Physiologic responses to an MR imaging procedure performed at a specific absorption rate of 6.0 W/kg.

Abstract

To assess the physiologic responses to a magnetic resonance (MR) procedure performed at a whole-body-averaged specific absorption rate (SAR) of 6.0 W/kg. Tympanic membrane temperature, skin temperature at seven sites, heart rate, blood pressure, oxygen saturation, and cutaneous blood flow in six volunteers were assessed before, for 16 minutes during, and immediately after MR imaging performed at 1.5 T, 64 MHz. Statistically significant (P < .05) increases in temperature of the tympanic membrane and the skin of the chest, abdomen, upper arm, hand, and thigh and in heart rate and cutaneous blood flow were associated with exposure to high SAR. None of these physiologic changes, however, were considered deleterious to the study subjects. MR imaging procedures performed at the high SAR studied can be tolerated by persons with normal thermoregulatory function.