CT scan - using Gastrografin - any view please?

Hi all - just wondered if anyone had experience of using Gastrografin prior to ct scan? I believe it would not be advisable for people with hyper-thyroidism - but I'm just a bit concerned re the accuracy of TFT in the coming months when the lab will always refuse to test T3.

I'm Hypo for few years on 150mcg Levothyroxine.

'Gastrografin is an X-ray contrast medium or X-ray dye that is taken orally or rectally when X-rays of the gastrointestinal tract are being taken. All X-ray dyes, including Gastrografin, contain iodine.'

The results of protein bound iodine (PBI) and radioactive iodine uptake studies, which depend on iodine estimations, will not accurately reflect thyroid function for six months, and possibly as long as one year, following the administration of diagnostic enteral radiopaque media.

Thyroid function tests, if indicated, generally should be performed prior to the administration of any iodinated agent. However, thyroid function can be evaluated after use of these agents by using T3 resin uptake and total or free thyroxine (T4) assays which are not dependent on iodine estimations.

Thanks

Terri

7 Replies

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  • I'm afraid I am probably not going to be much help. All I have found out is that you must tell the radiographer if you have any type of thyroid disease. It can affect thyroid function for several weeks afterwards. If you are due to have iodine test for your thyroid soon afterwards you must let them know that you have had Gastrografin. I think normal thyroid function tests (blood tests) should be ok though after the initial few weeks.

    Here is a copy of a patient information leaflet

    xpil.medicines.org.uk/ViewP...

    Sorry I couldn't be more helpful or specific.

  • Thanks Carolyn x

  • >The results of protein bound iodine (PBI) and radioactive iodine uptake studies, which depend on iodine estimations, will not accurately reflect thyroid function for six months, and possibly as long as one year, following the administration of diagnostic enteral radiopaque media.

    I doubt that you'll be having either of these tests. The protein-bound iodine test is a old-fashioned test which is no longer used (AFAIK). Radioactive iodine uptake studies are used to assess hyperthyrodism, but you said you're hypo.

  • Thank you for taking the time Bobbin2 x

  • Hi, I suffer from thyroid problems , sometimes too low and then too high. Regular blood tests are being done. Next week I have to go for CT scan on my bowel and will have to drink gastrografin. I'm really scared in case it affects my thyroid. I think I may cancel the scan.

  • Hi Teddybear123 - Please see my similar question and very helpful replies regarding Gastrografin. I didn't have any adverse effects after having the treatment but if you are concerned then please talk to the people treating you to set your mind at rest. Good luck

    Terri

  • Thank you Terri66. Had another chat with the consultant and he assures me there will be no problem !! Here goes.............

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