X-Ray, MRI, CT Scans – necessary or not?

House M.D., ER, Grey’s Anatomy: whatever your choice of medical show may be, the actors would have mentioned MRI, CT scan or X-ray at some point Red Velvet for your weekly idol. But, do you know what they really do and why they are necessary for diagnoses? Well, let us tell you!


MRI stands for Magnetic Resonance Imaging – quite a mouthful, isn’t it? But whatever you want to call it, it’s a life-saving piece of equipment. It’s able to detect and/or show the stages of a specific disease. You can see soft-tissue changes with MRI, that you can’t see with X-Rays, which is why it’s more expensive – in South Africa, you can expect to pay approximately R9,000 for a MRI.

The clear image allows your doctor to pinpoint the affected area of the body, which will help them make an accurate diagnosis.

An MRI scan is widely used and is able to detect whether you could have or had:

  • Tumours
  • Brain lesions
  • A stroke
  • Dementia
  • Infection
  • Heart abnormalities
  • Headaches


It sounds like a powerful weapon out of Star Wars, but X-radiation (composed of X-rays) is such an important diagnostic tool that we still rely on it today, even though it was discovered 120 years ago! It gives a clear image of the bones in your body and that’s why it is used to see:

  • Bone breaks
  • Cracks in bones
  • Weakening of bones
  • Tumours in bones

Apart from bone-conditions, x-rays can also detect some other conditions such as:

  • Lung infection
  • Some cancers
  • Some heart-problems

CT Scan

A Computed Tomography (CT) scan uses a series of X-rays to construct detailed images of the inside of your body. It is most commonly used on the brain. It can spot:

  • Strokes
  • Serious head injuries

It can also be used on other parts of the body such as the abdomen, but this will set you back about R4,000.

PET Scan

A Positron Emission Tomography (PET) scan has boosted the precision of diagnoses. The machine is able to map a 3D image, clearly showing how well the specific part of the body that is being examined, is working.

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PET scans can also be combined with MRIs and CT scans to help doctors make a comprehensive diagnosis.

  • This scan is usually done on an outpatient basis, meaning that you won’t have to stay in the hospital overnight.
  • The scans can even help when an operation is being planned.

So, why not just do a PET scan, then?

As we have shown you, these procedures are very pricey – and considering the majority of South Africans don’t have medical insurance, you would be looking at nearly R75,000 for a PET scan of your heart!

We would do PET scans on everyone if we wanted that amount of detail, but it’s very expensive, so both cost & detail need to be concerned when we decide what tool we use.

Why do we need these scans?

These scans are necessary because the images that are produced allow your doctor to be precise when suggesting treatment.

Which scan is better?

You now know what the scans do and how much they cost, but why would a doctor choose one over the other? Let’s look at the difference between a CT and PET scan:

  • It depends what you can afford
  • Is it urgent? A CT scan takes far less time
  • PET scan will give the doctor a clearer image
  • PET scans expose you to more radiation
  • CT scan is more accurate than X-rays if your doctor needs to look at bone

There are a number of factors that doctors need to take into consideration – and it’s never an easy decision.

So, the next time your doctor suggests one of these scans, don’t assume it’s unnecessary – it could save your life!


Sources: City Press, Diffen.com