IVC Filter Composition, MRI Dangers and Effects
Most IVC filters are made of non-ferromagnetic materials; however, there are a few that are weakly ferromagnetic.3 Due to this, IVC filters can fall under the MRI Safe and MRI Conditional categories. Rarely will one find an MRI Not Safe IVC filter, as most of the steel, and other ferromagnetic material devices have been discontinued via the FDA.
IVC filters are attached to the vena cava via hooks on their ends. Some are compression springs, which compress outward onto the side wall of the vena cava; however, they still have small hooks that retain their location. These hooks aid in the anchoring and healing process, as they allow the tissues to ingrow around them, securing the IVC in place. It is unlikely, then, after 4 to 6 weeks of healing, that an MRI of 1.5 tesla, up to 3 tesla, will cause any level of dislodging to occur for the IVC filter.
Studies of MR examination of both animals and humans with implanted IVC filters have thus far not reported complications or symptomatic filter displacement.
Several animal studies have even used “real-time” MR for the placement of IVC filters to check for rotation, sheering, and other artifacts, and have thus far turned up no results.
As part of the routing survey for MRI studies, patients who have IVC filters will often need verification from the doctor, or medical records, to state that the IVC is safe for the MRI. Most patients with weakly or non-safe ferromagnetic implants will be given a card, which they keep on their person at all time, which can help isolate if it is safe to do an MRI.
For patients who have been denied MRI scans for safety reasons, doctors usually recommend the CT scan with contrast as an alternative.
Read more about this topic: Inferior Vena Cava Filter
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