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MRI Safety & Your Pets

Fri, Nov 15, 2013

MRI Safety & Your Pets

Amazing technological breakthroughs have brought about advances in veterinary care that even a few years ago would never be considered viable. One of the most important diagnostic tools that veterinarians have in their arsenals is Magnetic Resonance Imaging (MRI).  MRI is an advanced, noninvasive procedure that uses powerful magnets and radio waves to create pictures of the targeted area including bones, soft tissue, and organs. MRI-assisted surgeries have been shown to reduce complication rates for invasive procedures. Images captured as a result of your pet’s MRI provide your veterinarian and veterinary radiologist detailed information about any functional or structural abnormalities your pet may have.  In addition to diagnostic applications for pets, farm animals, even more exotic creature (think lizards, snakes, even sea lions), MRI is invaluable in research for a wide array of veterinary practice areas ranging from ophthalmology (diseases of the eye) to infectious diseases to orthopedics, and many other conditions in between.
Is an MRI Safe for Your Animal?
MRI has been used in human medicine for more than 20 years and in veterinary medicine for more than 10 years. During this period, complication rates for nearly 8 million people who have had an MRI have been very low. Data collected for animals shows similar results.

Potential Risks/Issues
So what are potential risks for your pet when undergoing an MRI?

Anesthesia.

Just as in surgical procedures for humans, anesthetizing your pet carries the greatest, yet still quite minimal risk of the elements associated with the MRI process. A veterinary anesthesiologist gives your pet many of the same medications that humans receive during the same “people” version of the MRI procedure. To reduce the risk of complications that could be caused by anesthesia, your veterinarian will complete comprehensive blood work and any other testing needed. Results are reviewed prior to the MRI appointment so that your pet’s anesthetic plan can be tailored specifically to the animal.

During the brief MRI procedure, your pet’s heart rate, respiratory rate, blood pressure, blood oxygen concentration, and other parameters are closely watched.
It’s important to note that in many instances, an MRI now takes the place of what would have required invasive “exploratory surgery” that post-operative recuperation, healing of the incision, and an increased risk for infection. By minimizing anesthesia time and dramatically reducing post-operative complications, the end result is a better outcome for your pet.
Trained Technicians

Reputable veterinary practices will allow only trained technicians to operate MRI equipment. Individuals with no training have no business operating this equipment. Don’t hesitate to ask your veterinarian if his/her staff is trained to handle and operate MRI machines.

Limited Knowledge by Owners of Animal’s Medical History

Not everyone who has a pet scheduled for an MRI has a full and accurate history of the pet. The pet could have been rescued or adopted from a shelter. Conversely, the pet could have ingested a foreign object made from unknown material. Whatever the situation, not knowing whether a pet has ingested metal can be potentially hazardous for the pet and the technician involved in administering the MRI.
It is important to note that there is non-magnetic (non-ferromagnetic) and magnetic (ferromagnetic) that could be located in the body.
Non-magnetic metals are generally surgically-implanted in the body. When an MRI is performed, this metal appears as a black hole on the image. It is not harmful to your pet or to the technician.

Magnetic metals can be a problem and must be investigated by the technician. Examples of this type of metal includes shrapnel, welding shavings, metal shavings, bbs, bullets. Because of the power of the magnet, materials containing this metal will be drawn to the magnet, causing potentially very serious injury. Metal shavings in the eye, in particular, can be very dangerous. If you know or if you even suspect your pet has some type of metal material in its body, be sure to tell the veterinarian and technician.

MRI & Microchip Incompatibility

It is important to note the issue of microchip compatibility and the use of MRI. Microchips have become a popular way to register information about pets so that if the pet becomes lost, the chip can be an important part of the identification and location process.

However, according to “Guidance for Industry and FDA Staff – Class II Special Controls Guidance Document: Implantable Radiofrequency Transponder System for Patient Identification and Health Information,” “MRI incompatibility” is another potential health risk associated with microchip implants. The publication states that certain tests should be performed in order to demonstrate MRI compatibility. The FDA also says it is important to “address the EMC [Electromagnetic Compatibility] concerns for implant exposure to the significant magnetic and radiofrequency emissions from MRI, including concerns for implant malfunction or damage from MRI exposure and the use of the scanner during MRI procedures.”

Unfortunately, standards for medical implant devices designed for animals are not held to the rigor of FDA requirements as are their counterparts for human patients. As a result, devices are made as inexpensively as possible with no concern for the types of materials used to make the implant. The result can be implants containing ferromagnetic metals that will react negatively to the MRI equipment’s powerful magnets.

This discussion is intended to provide pet and other animal owners with points of discussion they can have with their animal’s health care provider. Before any medical procedure, it’s important to understand the details about your pet’s treatment.