The US Food and Drug Administration (FDA) has cleared the Abbott Libre 2 and 3 continuous glucose monitoring (CGM) sensors for use during most imaging procedures, including MRI under certain specifications.

“Abbott has rigorously tested the sensors in the FreeStyle Libre 2 and 3 systems to ensure they remain effective after radiological procedures. This testing led the FDA to remove the contraindication requirement without any changes to the sensor,” the company said in a statement.

The sensors can now also be worn during CT or X-ray procedures. Previously, they were contraindicated for use during MRI, CT and high-frequency electrical heat (diathermy) treatment due to concerns that exposure could damage the sensor and could lead to incorrect readings. These contraindications remain valid for the older FreeStyle Libre 14-Day Rapid Blood Glucose Monitoring System, and the diathermy contraindication remains for all models.

The Libre 2 and 3 labels now say that patients can safely undergo a 1.5T or 3T field strength MRI exam while wearing the sensor, under specific conditions listed. Scanning between pelvis and sternum (3T scans) should be limited to a maximum of 12 minutes, with a 2-minute cool-down period between scans. All other areas (1.5T scans) can be scanned for up to 1 hour continuously without a cool down period.

“MRI protocols are evolving and can vary, so it’s best for people with diabetes to talk to their healthcare provider or radiology department before an MRI scan to make sure conditions meet safety requirements as they are stated in the label,” said Anila Bindal, MD, associate medical director for the Abbott Diabetes Care business Medscape Medical News.

Patients should also be instructed to leave their phones and sensor reader outside the exam room. Sensor readings may be inaccurate during the MRI, but should return completely to normal after 1 hour, according to the label.

Regarding the current Dexcom G7 CGM system, those instructions say: “Do not wear any component of the Dexcom G7 CGM system during (MRI) or (diathermy) treatment. However, it is safe to have a CT scan if you hold the sensor out of the scanned area and cover the sensor with a lead apron during the scan.”

Miriam E. Tucker is a freelance journalist based in the Washington, DC area. She is a regular contributor to Medscape Medical News, and other work appears in the Washington Post, NPR’s Shots blog, and Diatribe. She’s on X: @MiriamETucker.