Safety of human MRI at static fields above the FDA 8T guideline: Sodium imaging at 9.4T does not affect vital signs or cognitive ability

Abstract

Purpose To assess whether exposure to a 9.4T static magnetic field during sodium imaging at 105.92 MHz affects human vital signs and cognitive function. Materials and Methods Measurements of human vital signs and cognitive ability made before and after exposure to a 9.4T MR scanner and a mock scanner with no magnetic field are compared using a protocol approved by the U.S. Food and Drug Administration (FDA). Results Exposure to a 9.4T static magnetic field during sodium imaging did not result in a statistically significant change in the vital signs or cognitive ability of healthy normal volunteers. Conclusion Vital sign and cognitive ability measurements made before and after sodium imaging at 9.4T suggest that performing human MRI at 105.92 MHz in a 9.4T static magnetic field does not pose a health risk. J. Magn. Reson. Imaging 2007;26:1222–1227.