Hmmm....I'm looking at my card right now and it simply says "Studies have indicated that all CarboMedics Inc....heart valve replacement and repair implants are MRI Compatible." Does Justin's valve require special settings to avoid problems in an MRI? Pyrolitic carbon responds to a strong magnetic field, (it's either diamagnetic, retromagnetic or both, I can't rembember, but a sheet of it can actually be levitated over a rare earth magnet.) but I was told by the docs that an MRI doesn't exert enough force to overcome blood flow or pressure, which dictate the position of the valves moment by moment.
I'd be curious to know if this is not true for all pyrolytic carbon valves.
Justin has a tissue valve which the frame isnt magnetic, but to be honest we spend more time before MRIs and when schedualling them, talking about his pacer wires, so i dont remember if there are any setting for MRI they need to use because of his valve or other parts he's had replaced, i dont think so tho.
I know from those talks, beside the magnetic issues one of the main concerns with metal and MRIs is if they can get too hot, so beside settings they discussed time frames.
Anyway back to St jude and the patient card, from their site under patient concerns. (BTW they said you should have the card within 90 days) it says
"MRI Testing
If you are told you need to have an MRI (magnetic resonance imaging), tell the doctor that you have an artificial heart valve
and show your ID card, which contains important information about how to perform an MRI safely with your valve. Your doctor or MRI technician may request the following information:
Non-clinical testing has demonstrated that St. Jude Medical heart valves and repair devices are MR conditional. They can be scanned safely under the following conditions:
Static magnetic field of 3 Tesla or less
Spatial gradient of 525 Gauss/cm or less
Maximum whole-body-averaged specific absorption rate (SAR) of 2.0-W/kg for 15 minutes of scanning
If you have questions or concerns about this and other diagnostic tests and your heart valve, please talk to your doctor.
http://health.sjm.com/heart-valve-answers/daily-life/everyday-concerns.aspx
I noticed that mentioned a time frame too, so my guess that would be because of heating since I dont think wether it is magnetic or not would cause problems after a certain time. altho i could be completely wrong of course.
ps
ok I found info on Justin's tissue (edwards perimount) valve and MRI safety/settings and it says "Testing of these devices in a magnetic field of 1.5, 3.0, and 8.0 tesla has shown that these devices are safe and compatible during MRI (magnetic resonance imaging) procedures" and doesnt have any settings or times