MRI to detect stress fracture?

Triathlon Forum
1

Can an MRI detect a stress fracture sooner than the 2 weeks or that it takes to show on an x-ray?

I’ve developed a pain similar to a shin splint only higher and more towards the back of the calf. After a 12 mile run I can’t put weight on it for 24 hours and walk with a limp for another 48 hours. This has been gradually getting worse for 2 weeks. Doctor requested an MRI after the xray was inconclusive. Should have the results tomorrow.

It started a week or so after a minor bike wreck so I think the MRI may be to verify no blood clots. Just curious if anyone has had experience with an MRI for sfx, usually it’s xray and bone scan.

Supposed to be racing IMFL next month, the timing stinks.

2

I believe MRI’s are for soft tissue injuries.

3

Yes, last year my doc requested an MRI to diagnose a sfx. It ended up being a stress reaction (kind of a precursor to a full blown stress fracture) so after spending a month with a boot I was back to running.

Even if you have a stress fracture, it is highly unlikely it will show up on an X-ray.

4

Thanks to insurance I went, X-ray, X-ray, CT-Scan, X-ray, Bone Scan. In the end they did not find anything. I am back running but still have pain. Mine is in the front, I now believe its the tendone that passes over the tibia about 1/3 the way up your lower leg.

Anyhow, I do remember reading that MRI is done sometimes, but it seems Bone scan is really the best, most conclusive test.

5

OK, time for a brief stress fx diagnostic primer:

#1 If you increased your running, activity and have focal pain, can’t bear weight, etc. and you THINK you may have a stress fx - you do until proven otherwise. No one knows your body better than you (esp the doctor), but you can’t risk an overt cortical fx or the season, so go easy until it can be ruled out.

#2 Most stress fractures won’t show up on plain film X-rays for about 10-14 days for a metatarsal stress fx to possibly never for a tibia or fibular stress fx. Calcaneal stress fractures take about 4 weeks to show (but you have to really know what to look for) and navicular stress fx will never show. You are basically seeing “healing” or a focal periosteal reaction, rather than the fracture itself, which is why the delay.

#3 A CT scan would be the best test to see the bone in great detail to see very fine, hairline fractures. But, it won’t really show marrow edema, or a precursor type stress reaction that an MRI can

#4 An MRI shows everything (fat, soft tissue, bone, muscle, tendon) and the computer can flip flop images, suppress fat, “highlight” bone via a bone window, etc. But, you typically give up some resolution to a CT scan. Some of the newer 1.5 Tesla magnets are giving a pretty damn nice image though, similar to a CT

#5 A bone scan is VERY sensitive and will light up a stress fx every time, but it is not specific. ANY bone injury (bruise, osteoarthitis, etc.) will show the same. There are also a good deal of false positives with these. A positive technetium-99 bone scan needs to be correlated with other studies (X-rays, clinical) to be sure.

Well, that about sums it up - no off into world with knowledge. If only I understood the clincher/tubular tire debate… :0

6

Can an MRI detect a stress fracture sooner than the 2 weeks or that it takes to show on an x-ray?

I’ve developed a pain similar to a shin splint only higher and more towards the back of the calf. After a 12 mile run I can’t put weight on it for 24 hours and walk with a limp for another 48 hours. This has been gradually getting worse for 2 weeks. Doctor requested an MRI after the xray was inconclusive. Should have the results tomorrow.

It started a week or so after a minor bike wreck so I think the MRI may be to verify no blood clots. Just curious if anyone has had experience with an MRI for sfx, usually it’s xray and bone scan.

Supposed to be racing IMFL next month, the timing stinks.

This is why healthcare is so expensive in the US =).

It could be a lot of things, but… Given your circumstances it is very likely an overuse injury. It doesn’t sound like a ‘stress-fracture’ given it’s location. It doesn’t sound like a blood clot as it’s exertional related. It’s likely a soft tissue over-use injury (partial gastroc/soleus tear, hamstrong/itb tendonitis). Regardless, an MRI is a very good test to give a diagnosis.

A MRI is at least as sensitive as a bone scan for ‘stress-fractures’, and much more specific. A ‘stress-reaction’ is just bone edema without an identified cortical defect. A ‘stress-fracture’ is an identified, incomplete cortical defect. They are varrying shades of the same thing. While a MRI can detect blood clots, it is not terribly sensitive, and an order of magnitude more expensive than the best test.

But…

Regardless of what the MRI shows (stress fracture, reaction, muscle tear, tendonitis, even a baker’s cyst or knee arthritis), he will tell you to rest a while, then gradually return to activity. If the pain returns, repeat but rest longer. The sad thing is your doctor knows this, but ordered the test anyway. As a society we’ve become obsessed with diagnosis, above and beyond outcomes.

So, enjoy the rest, watch some football! IMFL is likely a scratch, and I hope you didn’t have a copay for the MRI.

Scott

7

" No one knows your body better than you "

That’s what is bugging me. In 15 years of running I’ve never had anything close to this painful. I can knock a shin-splint out with a block of ice and some rest no problem. This is a thousand times worse than any shin spint I’ve ever had.

The radiologist did confirm “stress activity” which I’m interpreting as the precursor to the full blown sfx.

I’ve been holding out hope for IMFL but I think I’m dreaming. Did anyone else read the letter to the editor in Triathlete a few months back from an athlete thanking the spectators at IMAZ who helped him when his leg snapped? I can’t quit picturing that.

8

I haven’t read all the posts, but here’s my $0.02 - a bone scan is more likely to detect a sfx, as it will show spots on the bone where things are healing. The MRI is for soft tissue things, I think.

Best wishes that it’s NOT a fracture.

9

OK, let’s get this straight(something I actually know about for a change)

Bone scan - a nuclear medicine test, aka “unclear” medicine. Actually a good test for stress fx in the appropriate clinical setting. As has been said, shows activity where there is healing or laying down of new bone.

MRI - more expensive. Exquisitely sensitive to detecting bone marrow edema, such as may be seen in early stress reaction/fx. Excellent visualization of soft tissues. Can show fracture lines, but prob not as good as CT does.

CT - excellent for showing cortical bone. Not great for marrow edema but can show later stress changes such as sclerosis (increased bone density) as well as fracture lines. Becoming much better at evaluation soft tissues due to it’s superior spatial resolution and ability to reconstruct the image data in essentially any plane. Cheaper than MR but more than bone scan.

Radiology lesson over.