To determine temperature changes caused by a magnetic resonance imaging (MRI) of the brain with a head coil, body and skin temperatures in 35 patients immediately before and after clinical MRI were measured.
Exposure duration: 15 min
|Exposure duration||15 min|
|Additional info||Conventional RF pulse sequence was used: Spin echo, sagittal plane, TR= 600, TE= 25, acquisition matrix= 128 x 256, slice thickness= 10 mm, average number of slices 20, average imaging time= 2:40 min; Spin echo, axial plane , TR= 2000, TE= 30 and 60, acquisition matrix= 256 x 256, slice thickness= 5 mm, average number of slices 40, average imaging time= 8:40 min.|
|SAR||2.54 mW/g||-||cf. remarks||cf. remarks||local SAR|
|SAR||60 µW/g||mean||estimated||whole body||-|
|magnetic flux density||1.5 T||-||-||-||-|
The average body temperature was 36.6 +/- 0.2°C before MRI and 36.6 +/- 0.2°C afterward. The average forehead skin temperature increased from 32.6 +/- 0.6 to 32.8 +/- 0.5°C. The average outer canthus skin temperature increased from 32.1 +/- 0.6 to 32.7 +/- 0.6 after MRI. The highest skin temperature recorded was 34.2°C. The largest temperature change was 2.1°C. There were no statistically significant changes in the average skin temperature of the upper arm and hand. There was a statistically significant decrease in the average heart rate and in the average systolic and diastolic blood pressures. The authors conclude that patients undergoing MRI of the brain with a head coil at the radiofrequency exposure studied experience no significant changes in average body temperature and statistically significant increases in local skin temperature. The observed elevations in skin temperatures were physiologically trivial.