How to determine MRI risk without knowing what kind of stent you have.

March 19, 2008 5:08 PM

Should my father be worried about having an MRI because he has a stent that was implanted after a heart attack? (It's supposed to happen in 12 hours!)

My father has been waiting for an MRI (for what is probably a gall bladder problem) while the hospital/doctors sort out what kind of stent he has and whether there is any risk due to ferro-magnetic interaction.

The test has been delayed while this was sorted out. Today he received a phone call from the hospital saying that he was approved and the MRI is on for tomorrow. He asked how the approval was obtained, and the hospital told him that they spoke to his MD to get the details on his stent, and checked with the manufacturer.

However, he tried to call his MD to confirm, and found out that he is on vacation. He also tried to reach his cardiac surgeon, and he is also on vacation.

So that sounds a little worrying. However, the stent was implanted in 2003 at the same hospital where he is having the MRI, so presumably they have the records and could have actually confirmed the safety. Also I see this and this which are comforting without being authoritative.

He doesn't know what kind of stent it is, just that it was implanted in 2003.

He intends to go to the appointment tomorrow and ask for more details before having the procedure, but I think he is inclined to do what they tell him, while still being a little uneasy about the whole thing.

Can anyone point me to resources that would help us understand the risk? The appointment is at 7:30 AM EDT so he won't have time to contact anyone in the morning to get further information. He has to agree to the MRI or not.

posted by lockedroomguy to health & fitness (5 comments total)

It's likely that when they said "we talked to your MD", they mean "we talked to your MD's staff". Medical records stuff like this is not often done by the doctors themselves.
posted by spaceman_spiff at 5:36 PM on March 19, 2008

Having done MRI research for a few years, I can say that no one is going to take concerns about ferromagnetic risks lightly. If they've cleared him for the MRI, they are very damn sure that he's safe to scan.

If he's really concerned, he can ask for an X-ray to clear him before the scan. However, if they've already decided it's not necessary, then I would imagine he'd get charged for the X-ray. Maybe the peace of mind would be worth it to him; only you two can figure that out.
posted by Stacey at 5:50 PM on March 19, 2008

This is in the USA right? The medical malpractice and liability suit capital of the known universe? Which is just to say that if they're saying it's safe I'll be they are 100% sure it's safe. Mind you, if they ask him to sign a stack of papers higher than his medical records when they get there and suddenly need new waivers for some reason, then I'd be worried.

That said I was in an MRI with my metal belt buckle on and the staff said it really didn't matter all that much, and to let them know if it moved. Well, you can bet I was darn well paying attention to any dangerous moverment "down there" and it never moved at all that I could feel.
posted by tiamat at 5:52 PM on March 19, 2008

I should have said--it's in Canada, in Ontario, in a reasonably wealthy and sophisticated community.
posted by lockedroomguy at 5:59 PM on March 19, 2008

I don't know what you want in terms of 'authoritative', but:

Magnetic Resonance Imaging Seems Safe In Patients ...

We elucidated whether exposure to cardiac magnetic resonance imaging (MRI) of patients with implanted intracoronary stents is associated with increased risk of stent-thrombosis, stent-restenosis, or other cardiovascular complications. Forty-seven patients admitted with acute myocardial infarction (AMI) were studied. Twenty-three were included in a serial cardiac MRI study, using 1.5-T scanners with standard gradient systems. The remaining patients were control subjects who were matched for age and gender with the MRI group. All patient had intracoronary stents implanted in connection with primary angioplastic treatment (PTCA) of AMI (n = 21), secondary PTCA procedures due to recurrent angina (n = 22), or both (n = 4). In the MRI group (n = 23, aged 58 +/- 10 yr), MRI was carried out one to five times in each patient a median of 166 days (range, 1-501) after stent implantation. The control group comprised 24 patients, ages 59 +/- 11 yr. The incidences of stent-thrombosis, stent-restenosis, and other cardiovascular complications did not differ statistically significantly between the two groups. In the MRI group, stent-related thrombosis (n = 1) or restenosis (n = 7) was observed in eight cases a median of 102 days (range, 7-547) after MR examination and a median of 318 days (range, 138-713) after stent implantation, compared with nine cases in the control group (thrombosis, n = 1; restenosis, n = 8) observed a median of 147 days (range, 1-267) after stent implantation. No acute thromboembolic or other complication occurred in immediate connection with MRI. The follow-up time was 21.3 +/- 4.5 months. This small study shows no evidence of an MRI-related risk of stent-restenosis or other cardiovascular complications, not even if cardiac MRI is performed early after stent implantation.
posted by Comrade_robot at 6:22 PM on March 19, 2008