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.