> because the sensor needle goes through the skin it must be replaced pretty regularly

I am an MRI radiographer and get patients to take these off for their scans.

According to the link below [1] they are good for 7 days. They aren’t cheap and removing them does cause some friction so I try tie the MRI scan up with a pending monitor change and quiz diabetic patients about them at booking.

Some have gone into the scanner by accident (patients not declaring them) and they seem to survive but I emphasise that the results might not be accurate afterwards.

[1] https://www.diabeticwarehouse.org/products/dexcom-g4-and-g5-...