Kim Annink

100 Chapter 5 The total ICV was similar in the three groups (controls: 1498ml±179ml; HIE1: 1456±144ml; HIE2: 1432±205ml, p=1.000, Figure 2B). When correcting for ICV, differences in the percentage hippocampus/ICV were observed between the three groups, with smaller volumes in HIE (controls 0.58%±0.05 HIE1: 0.56%±0.06; HIE2: 0.53%±0.07; p=0.012, Figure 2C). Again, HIE2 and controls differed significantly in the post-hoc tests. After correcting for ICV, the difference between HIE2 and controls was 8.6%. Girls had a significantly larger percentage hippocampus/ICV compared to boys in the total group (boys: 0.55%±0.06; girls: 0.58%±0.06; p=0.012). Figure 2: Overview of hippocampal volumes in controls, HIE1 and HIE2. The total hippocam- pal volumes (A) were significantly smaller in the HIE2 group compared to controls, but the volumes of the HIE1 group were not significantly different. The total hippocampal volume as a percentage of ICV (B) was smaller in the HIE2 group compared to controls, but again the HIE1 group did not differ significantly. The intracranial volumes (C) were similar in the three groups. Multivariable linear regression with the percentage hippocampus/ICV as a dependent variable and HIE1/HIE2/control, age and sex as independent variables showed that HIE2 and sex were significantly associated with hippocampal volume. HIE2 was associated with a reduction of the percentage hippocampus/ICV of 0.054% (95%CI -0.083% - -0.025%), HIE1 with a reduction of 0.021% (95%CI -0.050%-0.008%) and being a girl with an increase of 0.035% (95%CI 0.011%-0.069%).