LAUSR

Background Little is known about brain temperature of neonates during MRI. Brain temperature can be estimated non-invasively with proton Magnetic Resonance Spectroscopy ( 1 H-MRS), but the most accurate 1 H-MRS method has not yet been determined. The primary aim was to estimate brain temperature using 1 H-MRS in infants with neonatal encephalopathy (NE) following perinatal asphyxia. The secondary aim was to compare brain temperature during MRI with rectal temperatures before and after MRI. Methods In this retrospective study, brain temperature in 36 (near-)term infants with NE was estimated using short (36 ms) and long (288 ms) echo time (TE) 1 H-MRS. Brain temperature was calculated using two different formulas: formula of Wu et al. and a formula based on phantom calibration. The methods were compared. Rectal temperatures were collected <3 hours before and after MRI. Results Brain temperatures calculated with the formula of Wu et al. and the calibrated formula were similar as well as brain temperatures derived from short and long TE 1 H-MRS. Rectal temperature did not differ before and after MRI. Conclusions Brain temperature can be measured using 1 H-MRS in daily clinical practice using the formula of Wu et al. with both short and long TE 1 H-MRS. Brain temperature remained within physiological range during MRI.