Why your MRI report is not your diagnosis

The sentence that causes the trouble

Almost every spine MRI report contains a phrase like degenerative disc disease, disc bulge, facet arthropathy or foraminal narrowing. Read cold, those words sound like a diagnosis, a prognosis and an argument for surgery all at once.

They are none of those things. They are a description of what the scanner saw. Whether any of it is the reason you hurt is a separate question, and it is not one an MRI can answer on its own.

Wear is nearly universal, and often silent

Discs lose water content and height with age, the outer ring develops small tears, and load transfers to the joints behind. This happens to almost everyone. It is visible on the imaging of a great many people who have never had back pain in their lives.

That is the crux of the problem. If a finding is present in most people regardless of symptoms, then finding it in you tells you very little about why you are in pain. The term "degenerative disc disease" is particularly unhelpful here: it sounds like a progressive illness and is better understood as a description of normal change.

The same logic applies to a disc bulge. It is a common finding. It becomes clinically interesting only when it sits where it would compress something, and when what it would compress matches what you actually feel.

What makes a finding meaningful

Three things have to line up before an imaging finding is worth acting on:

• The finding is in a place that could produce your symptoms
• Your examination shows what that finding would predict — the right reflex, the right area of numbness, the right weak muscle
• The story fits: how it started, what makes it worse, what it stops you doing

The examination is what does most of this work. Testing power, reflexes and sensation maps which nerve is involved, and that map is then compared against the scan. A finding that does not match the examination is usually not the cause of the pain.

Where the two disagree, the examination generally wins. It is a test of how the nerve is behaving; the MRI is a photograph of where it lives.

This is why the order matters

A reasonable sequence runs: history, examination, and then imaging to confirm or refute what those two suggested.

Running it the other way round — scan first, then look for a problem to attach to it — is how people end up being treated for findings that were never causing anything. It is also why getting a new MRI before anyone has examined you often adds cost without adding information. Bring the imaging you already have.

Plain X-rays are sometimes more useful than people expect, because they are taken standing up. They show alignment under load, and flexion and extension views show whether a segment moves abnormally — neither of which a supine MRI can demonstrate.

For some back pain, a diagnostic injection is more informative than any scan, because it tests the hypothesis directly: numb the suspected structure and see whether the pain goes away.

The findings that do change things

None of this means imaging does not matter. A small number of findings genuinely change the urgency, and they are the reason a careful look is still worth having:

• Compression of the spinal cord itself, rather than a single nerve root
• Nerve compression with weakness that is getting worse rather than holding steady
• Fracture, infection, or a lesion that should not be there
• Instability — a segment that moves when it should not

These are uncommon. They are also the ones where waiting has a real cost, which is why the small print of a report deserves a clinician's reading rather than a search engine's.

What to do with the report you already have

Read it, by all means. Then put it next to these questions rather than treating it as a verdict.

Does anything in it correspond to where your symptoms actually are? Has anyone examined you since it was taken? Has anyone explained which specific finding they believe is responsible, and why that one rather than the others on the list?

If a procedure is being recommended, the thing to ask is not "what does my MRI show" but "which finding do you think is causing this, and what makes you confident it is that one". A good answer to that is worth more than the report.