Usefulness of Bone Scan

[EsqEquestrian]

Hi all,

Hope everyone is staying safe and healthy during this time!

I’ve read just about all of the threads regarding bone scans (nuclear scintigraphy), but there aren’t any recent ones so I thought I’d start one to share my journey. My horse is going to our local equine hospital for a scan this Thursday, and I just wanted to inquire as to whether anyone has found it useful at pinpointing lameness issues. I know it can’t necessarily diagnose the issue on its own, but can narrow down “hot spots” in order to further image and explore those areas.

Just as a little bit of background, my 9 y/o horse has been not fully stepping under himself with his right hind for awhile. About 5 months ago we injected his hocks (after x-rays showed some arthritic changes), and that seemed to help for a few months. However, I have a feeling that perhaps we were treating a symptom and not the main cause. Vet recommended the bone scan after our most recent lameness exam. She blocked up to his hock, but he was still lame behind.

Any information and anecdotes would be much appreciated. I will share updates after the appointment on Thursday. Thank you!

[joiedevie99]

Have you ultrasounded the hind proximal suspensories? IMHO, hock injections “work” for some period of time because the steroids disperse into the top of the suspensory ligament. After 6-12 weeks, things start looking worse again because hocks weren’t the problem.

To your question, yes - I know several people who have gotten answers after a bone scan. One friend was especially lucky, horse lit up in only one area on the bone scan - and the follow up diagnostics the next day found the issue. I think it’s much more common for a few things to light up, and you have to figure out which one or two or three are real problems.

[leheath]

I had my 10yo horse bone scanned last week. There were some performance issues that had been escalating for some time - took a very long time to warm up even in hot weather, started stopping at jumps, couldn’t hold the lead behind when turning to the right. Chiropractor found her reactive in the SI, right hock (she toes out significantly on this leg), and left front (typically compensatory for right hind issues). She flexed completely clean, both hocks x-rayed clean, and left front also clean on x-ray. Back and neck x-rays also clean. Only sign of issues during the lameness exam was reduced flexibility in the pelvis (imaging the SI is very challenging so a bone scan was recommended). So we did a bone scan. Before doing so, I discussed with the vet what might be found and what it might tell us. He showed me some examples - foot issues, suspensory issues, and inflammation or arthritis in areas that were not “obvious.”

My experience was as @joiedevie99 describes (and vet indicated was most common) - there were a few things that lit up and we focused on the 2-3 areas that made sense based on the history of the horse, clinical exam results, and the performance issues. I had both hocks and the SI injected. It is too soon to tell if that has worked (odds are the hocks are compensatory due to the SI issues and the SI issues are very likely to be long standing and not permanently fixable) but I thought I’d at least share my experience.

[ndirish07]

Full disclosure: I have not had a bone scan done on my horses. However, my vet has recommended it. I decided against it. I had friends who have had bone scans done on their horses and it showed multiple areas of inflammation that needed additional diagnostics. They did not get an “answer” from the test. As others have suggested a bone scan is not going to diagnose the issue, but rather point you, hopefully, in the right direction for additional tests. For my horse, given his presentation, I preferred to just start blocking rather than a bone scan. Had he a more chronic presentation, subtle, or just all over issues, I might consider it.

Given what you’ve said about your horse, I too would be looking at the hind suspensory. Did your vet specifically block the suspensory? Hock injections can make that feel better for awhile, and horses with more chronic suspensory strains will feel good one day and not so good the next over a long time before it’s noticed.

[ToN_Farm]

I would look at the stifle both with x-ray and ultrasound. Yes, I have had the bone scans on a couple of horses. One full body scan and others parts of the body. It was not helpful in my cases. Perhaps they have improved over the years and also vets may be more skilled at interpreting them. At one time, there was evidence of things lighting up that weren’t a problem and things not lighting up that were.

