Do not mistake aorta for the IVC
Confusing the aorta with the inferior vena cava (IVC) is a frequent error that may result in improper patient management. It is essential to consistently trace the IVC upwards and confirm its connection with the right atrium. Additionally, whenever feasible, attempt to identify the junction of the hepatic vein and IVC. The subsequent table and figure outline further significant distinctions between these two vessels.
In the following sonographic image, the initial vessel is aorta (note anterior branches) and as we fan the probe towards the right, IVC emerges. Hepatic vein joining the IVC can be seen. This image also illustrates how IVC passes ‘through’ the liver while aorta is by the side (= there is some gap between the aorta and the liver).
Here is a nice example showing IVC entering the right atrium (RA). Also note the hepatic vein, tricuspid valve. Occasionally, you may find tricuspid valve vegetation in this view!
Pulsatility should NOT be used to differentiate IVC and aorta. Contrary to popular perception, IVC is often pulsatile, more so in hyperdynamic states (e.g., sepsis, volume depletion, cirrhosis) and tricuspid regurgitation. Below is a nice example demonstrating pulsatile IVC.