An insulin pump allows the replacement of slow-acting insulin for basal needs with a continuous infusion of rapid-acting insulin. By using an insulin pump, a patient can typically match the dosage of insulin to lifestyle and activities, rather than adjusting those to the body’s response to insulin injections. The advantages of using an insulin pump include the fact that an insulin pump replaces the need for periodic injections by delivering rapid-acting insulin continuously throughout the day via a catheter. It greatly simplifies the management of diabetes.
There are two basic types of insulin pumps, one is an external device and the other is implanted. Both types currently pose hazards to patients referred for MRI procedures. For an external insulin pump, it may simply need to be removed and kept out of the MR environment to ensure there is no adverse impact on the device’s functionality.
The information below provides MRI labeling for several of the most commonly used insulin pumps.
This MRI information pertains to the following insulin pumps from Animas, a Johnson & Johnson company:
- Animas 2020 Insulin Pump
- IR Animas 1200
- IR 1000 Insulin Pump
- IR 1100 Insulin Pump
- IR 1200 Insulin Pump
Each of the insulin pumps listed above should be kept from exposure to very strong electromagnetic fields, such as MRIs, radiofrequency welders, or magnets used to pick up automobiles. Very strong magnetic fields, such as those associated with MRI, can magnetize the portion of the pump’s motor that regulates insulin delivery and thus damage the device.
For the patient: If you plan to undergo an MRI, remove the insulin pump beforehand and keep it outside of the MR room during the procedure. If the pump is accidentally allowed into the MR system room, disconnect the pump immediately and contact Animas Pump Support for important instructions.
For the Healthcare Professional: Do not bring the insulin pump near the MR system at any time. If the pump is accidentally allowed into the MR system room, disconnect the pump immediately and contact Animas Pump Support for important instructions.
Cozmo Pump, Infusion Pump
The user manual for the Cozmo Pump (Deltec, St. Paul, MN), states the following regarding MRI:
“Caution: Avoid strong electromagnetic fields, like those present with magnetic resonance imaging (MRI) and direct x-ray, as they can affect how the pump works. If you cannot avoid them, you must take the pump off.”
MiniMed 2007 Implantable Insulin Pump System
The Medtronic MiniMed 2007 Implantable Insulin Pump System (Medtronic MiniMed, Northridge, CA) may offer treatment advantages for diabetes patients who have difficulty maintaining consistent glycemic control. Patients who have not responded well to intensive insulin therapy, including multiple daily insulin injections or continuous subcutaneous insulin infusion using an external pump, may be primary candidates for the Medtronic MiniMed 2007 System. The implanted device delivers insulin into the peritoneal cavity in short, frequent bursts or pulses, similar to how pancreatic beta cells secrete insulin.
The Medtronic MiniMed 2007 Implantable Insulin Pump is designed to withstand common electrostatic and electromagnetic interference but must be removed prior to undergoing an MR procedure. Any magnetic field exceeding 600 gauss will interfere with the proper functioning of the pump for as long as the pump remains in that field. Fields much higher than that, such as those emitted by an MR system, may cause irreparable damage to the pump.
By comparison, infusion sets (MMT-11X, MMT-31X, MMT-32X, MMT-37X, MMT-39X) used with this device contain no metallic components, thus are safe to be used and can remain attached to the patient during an MR procedure. The only exceptions would be Polyfin infusion sets. Polyfin infusion sets (MMT-106 AND MMT-107, MMT-16X, MMT-30X, MMT-36X) have a surgical steel needle that remains in the subcutaneous tissue. These infusion sets should be removed prior to any MR procedure.
MiniMed Paradigm REAL-Time Insulin Pump and Continuous Glucose Monitoring System (522 and 722 Insulin Pumps)
MRI Information for Patients re: magnetic fields: Do not use pump cases that have a magnetic clasp. Do not expose your insulin pump to MRI equipment or other devices that generate very strong magnetic fields.
Magnetic fields in the immediate vicinity of such equipment can damage the part of the pump’s motor that regulates insulin delivery, possibly resulting in overdelivery and severe hypoglycemia. Your pump must be removed and kept outside the room during magnetic resonance imaging (MRI) procedures.
If your pump is inadvertently exposed to a strong magnetic field, discontinue use and contact your local help line or representative for further assistance.
The insulin pump, transmitter, and sensor must be removed prior to entering the MRI environment.
The DANA Diabecare IIS Insulin Pump and DANA Diabecare Insulin Infusion Pump (SOOIL Development, San Diego) must not be used in the presence of intense electromagnetic fields, such as those generated by certain electrically powered medical devices. The pump should be removed prior to the user having a CT scan, MRI, or x-ray. (MRI healthcare professionals are advised to contact the respective manufacturer for the latest safety information to ensure patient safety relative to use of the device during an MR procedure.)
Dr. Shellock is adjunct clinical professor of radiology and medicine at the Keck School of Medicine, University of Southern California. He is also director for MRI Studies of Biomimetic MicroElectronic Systems at the National Science Foundation, Engineering Research Center, University of Southern California.