[EsqEquestrian]

@joiedevie99

Have you ultrasounded the hind proximal suspensories? IMHO, hock injections “work” for some period of time because the steroids disperse into the top of the suspensory ligament. After 6-12 weeks, things start looking worse again because hocks weren’t the problem.

To your question, yes - I know several people who have gotten answers after a bone scan. One friend was especially lucky, horse lit up in only one area on the bone scan - and the follow up diagnostics the next day found the issue. I think it’s much more common for a few things to light up, and you have to figure out which one or two or three are real problems.

Thank you! Vet did not mention looking into hind proximal suspensories, so I will see if the hospital can ultrasound them while he is there.

[IPEsq]

It was not helpful in my experience. We debated between injecting the SI and doing the bone scan first. Opted for bone scan. It showed some inflammation in the back as the most significant but everything was pretty mild, including any uptake in the SI. Subsequent images showed no changes from images done 2 years prior. We injected the back and had some good results for a couple of weeks. But we learned that if we put steroid pretty much anywhere, he felt better for a couple of weeks. So, we concluded it was the systemic effect of the steroid that was the significant response. Turns out the primary issue at that time was in fact the SI and we wasted many more months before we treated that.

But on the other hand, I have known other horses in similar situations that did get pointed in the right direction as far as treatment from the bone scan results. Especially considering that the expense of the bone scan was the last straw for my insurance company with that horse, I would hesitate to do it again if it seemed like I could spend the same amount of money or less on different diagnostics to find the issue.

[Tee]

I have a (then) 9-year-old Morgan gelding we’d been trying to diagnose for close to five years. Four different vets, most of them ending with a ‘huh, weird’. He wasn’t LAME, but he was off, with some other weird stuff (couldn’t bend right, having issues stepping down off of a tiny bridge, things like that). I kept saying it was in his back, but his back palpated fine and no one would go any further with it.

The bone scan showed a tiny, tiny hot spot in his back, and his hocks and splints lit up. The vet consulted with my regular vet and while he didn’t think the back was anything to look at, he did x-rays. Turns out he had kissing spine, and w/o the bone scan, we’d never have found it.

[Peggy]

I’ve generally had “good” results with them, with good in quotes bc sometimes you find out what you may not have wanted to. Two different horses - found neck issues that were not at all apparent otherwise bc horse was off in front (one horse) or behind (other horse). Second horse turned out to be a medley of issues (including and likely driven by the neck) that were, in the end after three years of treatment and rehab with a period of eight good months in there, unfixable. Most recent horse (yes - three horses, five bone scans, twelve years) we knew it was in the foot but did the bone scan so as to get a better diagnosis via MRI. It was useful for that and gave us a bit of additional information, which may or may not have changed the course of treatment or outcome.

[SolarFlare]

It was useful for my horse (similar presentation - not tracking up properly LH). We actually did quite a bit of diagnostics before sending to the bone scan, so yes it gave a pretty clear answer, since the hospital also had very detailed records of everything else we’d already done

I actually went the opposite route of IPEsq - I decided to inject the SI before a bone scan, as I was pretty sure that’s where the problem was (note: we’d already eliminated the entire limb up to the stifle, including hind suspensory). It helped for about 3 months, then back to square one. The bone scan actually identified that the issue WAS the SI, but it was soft tissue damage so required stall rest and then rehab.

[endlessclimb]

Two horses, two bone scans.

Not terrible helpful either time, though one did lead to a biopsy (why the soft tissue took up the radioactive material, no one could explain) which was diagnosed as lymphoma.

The first the points of both hock lit up. What? They took about a million xrays trying to find a fracture, scrubbed them silly thinking he had peed the radioactive material on them, the works. Could never find out why they both lit up.

I’m not sure it’s a route I would take again, personally.

[blueribbonpaint]

I found it useful for my horse earlier this year. He had a soft tissue injury that we had been rehabbing but he just wasn’t coming back from. I spent a lot of time and money continuing to treat this issue but my vet wasn’t certain his issues were caused by it. He was like many of the other horses on this thread, sound but NQR. We took him for a bone scan and found other spots in addition to the known issue to address.

