PMRGCAuk
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PET and Cortecosteroids

I have received my appiontment for a PET-CAT for the 12 of Feb which I had planned on cancelling after learning on here that PET scans dont work on patients that are taking prednisone. Since I am feeling increasingly unwell and bed/sofa bound, I re visited this article about the PMR/GCA spectrum.

academic.oup.com/rheumatolo...

In it, I think it says that F-FDG PET "demonstrates tracer - uptake in large vessels" promoting the revision of PMR DX toward GCA.

So now I'm thinking that when revising a patient with a PMR diagnosis, wouldn't that patient no longer be steroid- naive?

Im not sure if the PET they are doing on me is the same as the F-FDG PET. I was told that the test would require a contrast dye which maybe" F-FDG" refers to?

Meanwhile, I remembered that a friend of my husband is a cardio vascular surgeon that for some reason never operated and only does Doppler. He would gladly do one on me as soon as I ask him to, to rule out GCA, but I'm not sure if he would be capable of doing it for GCA, as in all the literature I've read, it says the doctor/technician performing the dopplar have to be specifically trained.

Good thing PMR. /GCA is rare here in Spain.. No one takes me seriously while I keep reading posts on the forums that my current symptoms constitute a medical emergency.

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I may be the exception, but I got a definitive diagnosis of PMR by PET scan after over a year on Pred. I was on over 10mgs at the time. Prof. Dasgupta ordered the scan because I had some atypical symptoms and whilst he didn't think I had PMR he was concerned I may have GCA or some other large vessel issues.He had to eat his words because the inflammation was present in both my shoulder and pelvic girdles- definitely PMR. It has been invaluable to have an irrefutable diagnosis in the 5 years since then.

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Oooh - that's interesting. We decided the other week there isn't likely to be much to see after the time I have been on pred. But presumably you need to have some symptoms? One has to assume surely that if you have symptoms - you may get a result on imaging?

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I'm confused because Prof. Dagupta con authors both papers, the one with the drawingsvand one that spec8ficallt addresses the effectivity of PET in patients on Cortecosteroids.

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Do you mean this one:

academic.oup.com/rheumatolo...

I get so used to always mentioning the first author - which is the one that matters when looking for it!

There is this one - with a figure of the image from a resistant PMR patient who then developed GCA. It does mention a decrease in uptake after 3 months of pred treament.

medscape.com/viewarticle/73...

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I would contact the department and discuss it with the radiographer. If they don't know - no-one does.

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Yes, I presume it was because there was still inflammation there despite the Pred. In fact, my CRP and ESR have very rarely been normal all the way through and I have never been able to get below 9mgs without a flare, so maybe the Pred. is not so effective in my case? I have not had one day without pain that I can remember, although that could also be the OA- who knows???

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OTOH - my CRP has never been raised (bar once and that was a one-off, and taken during an atrial fibrillation episode I realised later). I discovered a few weeks ago that my ESR did get to the really dizzy heights of mid-teens at about the same time when I was on Medrol which did nothing for me at all - but never to a level any doctor would turn a hair about.

The other thing I'd like to see is a check of how much pred we actually absorb - bet you and I are nearer the 50% bioavailability than the 90% end.

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I really feel like I need a lot more Pred, I was fine at 7.5 for over a month and then I got all the symptoms so I went all the wzy up to 15 to try, but saw no difference.

Your story Suzy, is very similar to mine, except I haven't been definitively diagnosed yet - I had to change rheumies and the second one believed that my symptoms were more in line with GCA than PMR. So maybe something about PET scans has improved since Prof Dagupta wrote that paper about the use of PET. Or maybe in the paper about the spectrum, the reference to PET is only for Temporal artheritis, while the other paper that talks specifically about the effectiveness of PET only in steroid naive patients is reffering to imaging of only the aorta??

I aplogize for my increasingly difficult- to- read writing. My New Years resolution is to take a Writing 101 course.

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My brain is hurting! I can only go on my own experience and it is too late this evening for me to understand what we are talking about!

Your writing is fine,Gaijin- it is my lack of brain power that is the problem!

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Think it is the weather - Storm Eleanor/Burglind has been raging for too long!!!!!

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No, its my writing...bu thank you for saying that...

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Forgot to say that having learned from you, Suzy, that you were diagnosed through PET after you were already on prednisone, and by Prof. Dagupta, no less, makes me think I should go through with the PET. Thank you for sharing.

The only doubt I have is that the locum rheumi that ordered the PET scan called the radiology department in my presence and asked them which imaging test would be best to "rule out aortitis". I'm wondering if diagosing PMR with PET is different from diagnosing large vessle involvement... in terms of where on the body the imaging is done on and what the signals are supp8sed to puck up...

Sorry PMRpro.. Hope you can understand this

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If there is inflammation the PET scan should pick it up anywhere - that is what happened to Suzy I think. Dasgupta thought it might be arteritis rather than PMR which typically shows up in shoulder and hip joints. But it turned out there was fluorescence from joints too - they were inflamed.

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I think it's fair to say that they only thing they know for definite is that Prednisolone interferes with the PET signal which can lead to false negative scan results. That isn't the same as saying that it's impossible to get a positive result whilst on pred.

I don't know what the situation is like in Spain but PET scanners are a scarce, expensive resource in the U.K. ( there are only 3 for the whole of Scotland ), why would you spend over £1500 and give the patients a big whack of radiation if there is a strong chance that the scan won't show what you want?

PET scanning in Vasculitis is still in its infancy, as far as I am aware it's not yet been properly validated, MRA is an alternative and they have more data to support its use. If the PET is negative it doesn't mean you don't have large vessel involvement or PMR.

PMRpro is right to mention the radiologist, I wonder if they know the length of time you have been taking pred?

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Found this, technical but a very good discussion on CT/PET and PMR, GCA and large vessel Vasculitis.

hindawi.com/journals/bmri/2...

I had a CT/PET around a month after tapering prednisolone to zero after 2 years.

It showed inflamation in all the areas I had pain, hips, shoulders and ribs. It also hinted at some inflamation in my thoracic ascending aorta which is dilated ( aneurysm ).

The maddening thing was that the Radiologist and various Rheumatologists couldn't agree on the interpretation of the inflamation, the opinions ranged from " biomechanical stress " to evidence of enthesitis to nothing! A scan is only as good as the experience of the person who interprets it as well unfortunately.

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Thank you Keyes, for that article. It is very technical but I did understand the gist of it.

Now I know why every rheumi I've seen asks me why I have a Japanese name and surname (I don't look Asian but I am 25% Japanese) .. they are probably trying to rule out Takayasu's arteritis..

Anyway, this paper has convinced me to go along with my rheumi's plan and ditch the idea of calling our friend for a dopplar. Hopefully nothing major happens before my next appointment.

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Well, that was what my concern was. According to my husband, they want to do the PET scan for thier own " research" data. There must not be very many PET scanners here either.. Mine is to be done in a hospital way across town, which incidentally is the same hospital that is doing an international study in PMR GCA( I was told this by someone on this forum.)

Spain's public health system has no such thing as NICE, consultants prescribe whatever they want.. This PET scan had to be approved by the head of the department.. I was surprised that it was approved as they have access to my medical history and how long I've been on Pred.

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