MRI and CT scans – Are we over-imaging?

The economic burden of LBP on the working class is tremendous. Most people can’t afford to be off work for one day, much less a week or even months. Have you ever taken some pain killers for your lower back pain (LBP) and hope it goes away? However, after a few days the pain remains so you decide to see your doctor. After an examination, your doctor refers you for an MRI or CT scan. Sound familiar?

Since the lower back bears approximately 2/3 of your body’s weight, you can usually find many abnormalities in an individual over 40 years old. In fact, it would be unusual to see things such as an absence of disc degeneration or spondylosis, disc bulges or herniations and joint arthritis. Approximately 67% of adults suffer from lower back pain at some time in their lives, with over 85% of people with LBP diagnosed with “non-specific low-back pain” suggesting that there are no underlying condition or diseases responsible for the pain.

MRI and CT scans can be misleading to individuals suffering from LBP. Being as the primary cause of LBP is functional not structural, this influences the individual into thinking whatever shows up on the MRI or CT scan must be the problem. Having all this information makes it difficult to determine which findings on the MRI or CT scan has clinical significance. In other words, where is the LBP originating from? Is it from disc degeneration, disc bulges or arthritis? In over 85% of LBP cases, the cause of the problem is in the muscle. The bones, disc and nerves in the spine are protected by load bearing musculature which carries 70% of the load of your body. When the musculature is unable to support the lumbar spine, bones are forced to take additional load and pressure – this is where problems can occur. MRI and CT scans show limited insight into muscle functionality and strength. The majority of LBP comes from musculoskeletal disorder, which are treatable through medication and exercise rehabilitation.

A review by J. Breslau and D. Seidenwurm examined studies of MRI and CT scans in individuals with and without lower back problems to look at how useful these scans are in prediction the presence of LBP.

Study 1

  • 35% of those who did not recall ever having back pain were found to have abnormalities including disc herniations in their scans.

Study 2

MRI scans found that of 67 individuals who did have back pain:

  • 20% of those <60 years old had disc herniations and 36% of those >60 years old had disc herniations.

Study 3

98 people without symptoms of back pain:

  • 36% had ‘normal’ lumbar MRI
  • 28% had disc herniations

Study 4

MRI scans of people without back pain:

  • 56% had annular tear
  • 33% had disc protrusions

 

As MRI and CT scans have the ability to show spinal abnormalities, but these abnormalities do not necessarily indicate the increased likelihood of LBP. MRI and CT scans have not shown to have positive impact on a patient’s treatment. Patients can become falsely labelled as having serious back problems and this can encourage disability and self-limiting behaviours. For example, an individual with LBP may think disc bulge or degeneration in their scans is the main cause of their pain, therefore assume they have a permanent or serious condition. MRI and CT scans do not assist in defining the nature of back problem for most individuals with LBP. If you do undergo scans, be sure to discuss the findings with your allied health professional. For most individuals, the scan findings should not stop you to manage your LBP and continue with normal activities of daily living.

Daniel Nguyen (B.Sc. Exercise Physiology)

Accredited Exercise Physiologist (AES, AEP)(ESSAM)

 

Reference

  1. Breslau and D. Seidenwurm (2000). Socioeconomic aspects of spinal imaging: impact of radiological diagnosis on lumbar spine-related disability. Topics in Magnetic Resonance Imaging 11(4): 218-23.
  2. Brinjikji, P.H. Luetmer, B. Comstock, B.W. Bresnahan, L.E. Chen, R.A. Deyo, S. Halabi, J.A. Turner, A.L. Avins, K. James, J.T. Wald, D.F. Kallmes, and J.G. Jarvik. Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. AJNR Am J Neuroradiol 2014 Nov 27

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