Demystifying acronyms, a letter at a time

medical scans tell doctors stuff

Reading Time: 4 minutes

by Joni

Are you confused when your doctor sends you for a CAT, MRI, PET scan? Join the club. What is it? Should we have one if we don’t even know what it is? maybe not. So, let’s get a bit more informed about these medical tests and scans. Let’s demystify medical acronyms, a letter at a time.

Believe me when you get older you will be having scans all the time. They will start to interfere with your coffee dates. Since I have had CRPS, my local radiology people know me well and I’m getting familiar with the medical acronyms.

These amazing medical scans and procedures rely on artificially generated sources of waves or electrons. They are a testament to the intelligence of humans. We manipulate nature to our benefit like no other animal. Admittedly to the detriment of ourselves and other animals but that is so-called progress.

It began with X-Rays

Once upon a time X rays were at the forefront of medical diagnosis. These small wavelength penetrating waves pass through the body and are detected on a photographic plate. this process is called radiography and is good to see bone but not soft tissues. X rays are not definitive enough to distinguish detail around the upper body as the ribs and lungs overlap.

A CAT scan is a newer and more sensitive procedure that uses X rays. The letters of the acronym stand for Computerised Axial Tomography. No wonder they shorten it to CAT. These scans use X rays and fan them out as a rotating beam over the patient’s body. The detector rotates too and takes digital images in slices of the body.

These sliced images are collated to give a picture in grey scale that can highlight cancerous cells, blood vessel blockages and the grey and white matter of the brain. In this scan the ribs are digitally removed allowing a good view of lung tissue. A CAT scan takes longer than an X ray which is instant.

After CAT comes the PET

Cats and pets, it’s all very veterinary yet it’s not. A PET scan is even more complicated than a CAT scan. But it’s very useful for diagnosis. The medical acronym PET stands for Positron Emission Tomography. A positron is a positive electron produced by a radioisotope and for you not-into-science people, an isotope is an atom with an extra neutron in its nucleus. If this stuff is of interest, read about amazing Marie Curie who accidentally discovered radioisotopes.

The PET scan takes a while so be prepared for a morning out. But you can have coffee after and tell everyone about your experience. The first step is taking a radioisotope. Don’t panic! These are special ones that have very short lived and will soon disappear and do you no harm.

This radioisotrope releases positrons once in your body and these react with the electrons in your body as opposite charges attract. The result of this is a small production of gamma rays. These are detected by two detectors at 180 to each other. Then the computer takes over and makes sense of it all.

What do the doctors learn from a PET scan?

With a PET scan, medical experts can see tumours and evidence of strokes, measure blood brain flow and diagnose medical sclerosis or MS, epilepsy, Parkinson’s disease and schizophrenia. It is a very expensive procedure so not all hospitals can do these scans as the scanner is very costly.

MRI, Magnetic Resonance Imaging

Then there is the queen of diagnostic tools, the MRI scan. This medical acronym stands for Magnetic Resonance Imaging. It is a non-invasive technique that uses strong magnetic fields and radiofrequencies. It can be claustrophobic as the patient has to lie still while going into and remaining in a small tunnel. The tunnel generates the magnetic field that makes all the nuclei in our tissues to line up.

Then radio waves are emitted that may or may not resonate or match the frequency of your nuclei. Then the radio wave emitter is turned off and your nuclei relax to how they were originally but in doing so they emit the energy of their lining up. This energy is detected and made sense of by a computer.

MRI sees so much.

Different energies mean different types of tissue. The MRI scan can differentiate between normal and diseased tissues. It is the number one choice for scanning the brain and central nervous systems. From the results doctor’s can confirm strokes, multiple sclerosis and infections in the brain, spine and joints. It is also useful to assess ligament damage and disc degeneration.

The MRI scan takes about 40 minutes but longer if you wriggle. They have to repeat it or abort it if you panic in the tunnel. This is about 2-3% of people first time around. It helps to just zone out and have happy thoughts. That worked for me after first panicky attempt. Escape with your imagination to another place.

Scans help doctors and help you

The MRI is a very expensive machine so again not in every hospital. At some stage all of us may need a scan or have to take a family member for one. So it is good to understand what is going on and what the letters of the medical acronym stand for. Consider yourself fortunate if you can access such science. Many disadvantaged and remote communities cannot even access X rays or ultrasounds for pre-natal scans.

Okay, it might feel invasive and impersonal, but it is the only way doctors can have a window into what is going on in your body. It is better than the old way of opening you up, risking complications, bleeding and infection. Better than having leeches put all over you too!

Photo by Owen Beard on Unsplash

Joni Scott is an Australian author with three published novels: Whispers through Time and The Last Hotel and Colour Comes to Tangles. Joni also co-hosts a women’s blog; and has her own website;

Leave a Reply


Enjoy this article? Please help spread the word :)

Follow by Email
Fb messenger
Verified by MonsterInsights