RESUMEN
BACKGROUND: Little is known about brain temperature of neonates during MRI. Brain temperature can be estimated non-invasively with proton Magnetic Resonance Spectroscopy (1H-MRS), but the most accurate 1H-MRS method has not yet been determined. The primary aim was to estimate brain temperature using 1H-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) 1H-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 1H-MRS. Rectal temperature did not differ before and after MRI. CONCLUSIONS: Brain temperature can be measured using 1H-MRS in daily clinical practice using the formula of Wu et al. with both short and long TE 1H-MRS. Brain temperature remained within physiological range during MRI.