Your vet can get a lot of information about what might be wrong with your cat from talking to you and examining your pet. Sometimes your vet may need to take a blood sample to test for diseases. X-ray and ultrasound allow your vet to look at the organs and bones inside your pet’s body without having to perform an operation.
X-rays are like light except they can travel through the body. For an x-ray your dog will lie under the x-ray machine which sends a beam of x-rays through your dog’s body onto a photographic plate (like a piece of film). When the plate is developed your vet will have a picture of the inside of your pet. This is called a radiograph.
Veterinary ultrasound machines are just like the ones used by human doctors to scan babies in the womb. As its name suggests, ultrasound is a form of sound. Just as sound waves can pass through solid objects (like doors and walls when your neighbour has a party!), ultrasound can pass through the skin into your cat’s body.
The sound waves are directed through the area your vet wants to look at and some of them are reflected back like an echo. These echoes are detected by a special computer that uses them to produce a map of the inside of your pet that your vet can read.
No, it is not possible to feel x-rays or ultrasound. For ultrasound examinations, fur will need to be shaved over the area where your vet is taking the picture. The ultrasound machine must be in contact with skin to let the sound waves get into the body. The hair should grow back quickly after the examination.
Taking an x-ray is a bit like taking a photograph of the inside of your cat. For x-ray examinations it is important that your cat lies still as the exposure is made or the final picture will be blurred. Nurses and vets take many x-rays every day and so they cannot hold all the patients or they would also be exposed to the x-rays which can be dangerous over a long period of time.
Ultrasound examinations can take up to an hour to perform. Although your pet can be held by a nurse while the vet performs the examination, many cats do not like to be held still for this length of time. Giving them a sedative makes them relax so that they are not worried by the examination.
X-rays, when used to produce pictures of your pet, will not cause side effects. Exposure to high doses, or over long periods of time, can be dangerous and this is why your vet cannot hold your cat for the examination.
There is no evidence that ultrasound examinations carry any risk at all.
The risk associated with the tests is that of upsetting a sick cat or one with breathing difficulties by struggling with it, or the risk of the anaesthetic or sedation in an ill animal. Your vet will explain the risks to you and if you are in any doubt about the risks please ask your vet to explain why they need to do the tests. In almost all cases the risk of not finding out what is wrong with your pet (and therefore not being able to treat it) is far worse than the risk of the anaesthetic.
Although your vet will be able to get the pictures from these examinations on the same day, they may want to send them to a specialist for a second opinion before giving you a final diagnosis. Some vets specialise only in reading x-rays and ultrasounds and may be less likely to miss some information on the pictures. Some veterinary practices now have a specialist in the practice or one who visits the practice regularly to perform these examinations.
Your vet will be happy to explain to you why they need to do tests on your pet. If you do not understand the reasons please ask someone to explain the tests to you. If you are interested, your vet will probably be able to show you the pictures of your pet after the examination and explain what they can see.