Use of iodine in CT and PET scans

[FleetRose]

I am aware of the danger of taking iodine supplements and their possible effect on the thyroid. Does it follow that investigations requiring intravenous iodine as in some CT and PET scans pose a risk to people with Hashimotos? My rheumatologist is suggesting I have some such investigations and it is worrying me. When I've phoned the Xray department, not surprisingly, they say there is no risk but I'm not confident they would know about thyroid conditions.

I would welcome any thoughts or knowledge on the subject. Thank you.

[helvella Administrator Thyroid UK]

There is a lot of information and some of it is very confusing.

Some iodine contrast agents do not leave much free iodine. So they are not necessarily as bad as they appear at first look.

I usually suggest reading a bit on this site - but there is an awful lot there!

radiopaedia.org/search?scop...

[FleetRose in reply to helvella]

Thank you for the link helvella. I've started reading but there's lots to explore here!

[helvella Administrator Thyroid UK in reply to FleetRose]

There is!

Sorry it is too much but maybe adjusting the search would cut down the number of documents it finds?

[Lottyplum in reply to FleetRose]

Just to say, I have Hashi, had a CT scan last year, was concerned, talked with lovely staff nurse involved, went ahead+had no side effects or issues after.

[greygoose]

I have Hashi's - well, Ord's, actually, but same difference - and I've had lots of scans using iodine contrast. And it's never had any effect on me - as far as I know! I've never felt anything, anyway.

[FleetRose in reply to greygoose]

Thanks greygoose. That's reassuring to know.

[greygoose in reply to FleetRose]

You're welcome.

[bantam12]

I have a lot of scans, 5 CTs + 1 MRI last year, 3 CTs so far this year and all with contrast, never had any issues during or after.

[arTistapple]

I was certainly worried recently when having a CT Scan of my heart. Same experience as you phoning the department AND immediately prior to getting the dye, told no problem and it was left to me to decide. It almost seems like a form of gaslighting. No info about process but told it’s your decision - your life might depend on it though!

Anyway as far as I am aware no symptoms arose from the dye/process. I have had a reaction after a previous angiogram - desperate to pee. Turns out that’s a ‘known’ issue. At that time I had no idea about issues with iodine (did not know I was hypo either) though.

This time no recent CKD testing since so don’t know if the dye has affected kidneys BUT no problems experienced.

Obviously not something we want to do often!

[humanbean]

I've never had problems with contrast. I've been given two different kinds - iodine and gadolinium.

The only thing I remember being mentioned in the lead up to getting the contrast was that I should drink plenty of water in the 24 hours before getting injected with contrast . The idea is to make certain that the patient is well hydrated.

In the day or two after getting scanned with contrast I have been instructed to drink plenty of water. This is because contrast can be hard on the kidneys and being well hydrated before and after helps the body to flush the contrast out.

[FleetRose]

Thank you to all those who responded to my post about use of iodine in PET/CT scans. I will certainly ask questions and check if it is absolutely necessary for my particular investigation. I see a lot of people have had no problems at all but I will still proceed with caution!

Thank you again.

[nightingale-56]

I had violent, projectile vomiting 5 times after having a contrast MRI in 2015. I am hypothyroidism after having sub-total thyroidectomy for Graves.