X-ray of my cat shows strange rib shape

Question

I found a wild cat, which has a difficulty with breathing, it seems that her nose is blocked and a lot of saliva is coming out.

Beside that, we went to a vet to check this cat, blood test, temp., x-ray... so after taking x-ray we saw that her ribs have a strange shape. Local vet says that it seems that this cat suffered possible impact in that area, but he is not sure.

Her condition, beside difficulty of breathing is normal, she eats regularly, she drink water also she is happy and wants to play with me.

My question is; is it possible that x-ray is mistaken, because of a sudden movement?

Also second x-ray in different cat position shows different shape of ribs.

Can anyone explain, how can I interpret it?

Answer 1

The explanation of how the first X-ray can show severely dented ribs while the second does not is a combination of the movement of the cat and the way the X-ray machine takes a picture.

Since I had difficulties noticing where the ribs look dented, I marked them:

Most digital cameras work with a rolling shutter. They don't capture the whole picture at once but scan the image row by row from top to bottom. It works just like a document scanner but faster.

If the object being captured moves, the image gets distorted, like demonstrated with both rotors of this helicopter:

The cat probably startet moving as the X-ray machine was scanning the area around the heart, which distorted the image of the ribs there.

By the way, many (especially older) vets and doctors don't know about the rolling shutter effect because they studied at a time when there was only analogue X-ray. If the subject moves during analogue X-ray, the resulting image is blurry. If the subject moves during digital X-ray, the image looks sharp but distorted. There are high-end digital X-rays that capture the whole image at once with a global shutter, but the other ones are less expensive and therefore more common.

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That said, the vet should probably concentrate on what is blocking the nose of this cat than looking for proof of severe trauma to the ribs that just isn't there.