MRI scans are considered the gold standard in diagnostic imaging for musculoskeletal conditions with clinicians making many important treatment decisions based on their findings. With this in mind, how much trust should be placed in the findings of MRI scans? A recent study by Dougil, Reeves, Le Maitre, Andrews and Cooper attempted to answer the question – are MRI scans a good clinical tool to diagnose mechanical factors for low back pain?
Why is this important?
Low back pain is the leading cause of activity limitation and work absence throughout much of the world and around 60-70% of people will experience it at some stage in their life. When low back pain persists, people will usually see their GP or physiotherapist for treatment and/or advice about the best course of action. It is common for health professionals to then request some form of diagnostic imaging to assist with making clinical decisions, with MRI being the most trusted.
The recommended course of action is slowly changing to place less emphasis on imaging findings as we now know that the results of these scans often do not explain a patient’s symptoms or can show asymptomatic variants that may lead patients to believe that their condition is worse than it actually is.
One reason that MRI scans may not accurately show the cause of a patient’s pain is due to the position the scan is taken in. For many people their low back pain is only present while sitting or standing and can go away completely when lying down. As MRI scans are almost exclusively performed in a relaxed, lying position, the information we can get about how the structures of the spine function under load is quite limited.
Dougil and his colleagues found that the curve of the spine while standing, especially with added load, is significantly different to when lying flat. This obviously has implications for deciding whether a finding (or a non-finding) on an MRI scan is important and therefore whether further action – such as surgery – is required.
What’s the verdict?
MRI scans are a vital tool for assessing musculoskeletal conditions, but this article shows that when it comes to MRI scans of the lower back, there is a need to interpret the results with caution. It is true that concern about an incidental finding can lead to unneeded anxiety for the patient, but it also seems possible that a ‘clear’ scan that is taken while lying flat does not necessarily mean that there won’t be structural issues when the spine is under load.
As always, careful consideration of clinical signs and symptoms along with diagnostic imaging results is the best way to go.