This is the month of halloween, and skeletons, goblins, and guts will make their annual appearance. In medicine, we tend to see bones and organs in a different way that this freaky holiday portrays however.
Since the skeleton and organs are on the inside of the body, we often require some means of diagnostic
imaging to see them. Diagnostic imaging can include a variety of tools-the most common being x-rays (radiographs) and ultrasound. Others include things such as CT scans, MRI scans, endoscopy (and it’s many branches), fluoroscopy, or PET scans.
Radiographs or x-rays are one of the most commonly used diagnostic imaging tools used. They take a two dimensional picture of an area of the body. They can see bones and metal as bright white, and gas or air as dark black, and fluid, fat, and other soft tissues as other shades of gray. It can reveal the outline of organs as well seeing some of the contents in the stomach or intestines. X-rays can be used to see if there is heart enlargement, fluid buildup, foreign body ingestions, tumors, fractures, bladder stones, or infections present. X-rays are not the best at seeing inside some of the other organs such as the liver, kidneys, spleen, or pancreas.
Radiograph of abdomen of a male dog.
Ultrasound is another common tool used to image the inside of a pet’s body. The ultrasound is a real time movie of the organ’s insides, and can show blood flow and movement. It has a hard time determining overall size of an organ, so x-rays are still often used to determine if a liver or heart for example are enlarged. An echocardiogram is an ultrasound of the heart, and can be used to see the values, wall thickness, and look for turbulent blood flow (murmurs). Abdominal ultrasounds are able to look inside the liver, gall bladder, spleen, kidneys, bladder and intestines. It can find small organs not visible on x-rays such as the adrenal glands, lymph nodes, and the pancreas. However, ultrasounds cannot see through gas, so it has a difficult time seeing all of the intestinal tract and stomach, and cannot be used well to look at the lungs.
Ultrasound of abdomen. Spleen across top, left kidney in the center of the photo.
Pets can undergo CT or MRI scans as well. They have to be anesthetized to have these performed, but these diagnostic tools give a better look inside the body. They can be used to look at the brain, spinal cord, look for pinched nerves/slipped discs or intervertebral disc disease and for this reason are useful in planning back surgeries. They can be used to look for tumors and tumor spread, and can often be used to plan surgical removal or or radiation treatment of certain types of cancer.
Another diagnostic imaging tool available is endoscopy. This involved using a camera scope to look inside certain organs such as the GI tract (endoscopy or colonoscopy), inside the airways (bronchoscopy), inside the nose (rhinoscopy), inside the ears (otoscopy) or inside the joints (arthroscopy). Small samples of tissues can often be taken when using a scope to help get a diagnosis. Sometimes removal of foreign material or tumors or polyps can also be performed with a scope.
Fluoroscopy is very similar to x-rays, but it is a live movie like x-ray. It is used for things that are dynamic, such as collapsing tracheas or swallow studies. This is only done at specialty clinics.
Lastly, some animals can have a PET scan done. PET scans are a specialized test where a radioactive medication is given, and images are taken to see where the medication travels in the body and where there is uptake. For instance, thyroid cancers tend to uptake radioactive iodine medications. This is a very specialized type of diagnostic imaging that is only used in certain cases and is performed by specialists.
Overall, with the variety of diagnostic imaging tools available in the medicine field, we are able to diagnose a variety of diseases, perform surgery or start medications to help manage, treat, or even cure these diseases, and to monitor progress. Through imaging, we are able to offer better medicine for our pets!