To Scan or Not to Scan? That is the Question.

Should I get a scan? This is a common question we hear at Physiotas.  And it’s a question that doesn’t always have a simple answer.  To understand why clinicians would or wouldn’t recommend getting scans/investigations/imaging, we need to look a bit deeper at the research and information available.

Firstly, what is medical imaging?

Medical imaging (or a scan) is the technique and process of creating visual representations of the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of organs or tissues.  Simply put, it’s creating a picture of the body – both inside and out – to help diagnose and treat disease/injuries.

Unfortunately, it’s not as simple as just using a camera and taking a photo of the body.  We have skin/bones/hair/muscle/fat that gets in the way of the deeper tissue we may need to see.  So, science has developed a variety of ways to get around this – medical imaging!  It’s a broad term that covers everything from your standard X-ray, right through to things such as a colonoscopy and nuclear bone scans.  To make things simpler, we’ll look at some of the most common scans seen here at Physiotas.  Remember, below are very simplified explanations!

  • X-ray (or XR):  This is the most common medical imaging technique we see at Physiotas, and the one many of us have had at some stage.  Basically, an x-ray (radiation) source is projected through the body to create a two-dimensional (flat) picture of the body.  Because it is a flat picture, it is common to have a few (or a series) of images taken from different angles to get more information.  A typical XR is good at showing up bony structures, but often poor at showing soft tissue.
  • Computerised Tomography (a CT or ‘CAT’ scan):  These scans use a powerful computer to combine many x-ray measurements into one more detailed image.  They tend to show a cross-sectional image (slices) of the body part in question – although some CT’s are now combined to generate a 3D image.  CT’s are much better at showing soft tissue than a standard XR, as well as still being great at showing bony structures.
  • Ultrasound (or Ultrasonography): This is the use of ultrasound waves (sound waves much higher than the human ear can hear) to create an image of a body structure – typically tendons, muscles, joints, blood vessels and organs.  The sound waves create an echo which a computer then processes to create an image in real time. The example most people have seen of this is an obstetric (pregnancy) ultrasound of the unborn baby.
  • Magnetic Resonance Imaging (MRI):  These scans use a strong magnetic field to excite (affect) hydrogen atoms in water and fat within the body. This creates a detectable signal that is computer processed to create a detailed image.  MRI’s tend to be very good at showing most tissues in the body.

Ok, then which scan is best?

Well, it depends. All of the above (and the many more) diagnostic scans have their strengths (such as what they show, how clear the picture is etc) and weaknesses (cost, time, restrictions, error factors etc).  Basically, no one scan is the best. They are each good in different ways.  Each scan will show different information which can be used to create a different picture of the body to help diagnose and treat disease/injuries.

So, it should be pretty simple right? Getting a scan will diagnose what’s wrong with me? Why I’m in pain? Where do I book in?

Unfortunately, it’s not that simple.

More often than not, we seem to be explaining to clients why getting a scan isn’tactually the best thing for managing their injury or pain.

Before we look at why a client potentially shouldget a scan, we must first consider why maybe they shouldn’t.

The main reason why we, as physiotherapists, don’t refer everyone to get some form of scan comes down to one question – ‘is it going to change anything’? Is getting an x-ray going to change the management of a 70 year old gentleman who spent all day in the garden pulling weeds and developed a sore back over the weekend? No, probably not. Is getting an ultrasound going to change the management of a 35 year old lady who suffered a minor calf strain playing mid-week netball last week? Again the answer is no.  These are what we would call ‘unnecessary scans’ – those that aren’t actually required for the diagnosis or ongoing management of an injury or pain.

The other issue that arises when talking about medical imaging (particularly for musculoskeletal – ie bone, muscle, ligament, tendon or joint – injuries/pain) is that scans do not show pain.  They do not show the many biological, psychological, social, functional, situational factors that influence pain.  This means that someone who is in a lot of pain may have ‘normal’ scans, and someone in no pain may have lots of ‘issues’ reported.  A good example of this is the image below which highlights some research on just how many ‘normal’ people – with no pain or injury – have ‘pathology’ (something wrong) on scans.

And finally, we need to look at the cost.  Medical imaging is expensive.  An MRI in Tasmania, for instance, is typically around $300-500.  Other scans may seem cheap to use, as they are covered by Medicare, but the money still needs to come from somewhere – in this case our tax dollars.  Now, no physio would recommend a client who clinicallyneeded to get a scan to avoid this to save the government money. No, the issue is the unnecessary medical imaging performed daily.  These are the scans done “just in case”, “just because”, “haven’t had one in awhile” or “because I want to know”.  In the US, studies show between 7.5 and 12 Billion dollars are wasted on unnecessary medical imaging each year.  There is no figure for the cost of unnecessary medical imaging in Australia, but the Australian Medical Association (AMA) has highlighted this issue in their latest position statement on medical imaging.

So, now that we have looked at why getting a scan may not be the best thing for a client, we need to consider when it is appropriate to refer for medical imaging.

Thankfully, we (the whole medical and allied health field) have a thing called “Diagnostic Imaging Pathways” or ‘Clinical Rules’ to help us.  Basically, these are ‘guidelines’ that have been developed by groups of specialists from around the world, looking at all of the available research to clearly say when medical imaging is required and, if so, what test(s) should be done.  For instance, if you sprain your ankle and you don’t meet certain criteria (pain in certain locations, being unable to take 4 steps) an x-ray is not indicated. These guidelines help determine if, when and what medical imaging should be done.

Essentially, the reasons that we would refer for medical imaging fall under two broad categories:

  1. To guide management options.
  2. To rule out ‘nasties’ – which could be anything from fractures to more serious (and rare) conditions such as cancer.

Using the ankle sprain example above, if you had pain over the navicular (one of the midfoot bones) and weren’t able to take a few steps, it is likely you would be referred for an x-ray.  If this showed a fracture, then the x-ray would help determine the management options (plaster cast, brace, surgery etc).

So, should I get that scan or not?

The simplest answer is this – a blog post can’t tell you that.  No blog post could ever hope to provide an answer that takes into account the many complex biological, psychological, social, functional, situational factors that exist with any clients injury or pain.

This is where your physiotherapist comes in.  As physiotherapists, we are able to use our clinical reasoning (the cumulation of our years of ongoing study and experience) to help guide you whether you should get a scan or not.  And, if so, what scan is going to be most approprate for your situation. We can speak with GP’s, specialists and other health professionals to help organise medical imaging (if appropriate) and develop an appropriate management plan for your pain or injury.

So, to scan or not to scan? That is the question……

About the Author:

Daniel Yeo is a Physiotherapist at Physiotas on the North West Coast.

Dan has been working at Physiotas since graduating from Monash University with Honours in 2011.  He has undertaken further professional development in the acute management and rehabilitation of sporting and spinal injuries, as well as dry needling and Clinical Pilates. Dan is involved in the Clinical Pilates and Workplace Health programs at Physiotas.

Dan has worked with a variety of local and interstate sporting clubs including Devonport FC, Tassie Mariners and Soccer TAS.  His professional interests include Clinical Pilates, sports and spinal injuries, post-operative rehabilitation, dry needling.

In his spare time Dan enjoys working with sporting teams, running, hiking, and playing tennis and hockey.