Thermophysiologic and hemodynamic changes associated with clinical MR imaging at 1.5 T

Thermophysiologic and hemodynamic responses to high-field (1.5-T) MR imaging were studied in 50 patients who underwent procedures at radio frequency power deposition levels above the current recommended specific absorption rate guideline of 0.4 W/kg (range, 0.5-1.2 W/kg). Body temperature increased an average of 0.20C (range, 0.00-0.70C). Changes in skin temperatures were variable, depending on anatomic site, and ranged from 0.10 to 3.30C. The highest skin temperature recorded was 35.10C. The average heart rate and blood pressure before MR imaging were unchanged after the procedures. The observed thermophysiologic and hemodynamic effects of MR imaging at the specific absorption rates studied were well tolerated by the patients and were not considered to be deleterious