Well Xue,
I have never seen this before !
But I guess we don’t actually scan the costal cartilage with much detail very often.
It is really common to see calcifications in the costal cartilage as a normal variation, however this is not what you have found.
I agree it is some sort of fluid moving within the costal cartilage,
I don’t agree there is any gas within the fluid.
I think the echogenic material is more consistent with some debris within the fluid rather than gas as gas has a fairly characteristic appearance on ultrasound which I think is absent here.
As you scan through on the video clip I feel like there is some calcification in the costal cartilage and a thin area of unossified costal cartilage where you are observing this appearance.
Could you see it in the shore axis of the rib to show the movement was within the costal cartilage and not between them?
I have considered an artefact, however I don’t think I can explain it as an artefact and the movement of the debris within the fluid is consistent and looks real.
My hypothesis would be that the cartilaginous component of the costal cartilage has some fluid tracks within it as a developmental feature and that there is debris formed within that fluid which moves as a result of pressure and postural movement of the costal cartilage when the patient breathes.
This is purely a hypothesis!!!
I would love to ask a thoracic surgeon of the costal cartilage can naturally contain pockets of gelatinous material or fluid within the structure of the costal cartilage. If the answer is yes, this is what you are observing.
If the answer is no, and costal cartilage are ALWAYS solid blocks of dense cartilage then I have no idea!
I can’t explain it as a pathological condition and I don’t think it represents any lung pathology so I am not surprised the CT was normal.
What about an MRI of the chest Xue, not on this patient but in general. Do you ever see areas of high signal indicating liquid pockets in the cartilaginous costal cartilage?
This is a great observation by you Xue and I will be fascinated to get to the bottom of it.
If anyone else has seen this or has any alternative hypothesis please add to the post.
Great case Xue,
Let us know your ongoing thoughts,
Steve.