Kim Annink

15 General introduction adverse neurodevelopmental outcome at two years of age (26). This technique is less commonly used in clinical practice for infants with HIE because of technical challenges, though it is predictive for outcome (26). Besides conventional T1- and T2-weighted images, DWI including ADC values and MRS, other sequences are regularly used on clinical indication, such as susceptibility weighted imaging (SWI) to detect bleedings and Diffusion Tensor Imaging (DTI) that provides additional information about white matter integrity. Magnetic Resonance Venography (MRV) can be performed to exclude sinovenous thrombosis and Magnetic Resonance Angiography (MRA) to visualize the arteries (24). There is a lot of literature about neuroimaging in infants with HIE, but the focus is mainly on supratentorial brain injury. Yet, based on histology it is known that the cerebellum is very vulnerable to hypoxic injury (27). Moreover, we know from preterm born infants that cerebellar injury increases the risk of cognitive and behavioral problems as autism spectrum disorders significantly (28). Chapter two and three describe cerebellar injury in HIE. Chapter two provides insight in the histopathological pattern of cerebellar injury in HIE and chapter three in the correlation between cerebellar injury based on DWI and histopathology. Although MRI is the gold standard in neuroimaging, in some hospitals or countries MRI is not available, or if infants are clinically too unstable for transport, MRI might not be feasible (29). For those infants, cerebral ultrasound (CUS) might offer an alternative since it is an immediately available, bedside and cheaper neuroimaging modality. Additionally, CUS can be performed daily in infants with HIE which enables monitoring of evolving abnormalities. Until now, there is no standardized and validated method to assess brain injury with CUS in infants with HIE yet. Therefore in chapter four, the development and validation of a new CUS scoring system is described. Therapeutic hypothermia The only current therapy for infants with HIE to reduce brain injury is therapeutic hypothermia (1,30). Neonates are cooled to 33.5°C for 72 hours. This treatment should be started within six hours after birth, the window of therapeutic opportunity, for an optimal effect. The exact working mechanism has not yet been elucidated completely. Nevertheless, there is evidence that therapeutic hypothermia 1