3D Mode

 
3D Mode
 
3D is a new mode recently available in some echocardiography machines. While 2D mode will cut a slice across anatomical structures and show them in real-time, 3D can also show structures in real time with less resolution but with depth. The 3D volume set can be rotated in 3D space to inspect structures and/or jets. 3D is currently just presenting itself as a useful tool that can be applied in certain situations in echocardiography.
 
 
 
 
 
 
 
3D Real Time (3DRT) scans a sector in one cardiac cycle or in a gated acquisition of multiple beats and displayed on the monitor. If the acquisition is gated, the 3D volume set will be scanned in pyramid tomographic cuts of the full volume set and stitched together electronically. The resulting scan is sent to the echocardiography machine for digitization and presented as a single loop. 3D can also be used with color Doppler to show a 3D image of a jet or shunt.
 
 
 
 
The 3D scan appears to be colorized, but, the distal structures are more blue and the more proximal structures are more red. A flail mitral valve leaflet will appear red while the rest of the mitral valve appears blue (if distal in the scan area) or yellow (if in the middle of the scan area). The mid point of the scan area appears to be fixed and is similar to the focal point in a 2D scan. The red-blue color map only signifies the location of a structures depth, not it's velocity.
 
 
 
 
The 3D scan relays a lot of information to the CPU for processing. Therefore, only proximal structures have acceptable resolution. Distal structures from the TEE probe such as the tricuspid valve (lots of structures to scan through) or the aortic valve (distally located) will relay so much information that much of the structure may not appear (drop out). While drop out from 2D scans is either due to parallel oriented structures or some intervening specular reflector, 3D scan appear to suffer from information overload. If the scan is a wedged shaped cone 5 cm deep and 60 degrees wide, the volume of the scan could be doubled just by increasing the depth to 6 cm. Twice as much information returned will result in a lower resolution scan.