# Allergic reaction to an MRI? **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2007, 10:10pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912 "2007-06-21T22:10:33Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [June 21, 2007, 10:10pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/1 "2007-06-21T22:10:33Z")
My friend’s girlfriend just had an MRI and went into anaphylactic shock – which is highly unusual but, apparently, not unheard of. He was wondering: If an MRI technician misses the vein while injecting the patient with gadalinium (for contrast), does that increase the risk of an allergic reaction? ---
**Author:** ![cher3](https://avatars.discourse-cdn.com/v4/letter/c/da6949/32.png) [@cher3](https://boards.straightdope.com/u/cher3)\ **Post date:** [June 21, 2007, 10:24pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/2 "2007-06-21T22:24:56Z")
As I understand it, the risk is there for people with allergies to iodine, so they always ask if you have shellfish or iodine allergies. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [June 21, 2007, 11:07pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/3 "2007-06-21T23:07:07Z")
Sorry, I meant [gadolinium.](http://en.wikipedia.org/wiki/Gadolinium) But the question is, is it possible the gadolinium solution would not cause an allergic reaction when injected into a vein or artery the way it’s supposed to be, but would when injected into the adjacent muscular or fatty tissue? ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [June 22, 2007, 12:11am UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/4 "2007-06-22T00:11:30Z")
[QUOTE=BrainGlutton] Sorry, I meant [gadolinium.](http://en.wikipedia.org/wiki/Gadolinium) But the question is, is it possible the gadolinium solution would not cause an allergic reaction when injected into a vein or artery the way it’s supposed to be, but would when injected into the adjacent muscular or fatty tissue? [/QUOTE] I doubt it. In a sensitized individual, extravasation of gadolinium into soft tissue would typically cause a lesser and delayed response. From [here](http://www.postgradmed.com/issues/2002/05_02/rusznak.htm): “In general, large doses and intravenous administration of an agent are more likely to result in severe reactions than small doses administered by alternative routes.” Gadolinium as a contrast agent, by the way, is known to be considerably safer than iodine-based contrast media. And toxic (as opposed to allergic) reactions due to gadolinium in soft tissue are extremely rare. Still, I guess I shouldn’t have been surprised to find that there’s a cottage industry [in the legal trade](http://www.gadoliniumlawyers.com) capitalizing on patient adverse reactions to gadolinium. Talk about specialization. :rolleyes: ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [June 22, 2007, 1:16pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/5 "2007-06-22T13:16:14Z")
Gadolinium and iodine contrast agents are not useful in the same procedures. Gadolinium has unusual magnetic properties that make it useful in MRIs and other applications. For example, I have a chunk of gadolinium that a magnet will lift if it is cool but not if it is warm. Iodine is useful in XRay procedures. ---
**Author:** ![Neur0mancer\_1](https://avatars.discourse-cdn.com/v4/letter/n/46a35a/32.png) [@Neur0mancer\_1](https://boards.straightdope.com/u/Neur0mancer_1)\ **Post date:** [June 22, 2007, 1:57pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/6 "2007-06-22T13:57:48Z")
[QUOTE=Napier] Gadolinium and iodine contrast agents are not useful in the same procedures. Gadolinium has unusual magnetic properties that make it useful in MRIs and other applications. For example, I have a chunk of gadolinium that a magnet will lift if it is cool but not if it is warm. Iodine is useful in XRay procedures. [/QUOTE] You can also use gadolinium for X-ray based applications, when there is a need for contrast, but the patient has an iodine allergy. There is a new adverse effect of gadolinium that has recently been recognized, rare but serious, happens to people with impaired kidney function. It’s called nephrogenic systemic sclerosis. The OP is not surprising. You can have an anaphylactoid reaction to anything, gado included. GVG (radiologist) ---
**Author:** ![SailBunny](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@SailBunny](https://boards.straightdope.com/u/SailBunny)\ **Post date:** [June 22, 2007, 5:11pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/7 "2007-06-22T17:11:18Z")
Nephrogenic systemic sclerosis is pretty interesting…your skin hardens, its like wood til basically you can’t move. I didn’t get to see the case personally, but it was described to me in detail. Apparently Very Rare, and not much is known about it. Of course I’ve already heard an advertisement on TV by a personal injury lawyer… ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [June 22, 2007, 5:49pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/8 "2007-06-22T17:49:07Z")
[QUOTE=SailBunny] Nephrogenic systemic sclerosis is pretty interesting…your skin hardens, its like wood til basically you can’t move. I didn’t get to see the case personally, but it was described to me in detail. Apparently Very Rare, and not much is known about it. Of course I’ve already heard an advertisement on TV by a personal injury lawyer… [/QUOTE] I had a dialysis patient with it, very interesting. I initially thought he had scleroderma, as I’d never heard of it before. The local university rheumatologist wanted to get a consult from the national guru at Yale, but we weren’t about to send this patient to Yale. He was doing yust fine in prison. 😉 ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [June 23, 2007, 8:04pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/9 "2007-06-23T20:04:37Z")
My friend has another question on his girlfriend’s case: Does pituitary adenoma predispose a patient to anaphylactic shock? ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [June 23, 2007, 8:14pm UTC](https://boards.straightdope.com/t/allergic-reaction-to-an-mri/408912/10 "2007-06-23T20:14:48Z")
[QUOTE=BrainGlutton] My friend has another question on his girlfriend’s case: Does pituitary adenoma predispose a patient to anaphylactic shock? [/QUOTE] Well, pituitary adenomas can suddenly hemorrhage, causing _pituitary apoplexy_, or acute sudden hypopituitarism, and as such are associated with shock, coma, and death. But it’s not an anaphylactic reaction (Anaphylaxis is an acute systemic reaction caused by the release of mediators from mast cells and basophils) but rather due to compression of critical structures in the brain. In general. I would think that someone named **BrainGlutton** ought to know these things. 😉