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 rigorously tested its FreeStyle Libre 2 and 3 systems sensors to ensure they remain effective after radiologic procedures. This testing led the FDA to clear the removal of the contraindication requirement, with no changes made to the sensor," the company said in a statement.
The sensors may also now 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 concern that the exposure could potentially damage the sensor and lead to incorrect readings. Those contraindications remain in place for the older FreeStyle Libre 14-day Flash 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 listed conditions. Scanning between the pelvis and sternum (3T scanners) should be limited to 12 minutes maximum with a cooling period of 2 minutes between scans. All other areas (1.5T scanners) can be scanned for up to 1 hour continuously without a cooling period.
"MRI protocols are evolving and can vary, so it's best if people with diabetes speak to their healthcare provider or the radiology department prior to an MRI scan to ensure the conditions meet the safety requirements as stated in the labeling," Anila Bindal, MD, associate medical director for Abbott Diabetes Care business, told Medscape Medical News.
Patients should also be instructed to leave their phones and the sensor reader outside the exam room. Sensor readings may be inaccurate during the MRI but should return fully back to normal after 1 hour, according to the label.
As for the current Dexcom G7 CGM system, those instructions say, "Don't wear any Dexcom G7 CGM System component during [MRI] or [diathermy] treatment. However, it's safe to have a CT scan if you keep the sensor out of the scanned area and cover the sensor with a lead apron during the scan."