Kim Annink

59 Cerebellar injury in HIE: MRI versus histopathology Figure 3: Mean ADC values in infants with HIE (n=33) and controls (n=22) in the vermis (A) and DN (B). Histopathology The count of normal PCs per 1000 µm and the percentage of normal PCs were similar in the anterior, posterior and flocculonodular lobe of the vermis (p=0.21) and in the anterior, posterior and flocculonodular lobe of the cerebellar hemispheres (p=0.75). There was no correlation between the timing of death and number of normal PCs per 1000µm (r=0.08, p=0.67) and percentage of normal PCs (r=0.07, p=0.68). The median histological cytotoxic edema score was 1 (IQR 0-2) in the cerebellar hemispheres, 1.5 (IQR 1-2) in the DN and 2 (IQR 1-2) in the vermis. There were no differences in number and percentage of normal PCs between infants with no, mild, moderate and severe cytotoxic edema in the vermis and cerebellar hemispheres. In the DN, the number of normal neurons (p=0.001) and percentage of normal neurons (p=0.01) were lower in case of more severe cytotoxic edema. The postnatal age of death was not significantly different between infants with no, mild, moderate and severe cytotoxic edema based on the H&E stained slices. The median CD68 score in the cerebellar hemispheres was 2 (IQR 2-3) and the median HLA-DR score 1 (IQR 0-3). In the vermis, the median CD68 score was 2 (IQR 2-3) and HLA-DR score 2 (IQR 0-3). In the DN the median CD68 score was 2 (IQR 0-3) and HLA-DR score 0 (IQR 0-3). The count of normal PCs per 1000 µm and percentage of normal PCs in the cerebellar hemispheres were comparable between the HLA-DR and CD68 categories in the cerebellar hemispheres. The same applied to the PCs in the vermis and the neurons in the DN. Infants with HIE that had more activation of microglia and macrophages did not have more PC injury compared to infants with HIE with less activation. 3