Kim Annink

231 Measurement of brain temperature using MRS This study has several limitations. The first limitation is the retrospective design in which no standard protocol was followed for rectal temperature measurements. Consequently, infants had to be excluded, because there was no rectal temperature available within 3 hours before or after the MRI, leading to a smaller sample size. With a larger sample size, it would have been more feasible to investigate the effect of brain injury on brain temperature and the effect of more risk factors such as ventilation, sedation and gestational age. Furthermore, it would have been preferable to compare rectal temperature immediately before and after the MRI using a standardized method. Nevertheless, these temperatures do represent the temperature trend of an infant. Another limitation is that the temperature probe could not be placed in the phantom for validation, but only at the surface of the phantom. However, the phantom was small, so it is most likely that the temperature inside the phantom is the same as at the surface. Furthermore, the slope of the calibration curve should remain the same, which is the most relevant. CONCLUSIONS In conclusion, this study showed that brain temperature can be measured with 1 H-MRS in daily clinical practice without calibration using the previously published formula of Wu et al . with both short and long TE 1 H-MRS. Furthermore, brain temperature remained in the physiological range during MRI in infants with neonatal encephalopathy following perinatal asphyxia and was in some infants even lower than rectal temperature before and after MRI. ACKNOWLEDGMENTS The authors thank the MR technicians, neonatologists, physician assistants and nurses for their excellent help during the MR examinations. FUNDING The PhD position of the first author Kim V. Annink is funded by the Horizon 2020 research and innovation Program of the European Union (call H2020-PHC-2015-two-stage, grant 667224, ALBINO). The PharmaCool study was funded by ZonMW (40-41500-98-9002). The 2-STEP study was funded in part by a gift of Neurophyxia (www.neurophyxia.com ). DISCLOSURES Floris Groenendaal is expert witness in cases of perinatal asphyxia. The other authors have no conflict of interest to declare. 10