Effect of static magnetic field exposure of up to 8 Tesla on sequential human vital sign measurements

Purpose To determine if increasing static magnetic field strength exposures up to 8 Tesla (T) affect vital signs or electrocardiograms (ECGs) in normal human volunteers. Materials and Methods We studied 25 normal subjects, consisting of 19 men and six women, ages 24–53 years. The vital signs and ECGs of the subjects were measured 14 times inside and outside the magnetic field. This included the heart rate, respiratory rate, systolic and diastolic blood pressures, finger pulse oxygenation levels, core body temperature via the external auditory canal temperature, and fiber optic core body sublingual temperatures. Inside the magnetic field the vital signs were measured sequentially at field strengths of 8, 6, 4.5, 3, and 1.5 T. Results The only statistically significant effect of magnetic field strength was observed with systolic blood pressure. An average increase of 3.6 mm Hg in systolic blood pressure was seen with 8 T exposure. ECG rhythm strip analysis demonstrated no significant changes post‐exposure. Conclusions Normal subjects exposed to varying magnetic field strengths of up to 8 T demonstrated no clinically significant changes in vital signs. Transient ECG artifacts were noted to increase with the field strength. J. Magn. Reson. Imaging 2003;18:346–352. © 2003 Wiley‐Liss, Inc.