I have insurance so the scan was covered. I liked that it was done standing so there was little risk and more affordable than an MRI. Good luck with your horse, I hope you get some answers.

[EsqEquestrian]

Thank you all so much for your input and experiences. The bone scan is today, so I will update when I have some more information. I’m just hoping that my insurance will cover the procedure at this point, since my policy excludes “degenerative disease/arthritis.” If not, hopefully it will still be money well spent! Thanks again.

[mollymoon]

It was useful for me. We had an issue with mild, intermittent lameness that appeared to move around between 3 limbs. At first visit, we thought it was left front based on a quick eval while the vet was out there for another horse. At the second visit later that week, we started with a lameness workup using flexions, lunging, and under saddle. Lameness appeared to have moved to the left hind, so we blocked up to the upper suspensory and got a sound horse on the left hind, but slightly off on the right hind. We suspected left hind PSD, but vet wanted to come back another day and do some more definitive diagnostics. At the third visit a week later, we planned to ultrasound the left hind suspensory and block the left hock in order to make sure it was the PSD, but horse was completely sound. We put the horse back into light work for 2 weeks, and then the vet came back for a re-check. At this 4th visit, horse was more off on the right hind than the left hind, with reactivity to SI palpation. We x-rayed both hocks, and found arthritic changes in the right hock only. At this point, vet recommended a bone scan in order to evaluate SI, soft-tissue in left hind, bone remodeling in right hock, and check for any other possible sources of pain. The bone scan indicated mild bone uptake in the left hind fetlock, left hind hock, and a few areas of the thoracic spine. The “hottest” spot was the right hock, which we already knew from X-rays was arthritic, but there was no SI or soft tissue activity anywhere. Based on the bone scan, we x-rayed the back and left hind fetlock. The fetlock was clean, so no treatment recommended there. Back X-rays showed very early, very mild spinal impingement (KS). We decided to inject both hocks and a few vertebrae. After the injections, we did 3 weeks of hand walking/lunging, and are 2 weeks into 3 weeks under saddle with no jumping. So far, horse is sound, his back musculature is improving, and he seems more comfortable in work. We have a re-check with the vet next week, and will consider adding acupuncture based on the results of that exam. Without the bone scan, we wouldn’t have known about the newly-developing KS, and we wouldn’t have been able to rule out a mild left hind suspensory injury, which by that point would have been 4-6 weeks old.

[EsqEquestrian]

Hi all,

Just thought I’d provide an update on this in case it helps anyone else. I received the results of the bone scan, and several areas “lit up.” Most notably, my horse’s navicular area on his front left, his bilateral hocks, and also in the lumbar/sacral area (I believe the vet said L6-L7, end of lumbar and beginning of sacral area). She did further diagnostics on the back including x-rays and a rectal ultrasound, and found what she described as degeneration and possible herniation of that disc. I meant to ask if this is the same as kissing spine, since I am rather uneducated in this area. The back is her main concern, and the prognosis is unfortunately guarded. She did recommend proceeding with injections to see if it helps, but ultimately said that it can be a reason for early retirement.

He’s going to have x-rays of his feet done tomorrow to see what’s going on with the navicular area. She said he blocked sound to the hoof on the left.

Thank you all for your input and assistance. I will update with any additional information I receive in the next few days.

[IPEsq]

Lumbar or LS disc problems are not the same as kissing spine. KS more often occurs with the vertebrae that aren’t fused—it is the overriding of the dorsal spinous processes. The disc is of course between the vertebral bodies. It is not a good diagnosis if that is the issue. There is a lot we don’t know about horses and spinal discs (such as in the neck) but that is one where degeneration is known to be limiting. If the disc isn’t herniated then you might be able to manage the rest of the issues in that area with injections.

Ugh I’m sorry, all of that sounds like not the best news.