Imaging the Caudal Vena Cava.

Holding the probe.

The key is holding the probe so your scanning plane cuts through the caudal vena cava (CVC) in its longitudinal scanning plane.  Holding the probe with your hand on top rather than like a pencil keeps the scanning plane “true.”

Best for success!





Note that the hand is on top of the probe with the thumb on the marker and the index finger on the other end in A).  By doing so, the scanning plane is like the piece of paper in B) and in a longitudinal plane.  With this probe handling you can fan in a “true” longitudinal plane without turning your wrist while fanning.  Staying “true” to the longitudinal plane will give you a good CVC image.

Likely a fail!

Note that the hand holding the probe is holding the probe like a pencil in A). By doing so, the scanning plane is like the piece of paper in B) and obliqued which will not give you a good image of the CVC .

A final comparative image!

Rocking cranially to get the caudal vena cava.


The image of from the 2nd edition of our textbook, a great resource for you, that may be purchased through Amazon.  Note in A) the probe marker is directed far cranially bringing the white line of the diaphragm close to the probe head, the near field, as shown in C).  In contrast in B) the probe is directed toward the spine, which will be a fail for imaging the CVC.

Note in C) and D) the CVC is expected a Texas longhorn away from the “cardiac bump”, where the heart is against the diaphragm.

Finding the CVC – 1) Texas Longhorn away, and 2) increasing depth to find and then follow the column of reverberation artifacts to the diaphragm.  

Finding the CVC Accurately – Quiz

Note the image to the left and then the arrows showing the possible location of the CVC.  Which image is correct (A-D)?  Answer at the bottom of the post.

Measuring the CVC Height

Measuring the maximum height (it’s not a diameter, there is no circle shown) and using our chart to categorize as fluid responsive (bounce), fluid starved (flat), and fluid intolerant (FAT).  The best manner to find the maximum height is to image the CVC over several seconds because it has respirophasic variation, then freeze and roll the track ball through frames finding its maximum height.  Although, the “eyeball characterization” of the CVC trumps the maximum height.

You may use B-mode or M-mode, however, B-mode is usually much easier (unless you are a cardiologist or use M-mode a lot).

Hepatic Venous Distension and the “Tree Trunk Sign”

We have shown and published (Chou et al. 2021) the “Tree Trunk Sign” as 96% specific for the presence of right-sided congestive heart failure (R-CHF).  In normalcy you do not expect to see hepatic venous branching.  This Chou et al. study is available open access and has some interesting, easily readable tables with measurements of the caudal vena cava and gallbladder.

Watch the Power of the DH Webinar for more information.

Click here for the LINK to the “Power of the DH View” Webinar from March 2022.

Quiz – Answer is D.

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