Are you sure I don’t need an MRI scan?

by Rosi Sexton

Patients are sometimes concerned that their doctor hasn’t sent them for an x-ray or MRI scan of their injury, and often their perception is that they’re being short changed, or that the decision is just about saving money. But there’s usually more to it than that.

I often explain to people that we only need a scan if the answer might change what we’re going to do. That sounds like it should be common sense, but it’s the kind of common sense that can all too easily be overlooked.

Sometimes we might have a very good idea of what’s likely to be causing a problem, but we’d need a scan or x-ray in order to confirm it. In other cases, there may be more than one plausible diagnosis, but only a scan would be able to tell us the difference.

Why don’t we send our patient off to radiology to find out? Because very often, the answer doesn’t matter. In a lot of cases, we don’t need to be 100% sure exactly where the damage is in order to provide good advice and treatment. Whether the back pain is the result of a small injury to one of the discs or a ligament strain, we’re going to treat it in the same way based on the patient’s symptoms and our assessment of their progress. Whatever came back on the scan report, it would make very little difference to anything that we’re doing in clinic.

When I explain this to people, they sometimes want to pay to get a scan themselves “just for peace of mind”. I can understand that; the urge to know for sure what is going on can be a strong one. The trouble is, the results don’t always give the peace of mind that they’re looking for. What often happens instead is that the scan report comes back with a bunch of worrying sounding medical-ese terms on it (“lesions” this, and “degenerative” that, and “stenosis” the other). I’ve often had to sit with an anxious patient and explain to them that actually, their scan results are entirely normal. In the same way that we accumulate scars and wrinkles and grey hairs as we get older, our joints start to change in ways that may technically fall under the label “arthritis” (or euphemistically “wear and tear”), but are actually a normal part of the ageing process.

To make matters worse, quite often a scan will pick up something that might be the cause of the person’s pain – or it might not. We know that a large-ish proportion of people with no back pain at all will show signs of disc degeneration on an MRI scan. So when your MRI picks up signs of disc degeneration, what should we make of it? Is it the cause of the problem, or is it purely incidental? Research suggests that for many conditions there isn’t a straightforward correlation between MRI findings and pain (see for example, here), so even after an MRI, we still may not be certain what’s causing your problem.

When people find out that there’s something “wrong” on the scan, they tend to feel a whole lot worse than they did before. They often worry about moving around, or doing things that they were able to do with no problem prior to the scan, because of a natural concern that they might aggravate the problem, or wear through the cartilage, or pop that disc out even further. I can explain that that’s not how it works – but the subconscious mind is a funny thing. When I got my MRI results back on my neck, confirming that I had two prolapsed discs, I knew all this – and yet, I still found myself moving differently, being more careful and worrying about it in the gym. The problem is, movement and exercise are actually helpful for many of the conditions we’re working with; and fear of movement contributes to pain. Helping people rebuild their confidence to move is a big part of my job, and this is almost always harder when there are some ambiguous scan results playing on their minds.

One worst-case scenario that I’ve seen a few times is when something pops up on a scan, and the patient ends up having unnecessary surgery for something that wasn’t causing the problem in the first place. One of my patients had had a knee injury playing sport. She was given a scan, which picked up a meniscus (cartilage) tear, that was eventually operated on. I first saw her a couple of months after the operation, which had made no difference at all to her symptoms. A quick assessment revealed that her symptoms were never those of a meniscus tear in the first place; she had a different knee problem that was almost certainly unrelated. Within a few weeks of rehabilitation, her knee was much better. We’ll never know for sure, but it seems likely that she could have been spared the months of pain, time off from playing her sport, and the inconvenience of surgery.

Having said all this, let me emphasise: of course there are times when an x-ray or a scan is definitely the right move. If we have a clear idea of what we’re looking for, and getting the correct treatment depends on what the answer is, then we’re looking at an entirely different situation. When used appropriately, modern imaging technology can (quite literally) be a lifesaver; we just need to make sure we’re asking it the right questions, for the right reasons.