It is generally safe to undergo magnetic resonance imaging (MRI) scans with stents in place, though a lot of this depends on when the stent was implanted and what, exactly, it is intended to do. Stents are basically small tubes or sometimes springs that help prop arteries open. They’re often used after a heart attack or in patients who are seen as high risks for arterial collapse. One of the biggest concerns people have when undergoing MRIs is that the magnetic force of the scans will somehow knock the stents out of place. In most cases this fear is unfounded, though it’s still really important for people who have these devices to inform their care providers before undergoing this or any related procedure. It’s often the case that the care team providing the MRI isn’t the same as the one that installed the stent, so they might not be aware that it is present. When everyone is on the same page when it comes to medical history, precautions can be taken to ensure that everything goes smoothly.
Understanding Stents Generally
Medical professionals have been using stents for heart patients for decades. A stent’s main goal is to help keep the major arteries open so that blood can quickly and easily flow through them. There are a couple of reasons why arteries collapse or shrink, usually with age and often as a consequence of some sort of heart defect or problem; stents are an easy and usually effective treatment option. Most aren’t permanent, though, and people who have them do typically need to exercise certain precautions when it comes to keeping them in place and protecting their heart health generally. In nearly all cases medical scans aren’t on the danger list, and as such is it generally safe to have an MRI with a stent.
MRI Basics
MRIs are essentially scans of the body that can give diagnosticians a very clear view of certain organs or internal processes without actually having to surgically open a patient. They use magnetic energy to specifically identify the location of internal organs, glands, and passageways, and in most cases the results are remarkably clear and accurate.
The procedure is considered “noninvasive” because it doesn’t involve incisions or internal disruption, but it isn’t without its risks. Patients usually have to spend time lying very still in an MRI machine, which is a contained space where controlled magnetic waves penetrate and bounce. Certain implants and internal medical devices can cause problems during an MRI, particularly those that are made of metal; metal can cause the magnetic and radio waves to change frequency, and these sorts of devices can also be themselves impacted and might become less effective. Stents are typically considered “MRI-safe,” but anyone with a stent in place would be wise to get a professional opinion on their specific situation before proceeding.
Concerns Over Magnetic Field
The question of whether having an MRI with a stent is safe usually stems from a fear that the magnetic field generated by the MRI will displace the stent. The majority of modern coronary artery stents are made from materials that do not displace as a result of an MRI, and as such, even the strongest magnetic waves won’t impact them. A group of researchers in Texas in 1998 reviewed all major coronary stents then available on the world market and found all of them safe in regard to an MRI.
Several studies have shown that an MRI can be performed safely within a day of stent implantation, though many radiologists advise waiting several weeks before undergoing this or any related procedure. Most of this owes to healing time more than inherent dangers, though. There is not usually any danger to stents from metal detectors.
Older Stents
People who had a coronary stent placed after 1998 may have a drug-eluting device. These stents are similar to older bare metal stents but are coated with drugs that are released over time. This helps prevent the blood vessel from re-closing. These stents also are generally safe during an MRI, but more caution may be needed to ensure that the magnetic activity doesn’t change the drug distribution schedule.
Importance of Consultation
Many people with coronary artery stents also have other implanted devices that include coils, filters and wires. While having an MRI with a stent is safe, it may not be safe to have a MRI with those devices. The surgeon who performed the surgery should have more information about what devices were implanted and whether an MRI is safe, and MRI technicians who have a patient’s complete medical file can usually make better judgments, too.
Non-emergency MRIs for patients with stents may delayed while the MRI facility consults with the patient's physicians to confirm the safety of the procedure. To avoid such a delay in emergency situations, a patient is advised to keep a card with him explaining what devices he has implanted. The card should include the phone number of both the surgeon who performed the implant and the patient's regular physician.