Medical professionals use inferior vena cava (IVC) filters to prevent blood clots and other material from interfering with the operation of your heart’s inferior vena cava. They generally insert these filters through a vein and use imaging technology to place them near your heart. These filters are not always compatible with MRI machines. IVC filter and MRI compatibility depends on both the filter type and the amount of magnetism the MRI is using.
When manufacturers construct IVC filters, they test the filters and designate them as either “MR safe” or “MR conditional.” Patients whose IVC filters are not susceptible to becoming magnetized can undergo MRI scanning at any time after surgery. Patients whose IVC filters are potentially at risk for becoming magnetized should wait at least six weeks before undergoing an MRI scan.1
Two types of filters that may become magnetized are:
- The Gianturco-Roehm Bird's Nest® Vena Cava Filter (manufactured by Cook Medical)
- The stainless steel Greenfield® Vena Cava Filter (manufactured by Boston Scientific)
There are exceptions to the six-week rule. If there is no reason to suspect the device is out of place and the physician considers a scan necessary, then medical staff may decide to go ahead with the MRI.1
IVC filter manufacturers usually test filters at fields of up to 1.5 T. However, some filters have also been tested at higher field levels — up to 3 T. If you anticipate MRI scanning is likely for you in the future, you may want to select a modern IVC filter that has been tested at the higher field level.
Although IVC filters and MRIs are generally compatible, you should try to select an "MR safe" filter if you anticipate a scan in the future. If you are considering pregnancy, you should ask your doctor about the safety of MRI scans for pregnant women.
In 2010 the U.S. Food and Drug Administration issued a general safety alert2 about IVC filters, which outlined potential medical risks associated with their long-term use, such as deep vein thrombosis and filter migration. If you or a loved one has been injured as a result of IVC filter usage, a medical device attorney may be able to help you file a claim.