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To scan or not to scan?

Published: 29 Aug 2017

Are your scan results helpful or harmful?

One of the first questions I’m often asked from patients is ‘Do I need a scan for my injury?’. The answer to this question is dependent on many factors and cannot be answered before a thorough examination is done. I also see many patients who are distressed about their X-ray, CT, MRI or Ultrasound results. Most of the time this stress is unwarranted as scan reports are often full of medical jargon which describe relatively normal/age related findings. The question then is, when should a scan be ordered?

Pros

• Can be a great tool to rule in certain pathologies but just as importantly, to rule out sinister pathologies e.g. tumours (this is very rare!).
• Can tell us the severity of an injury and therefore influence further management. An x-ray for a severe ankle sprain can determine if there is a fracture, and if so a boot or cast may need to be applied.
• Scans can confirm clinical findings which may lead to surgery. An example is MRI for acute knee injuries.  If clinical tests susgest ACL rupture, MRI can confirm this and surgery/specialist review is likely to be required.
• Scans can help find sources of pain which can be hard to determine from clinical examination and tests.

Cons

• Some scans such as CT and X-ray do have radiation. While the dosages are low, radiation exposure is cumulative over a lifetime. Therefore these types of scans should not routinely ordered.
• Minor findings are of no value in helping to explain the majority of aches and pain. In fact, not only are they not helpful, studies suggest that they are even harmful from a psychological point of view especial when they tell the patient they have, disc diseases, arthritis and tendon tears.
• If you look, you will find! Scans will nearly always show ‘incidental findings’. These are findings which are not related to the current injury/symptoms and are quite common, however can sound awful and can lead to fear avoidance behaviours. Good examples of this are:
  • 98% of adults and seniors with no neck pain have evidence of degeneration in the cervical discs in their neck.
  • 85% of adults with no knee pain have knee arthritis on x-rays.

Lisfranc injury is an example of a condition that requires investigation to diagnose and manage appropriately.

When should I get a scan?

Scans in most circumstances scans are not needed in the first instance. A thorough clinical examination along with subjective history and mechanism of injury will help guide your physiotherapist. If the scan is not going to change the management then often they are not needed or can be done at a later stage if required. If you do need a scan it is important that your physiotherapist or doctor takes time to go through the results. It is important they explain what findings are normal and abnormal. Scans, when required and explained properly are very helpful however a lot of the time they over prescribed and poorly explained.

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