Evaluation of MRI issues at 3-Tesla for a hospital identification (ID) wristband.

BACKGROUND AND PURPOSE: A recent report suggested that a serious burn injury was due to the presence of the identification (ID) wristband. As such, in lieu of removing or padding hospital ID wristbands in all patients prior to magnetic resonance imaging (MRI), testing may be performed to characterize risks for ID wristbands. Therefore, the purpose of this investigation was to evaluate the magnetic field interactions, heating and artifacts at 3 T for a hospital ID wristband. MATERIALS AND METHODS: Standardized test methods were used to evaluate magnetic field interactions, MRI-related heating, and artifacts at 3 T for a hospital ID wristband. RESULTS: There were no magnetic field interactions. MRI-related heating evaluated at a relatively high, MR system-reported, whole body-averaged specific absorption rate (2.9 W/kg) did not increase above the background level. The artifacts related to the ink used for printing were "small" for one toner and "large" for the other in relation to the dimensions of the printing. CONCLUSIONS: Based on the tests performed, this particular hospital ID wristband is considered MR safe and will not pose a hazard to a patient undergoing an MRI examination. Importantly, it is not necessary to remove this item for a patient referred for MRI.

Assessment of MRI issues for a 3-T "immune" programmable CSF shunt valve.

OBJECTIVE: A newly developed CSF shunt valve that incorporates a magnetically adjustable mechanism designed to resist unintended setting changes was evaluated for problems during 3-T MRI. MATERIALS AND METHODS: Standardized protocols were used to assess magnetic field interactions, MRI-related heating, artifacts, and functional changes related to multiple exposures and various MRI conditions in nine different samples at 3 T. RESULTS: The magnetic field interactions were not excessive. MRI-related heating, which was studied at a relatively high, MRI system-reported whole body-averaged specific absorption rate (2.9 W/kg), was at a level that should not pose a hazard to a patient. Although artifacts were large in relation to the dimensions of this programmable CSF shunt valve, the results were consistent with similar devices containing permanent magnets. Multiple exposures and various MRI conditions at 3 T did not damage or affect the functional aspects of the devices, and no unintentional changes to the valve setting were observed. CONCLUSION: In consideration of the test results, this new programmable CSF shunt valve is not adversely affected by the 3-T MRI environment and is acceptable for a patient undergoing MRI at 3 T or less when specific guidelines are followed, including verifying the valve setting according to manufacturer recommendations immediately after the MRI procedure.