Kim Annink

52 Chapter 3 with HIE (10,24,25). More advanced MRI studies have identified cerebellar injury in HIE using diffusion tensor imaging (DTI) in the first month after birth. Also during follow-up, between 5-19 months, atrophy of the vermis was seen in children with perinatal HIE on conventional imaging (21,24). Only few postmortem histopathological studies have been performed, which all showed extensive cerebellar injury in infants with severe HIE (9,12,25). Especially PCs appear to be vulnerable to hypoxia, which leads to altered morphology or necrosis of these cells following perinatal hypoxia (13,26,27). Also the cerebellar nuclei, e.g. DN, are vulnerable and this is probably important for cerebellar functioning, since the connections between the cerebellar hemispheres and cerebral cortex converge through these nuclei (28) There seems to be a discrepancy in cerebellar injury in infants with HIE based on MRI and histology. It is important to elucidate whether DWI can reliably diagnose cerebellar injury in infants with HIE, because cerebellar injury might be associated with behavioral and cognitive problems. Therefore, the primary aim of this study was to investigate the correlation between the cerebellar ADC values in the vermis, DN and cerebellar hemispheres on DWI and the extent of histological cerebellar injury (cell death and inflammation) in infants with HIE. The secondary aim was to compare ADC values in the cerebellum of infants with HIE to neonates without brain injury. METHODS Study population In this retrospective study, we included (near-)term born neonates diagnosed with HIE, who died in the neonatal period and of whom histological material was available and underwent an antemortem DWI of the brain. All infants had to fulfill the therapeutic hypothermia inclusion criteria, although half of them were born before therapeutic hypothermia became standard of care in 2008 (1). Exclusion criteria were a gestational age <36 weeks, suspected genetic abnormalities, absence/poor quality of histological material of the cerebellum or absence/poor quality of the DWI scan. For the analysis of the DWI scans, we also included a group of neonates with congenital non-cardiac anomalies, without underlying syndromes, with a