HOW TO UNDERSTAND AND INTERPRET YOUR MRI SCAN: LOW BACK PAIN

Understanding and interpreting your MRI

Interpreting your MRI is not as easy as it seems. A common (mis-)understanding is that what you see on the picture correlates well with the pain that you feel. This comes from the underlying theory that pain and tissue damage are one in the same. But the truth is that this is an outdated theory that no longer holds up in the evidence. An MRI is merely a picture. A picture cannot depict pain. Therefore, your MRI alone can’t say much, if anything at all, about the pain that you are experiencing. Pain is something that you, the individual, experiences, and not something that we see in a picture.

Pain is something that you, the individual, experiences, and not something that we see in a picture.

So what does an MRI show then?

Indeed an MRI shows the state of your tissues. However, these scans are only a representation of a moment in time and not necessarily a very accurate representation at that. An MRI only shows what your tissues look like on that particular day at that particular hour that you have had your scan taken. Most of the time, MRI scans are a one-off thing, made during a period of time when you are also experiencing pain. Since we usually don’t have a previous MRI scan, from a time when you were not experiencing pain, or even just from an earlier time, it is difficult to know if what we see now on a scan is reflective of your current state of pain. Perhaps, this was always the state of your tissues, but now, you also feel pain.

As well, we have to acknowledge that the result of an MRI is not only the picture itself, but also the interpretation of the picture, which is made by the radiologist. After the scan is taken, depending on where your MRI is done, the radiologist from that centre will then make an interpretation of the picture and report that interpretation as part of the findings. However, what we see in research is that there is high variability in what is reported depending on the radiologist making the interpretation. A study done by Herzog et al., showed that one patient who had 10 MRI scans taken at 10 different MRI centres over a period of 3 weeks had 49 different findings, none of which were unanimously reported in all 10 scans. Although this study may not be reflective of all MRI findings, it is important to remember that it is after all an interpretation and those interpretations are open to human error.

Scans and Pain

So let’s dig a bit deeper into this concept of the state of the tissues and pain. It is common to think that if we see something on a scan then we can know for sure what the source of our pain is, but unfortunately, it’s not always as clear cut as that.

It is common to think that if we see something on a scan then we can know for sure what the source of our pain is, but unfortunately, it’s not always as clear cut as that.

An MRI is just one piece of the whole picture, the same way that looking at a picture of your bicep doesn't tell us anything about how strong it is, how much it can lift or how it might feel doing so.

The reality is that pain is a complex experience that is affected by many factors including; emotions, beliefs, cognitions, past experiences/memories, rest, nutrition, stress, health, overall well-being, AND the state of your tissues.

Definition of Pain:

The official updated (2020) definition of pain from the International Association for the Study of Pain (IASP) is as follows:

“an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”.

Since pain is understood as a sensory and emotional experience, pain cannot only be related to the state of the tissues. In fact, it’s never really that safe to say that only one thing is the cause of your pain. There are potentially many factors that contribute to your pain experience and although it’s possible that what you see on you MRI may be contributing to your pain, it is most likely not contributing as much as you might think [2].

When pain and damage don’t match:

First of all I think it’s good if we address the difference between the terms “damage” and “structural changes”, because they are not one in the same. There is a lot of confusion about this in the world of scans and it leads to a lot of unhealthy ideas about what is normal and abnormal to see on a scan. Although damage does change structure, structural changes are not equal to damage.

Refer to this table below:

In this research they scanned the backs of asymptomatic people, meaning people who were not experiencing any pain (in this case low back pain) and the findings are quite interesting.

You can see in this table an overview of the findings seen on the scans of patients across the age categories from years 20 up to 80 + years. Take a look for example in the category of disc bulge. Notice, how even in the age group of 20-30 years old, you can see that up to 30% the scanned individuals show the finding of a disc bulge, yet experience no pain. Notice how that number only increases with age.

So you see, no matter what age you are there is always some percentage of the population that will be having these kinds of structural changes or what have been previously been called “abnormalities” yet do not experience any pain. But, when we really take a good look at these numbers, it becomes clear, that these may not actually be abnormalities after all, but just a normal representation of age-related structural changes. And we see these structural changes in asymptomatic populations over and over again in studies, not just for back pain, but other areas of the body as well. These age-related structural changes can be seen as just normal signs of ageing, like “wrinkles on the inside” as some have put it.

So you see, no matter what age you are there is always some percentage of the population that will be having these kinds of structural changes or what have been previously been called “abnormalities” yet do not experience any pain.

As we grow older, we may have more wrinkles on our skin or our muscles might lose some capacity to be strong or grow big, but that doesn’t mean that we’re destined to live a weak life and to wither away. Our bodies are living, breathing, organisms that will adapt to whatever the situation. This is why we see some people still thriving in their 90s, performing lots of physical activity and why some people become more and more immobile at much younger ages for a variety of reasons. The organism still has to potential to change and adapt as we age, just to a slightly lesser degree.

Do the state of my tissues play a role at all in my back pain?

Yes...AND no!

Probably not the answer you were looking for. But let me explain.

We have to be very careful that we do not confuse the issue of pain with the state of the tissues, because they simply do not correlate well, especially as time passes and pain persists [4]. If this were true, than we would see a lot more success in surgeries and procedures trying to treat persistent pain. But the truth is that most operations/procedures for persistent pain are unsuccessful and can actually lead to more disability [8,19]. Perhaps this is because these types of treatment ONLY treat the tissues and don’t address others factors that play a role in the pain experience. And if your pain experience and the state of the tissues are not well correlated than this makes perfect sense. The difficult part is that our medical systems (at least in the western world) still operate quite heavily on the assumption that they are.

We can’t change structure, but we can probably change pain.

There is some research to show that the MRI scans of people with back pain do seem to show more structural changes than those without [11]. However, it’s important to remember that what you see on a scan is not a prediction of future pain or future changes to your structures. In fact there is lots we can do to make the structures function better that have nothing to do with changing the actual form of the structures itself. For example, movement is very helpful for bringing fluid/lubricant in between joints, to help them move more easily. Changes to the amount of load we put through a joint, either more or less depending on what we can handle now can gradually be increased over time and increase the overall tolerance of the joints to movement. Decreasing our fear of movement due to unhelpful ideas that movement causes damage or that pain is only going to get worse, can also have a big impact. If we have inflammation in joints then perhaps that pain can be modified through physiological processes that help promote recovery, like resting, decreasing stress-related factors, decreasing weight or increasing cardiovascular training for example. It would be more accurate to consider whatever structural changes we see on a scan as more of a potential precursor to pain than anything more than that. And by no means the one piece of the puzzle that matters the most.

It’s important to remember that what you see on a scan is not a prediction of future pain or future changes to your structures.

Just remember:

Tissue state does not dictate pain and pain does not equal damage!

Thank you for reading!

If you would like to read the previous blog to learn more about

MRI scans click here: What an MRI is and who it’s for

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References:

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