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MRI's: When DO I need one?

Pain and imaging (MRI's, X-Rays, etc.) is, and probably always will be, a bit of a contentious issue. As knew and more accurate tests and scans become available, naturally it's felt that if you want to know what might be causing your symptoms that imaging is the best course of action.

When it comes to pain, I've spoken before here about how pain and what is found on scans often doesn't match-up and that we try and avoid imaging where we can.

But when should you have a scan? Let's take a look.

Looking on the Inside

When we talk about imaging, a lot of the discussion centres around the spine. This is not really that surprising given the spine is one of the more complex areas of the body, one of the most common for experiencing pain(1) and one of the areas which generates the most fear about severity of damage and ongoing disability(2).

As a general rule, it is recommended that imaging is not done on the lumbar spine during the first 6 weeks of the onset of back pain(3). This is because the majority of acute onsets of lower back pain tend to resolve over that time, even if you are experiencing radicular symptoms (referred pain into the legs or mild sensory changes, often called sciatic pain), or there is a disc bulge present. From a physiotherapy point of view, if you present with lower back pain with or without leg symptoms, whether or not a disc bulge has been diagnosed wouldn't necessarily change our management. We'd still be looking at your symptoms and managing according to those. So why put you through unnecessary imaging?

What are the exceptions?

That being said, there are times when scans or imaging would be ordered. These are known as Red Flags and are the signs and symptoms that we as clinicians look for that tell us that imaging may be important to check for more serious issues. These would include:

  • Radicular symptoms (referred into the limbs) which have been present for more than 6 weeks and are severe enough that surgical intervention might be considered;

  • neurological deficits (such as changes to bladder or bowel function, significant numbness around the groin area or changes in your reflexes) which are severe or progressively worsening;

  • Sudden back pain with significant spinal tenderness (especially with history of osteoporosis, cancer, steroid use);

  • Trauma (eg. fall from a height, car accident or significant trauma followed by associated pain);

  • Serious underlying medical condition (e.g., cancer).

If any of these are present, then the person assessing you might make the call that ordering a scan to investigate further is warranted.

But what if I can just feel that something isn't right?

It's fairly common that people tend to be worried by their pain, particularly in the early stages when it can be quite severe. There's that little thought in that back of your mind that maybe something sinister is going on and that an MRI or scan would show you exactly what is happening.

That's understandable. It happens to the best of us.

Just have a read of this article, written by Adam Meakins, a physio from the UK. We are all human.

In that instance it actually shows how you can have pain without any observable tissue damage whatsoever. However, the main issue with what we are talking about is that MRI's will show things, often things of little relevance. We know that patients with no back pain often have abnormal findings on imaging(4), so it's likely that something will be found if you have a scan early on in your episode of back pain. Whether what is found actually has anything to do with your pain is completely different.

What's the harm you might say?

Well for apart from unnecessary radiation exposure from things like X-Rays, as well as the cost, it often ends up with you receiving a label which may or may not be relevant (such as having a bulging disc)(5), which has often shown to actually worsen outcomes and your sense of well-being(6). So this can have a negative effect on your recovery, and can actually lead to an increase chance of ended up having surgery(7, 8).

We know from numerous studies that damage does not equal pain. One study showed that 52 percent of the people they performed MRI on (all of which had no pain) had disc bulges at at least one level, and 27 percent of those had a disc protrusion(4). No symptoms. I've previously brought up the table below, which shows spinal abnormalities in people with no pain:

Brinjikji et al, 2015, Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations, American Journal of Neuroradiology 36:811(9)

So finding any of these results on a scan may be relevant, or they may mean very little when we look at then in the context of how you are presenting. We would then need to perform clinical tests (as part of a physical assessment) based on your signs and symptoms. It's only when the findings of the MRI are compared with the clinical tests conducted that you can determine whether they are relevant.

There are similar results for shoulders as well, with a high prevalence of rotator cuff tears in people with no pain(10, 11). If you do have imaging done on a painful area of your body, make sure to take all this into account. Ask questions and have the results explained to you so you can better understand it.

"It's only when the findings of the MRI are compared with the clinical tests that you can determine whether they are relevant."

So that's the crux of it. Often your health professional, whoever they may be, will not recommend (or even actively recommend against) having imaging performed. Usually this isn't because they don't appreciate the severity of your pain, but it's because they are looking for a number of other criteria that are not specifically pain related which will tell them the best course of action.

And in the end, no matter what your presentation (be it lower back, neck, shoulder, knee or any other body part), usually the number one reason someone will order imaging is if the information likely obtained from that scan is going to change the treatment or management you are going to receive.


  1. Hoy, D, Bain, C, Williams, C, March, L, Brooks, P, Blyth, F, Woolf, A, Vos T, and Buchbinder, R, 2012, A systematic review of the global prevalence of low back pain, Arthritis and Rheumatology, Vol: 64, Iss: 6, pp. 2028–2037;

  2. Al-Obaidi, SM, Nelson, RM, Al-Awadhi, S, and Al-Shuwaie, N, 2000, The Role of Anticipation and Fear of Pain in the Persistence of Avoidance Behavior in Patients With Chronic Low Back Pain, SPINE, Vol 25, Num 9, pp 1126–1131;

  3. Bigos S, Bowyer O, Braen G, et al, 1994, Acute Low Back Problems in Adults. Clinical Practice Guideline No. 14. AHCPR Publication No. 95-0642. Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services, December 1994;

  4. Jensen MC, Brant-Zawadzki MN, Obuchowski N, et al, 1994 Magnetic resonance imaging of the lumbar spine in people without back pain, NEJM. 1994:331;69-73.

  5. Shubha SV, Deyo RA, Berger ZD, 2012, Application of “less is More” to Low Back Pain, Arch Intern Med 2012;172(13):1016-1020.

  6. Modic MT, Obuchowski NS, Ross JS et al, 2005, Acute low back pain and radiculopathy: MR imaging findings and their prognostic role and effect on outcome, Radiology 2005;237 (2):597-604

  7. Webster BS, Cifuentes M, 2010, Relationship of early magnetic resonance imaging for work-related acute low back pain with disability and medical utilization outcomes. J Occup Environ Med. 2010;52:900-907.

  8. Jarvik JG, Hollingworth W, Martin B, et al, 2003, Rapid magnetic resonance imaging vs radiographs for patients with low back pain: a randomized controlled trial. JAMA. 2003;289;2810-2818

  9. Brinjikji et al, 2015, Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations, American Journal of Neuroradiology 36:811

  10. Connor, PM, et al, 2003, Magnetic resonance imaging of the asymptomatic shoulder of overhead athletes: a 5-year follow-up study, Am J Sports Med. 2003 Sep-Oct;31(5):724-7;

  11. Girish, G, et al, 2011, Ultrasound of the shoulder: asymptomatic findings in men, AJR Am J Roentgenol. 2011 Oct;197(4):W713-9.

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