Magnetic Field Influences Shunt for Hydrocephalus
Strata® valve products contain a magnet inside the valve mechanism that allows the neurosurgeon to change the pressure setting of the valve in the office. Extensive testing of the Strata valve was conducted using MRI with a static magnetic field capacity of 3.0 Tesla. Results of the testing indicate that the valve is MR Conditional. That is, exposure of the valve to MRI will not damage the valve, but may change the valve pressure setting. Therefore, immediately after MRI exposure, the valve pressure setting needs to be checked by your neurosurgeon or attending physician.
Most environmental magnetic fields encountered in everyday life will not have enough magnetic field strength to change the Strata valve’s pressure setting. Proximity to the magnetic source is the most important variable, as magnetic field strength drops off exponentially the farther one moves away from it. While it is impossible to quantify all the various magnetic fields in our environment, the vast majority will not impact the valve as long as distance from the valve implant is maintained.
The valve pressure level setting should always be verified following patient exposure to MRI or high magnetic fields. Devices known to contain magnets should be kept away from the Strata valve. Pressure settings should always be confirmed after contact with magnets. For complete safety information, including contraindications, warnings/precautions, and potential complications, see the product labeling.
Strata Valves and Magnetic Fields (PDF, 182 KB)
Influences of magnetic fields on the Strata valve