved however, and now real time 3d echo is possible, allowing live 3d imaging, especially if used in a correct manner – i.e. zooming into the area of interest, or using a narrower field of view. Furthermore, rapid improving in computer processing speeds has meant many of the processing power problems have been overcome.
TOE showing mid oesophageal view of the Aortic valve in short axis. Severe Aortic Stenosis.
Intraoperative 3d TOE showing mitral valve in short axis post mitral valve repair.
Where are we at in 2015? 3D echo has rapidly become part of the routine cardiology landscape. The EAE-ASE-recommendation-image-acquisition-3D-echo suggest that 3d Echo is now the RECOMMENDED echo modality for LV volume and EF, assessment of the mitral valve, and guidance of transcatheter procedures (such as TAVI). It states further that areas with promising clinical studies are LV mass, RV volume and EF, and the assessment of the Aortic valve.
In the critical care setting, intraoperative TOE using 3d assessment of the heart – particularly in assessment of valves, has become routine in many centres. Further filtering into the critical care ultrasound community is also occurring and likely to continue.
3d echo has taken a long time to become clinically relevant, but that time is now – and a future that is not rich in 3d echo is hard to see.