Kim Annink

116 Chapter 6 and neurodevelopmental testing impossible and contraindications for MRI, such as braces, a pacemaker or claustrophobia. Children born before therapeutic hypothermia became standard of care in 2008, who met the therapeutic hypothermia criteria, were included in the non- hypothermia group (non-HT group). Children that were treated with hypothermia were included in the hypothermia group (HT group). Written parental informed consent and child assent was obtained for all study participants. The medical ethical committee of the UMC Utrecht approved the study (NL44807.041.14) Neonatal clinical and MRI data Baseline characteristics and standard follow-up data were retrospectively collected from the electronic patient files, as well as the neonatal MRI scans if these were available. MRI scans were conducted on a 1.5Tesla (T) in all infants in the non-HT group and partly in the HT group or 3.0T MR scan from 2009 onwards in the HT group (Philips Healthcare, Best, the Netherlands). The scan protocols included diffusion Weighted Imaging (DWI) (slice thickness=4mm, b-values of 0 and 1000s/ mm 2 with acquisitive matrix of 128x77 at 1.5T and of 0 and 800s/mm 2 with acquisitive matrix of 112x89 at 3.0T), Inversion recovery or T1-weighted imaging (1.5T Inversion Recovery: slice thickness=2mm, TE=4147ms, TI=600ms, TR=30ms, acquisitive matrix of 256x153; 3.0T T1: slice thickness=2mm, TE=9.4ms, TR=4.6ms, acquisitive matrix of 192x152) and T2-weighted imaging (1.5T: slice thickness=2mm, TE=7565ms, TR=150ms, acquisitive matrix 256x184; 3.0T: slice thickness=2mm, TE=6293ms, TR=120ms, acquisitive matrix 336x234). When available, the neonatal MRI scans were retrospectively scored according to Weeke et al. by two raters who were blinded to childhood outcome (12). This MRI score includes multiple items such as diffusion restriction of the thalamus and hippocampus. Injury to the MB on the neonatal MRI was assessed separately. MB were classified as normal, equivocal or abnormal based on neonatal T1- and T2- weighted sequences and DWI. The definition of normal was a similar signal intensity of the MB as the surrounding tissue and no swelling. The MB were scored “equivocal” if there appeared to be a higher signal intensity of the mammillary bodies on the T2-weighted image or a low signal on T1-weighted imaging but without swelling, so