Temperature, heart rate, and blood pressure changes associated with clinical MR imaging at 1.5 T

Temperature, heart rate, and blood pressure responses to high-field-strength magnetic resonance (MR) imaging were studied in 50 patients who underwent procedures at exposures to radiofrequency radiation above the present recommended whole-body average specific absorption rate (SAR) of 0.4 W/kg. Body temperature significantly increased an average of 0.2 degrees C. The highest body temperature recorded after MR imaging was 37.5 degrees C. There was no significant correlation between the change (before and after imaging) in body temperature and whole-body average SARs. Changes in skin temperatures were variable, depending on anatomic site. The largest change was 3.5 degrees C, and the highest skin temperature recorded after imaging was 35.1 degrees C. There was a modest correlation between the change in skin temperatures and whole-body average SARs. Average heart rate and average mean blood pressure measured immediately before imaging were not significantly different afterward. High-field-strength MR imaging at the whole-body average SARs of 0.42-1.2 W/kg studied was not associated with any temperature- or hemodynamic-related deleterious effects.