MRI Safety and VNS: Our Patients are Misinformed

September 3, 2014

Patients are not given enough information about their implants and MRI safety.

In my time as an MRI technologist in the Los Angeles area, I have come across many patients who have very little to no knowledge concerning the safety of their implant device. It always makes me wonder, how can this be? Especially when you have a vagus nerve stimulator (VNS). A VNS is a neurostimulator; The MRI safety warning labels posted for MR scan rooms state ‘No pacemakers or neurostimulators.’ This information is not labeled on the information card or relayed to the patient. It makes me question the healthcare provider who recommends this implant device. What information are they providing to the patient, if any? The lack of information about potential risks given to the patient, along with warnings listed on the patient information card is troubling.

As part of our patient screening, I use to check the MRI safety of many devices, I also check the information provided by the manufacturer. I'm especially concerned regarding the information provided about MRI safety of the VNS implant. The current information and articles provided by Cyberonics and the FDA state it's safe to obtain an MRI with this implant. On, the VNS implant is listed as MRI Conditional 5. At the bottom of the page there is a reference to "contact the respective manufacturer in order to obta[[{"type":"media","view_mode":"media_crop","fid":"27463","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_7834333725402","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"2685","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 222px; width: 150px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":" ","typeof":"foaf:Image"}}]]in the latest safety information to ensure patient safety."

After reading the Cyberonics Manual "MRI with the VNS Therapy System," for healthcare professionals (which is 74 pages long) on page 8, in section 2.4 is: VNS Magnet Mode Activation: "Failure to program the Magnet Mode output to 0 mA may cause Magnet Mode activation by the MRI magnets leading to undesired stimulation...Magnet Mode activation is a frequent occurrence near MR systems. For this reason, the VNS Therapy System Normal Mode output currents should be programmed to 0 mA before patient entry into the MR system room." I think this information should be included on the Cyberonics patient information card given to the patient. Possibly worded in layman’s terms... “electrical current of the implant must be turned off before entry into the MR system room” or “contact your doctor before having an MRI.” Similar to the pertinent information that is listed on a stent card. Are patients informed of the extreme caution of this implanted device presurgery and postsurgery? Not only just turning off the pulse generator, the leads that are attached to the vagus nerve can also cause serious injury to the patient.

I have read blogs from patients with VNS implants who have expressed the same concern and frustration of the main point: the lack of information given to them. From my viewpoint, these manufacturers push to advertise FDA approval and so-called “safety" to sell their product. Then patients are left to read the 74 page manual for the long list of complications and side effects. When educating patients on their implant, the safety cautions should be of the upmost concern, not the selling of the product.