Maayke Hunfeld

160 Chapter 5 variables and ancillary tests) should be taken into account when determining outcome in a child post-OHCA with focal injury on brain MRI. Similarly, the associations we found between bilateral brain injury in various brain areas and poor neurological outcome or death, are not by themselves suitable for outcome prediction in the individual patient. However, the associations are strong, and are promising for possible implication in future multi-variable prediction models, especially T2- and DWI/ADC-abnormalities. Indeed, none of the children demonstrated brain injury on T1-weighted images only, without corresponding T2 abnormalities. Though most of the abnormalities were detected both on T2 and on DWI/ADC, some abnormalities were only detectable either on T2-weighted images or on DWI/ADC. This implicates that especially T2-weighted images and DWI/ADC are mandatory and complementary when assessing post-hypoxic brain injury in children after OHCA. A strength of our study is the longitudinal follow-up interval up to 2 years after OHCA. By including only OHCA children, we created a homogeneous cohort. All brain MRIs were performed within 1 week post-OHCA. Furthermore, 2 experienced and blinded neuroradiologists assessed all brain MRI studies. We have attempted to predict neurological outcome without using other OHCA variables. However, due to a small sample size and the use of a crude outcome scale (PCPC), we think that predicting outcome solely based on a normal MRI or MRI with extensive brain injury is inappropriate for application in clinical practice. According to the scientific statement from Topjian et al. (2019) multiple factors and ancillary tests (neurological exam, EEG) should be considered when predicting outcome in children after OHCA (8). As to limitations, until 2017, brain MRIs were only performed at the discretion of the treating clinician and not as part of standard care. The children who did not receive brain MRI were more severely affected. Therefore, the treating physician probably determined that a brainMRI was not contributing to the decision to WLST (table 1.), creating a selection bias. Self-fulfilling prophecy is unavoidable, clinicians have potentially used the brain MRI findings for decision making to WLST. We designed a scoring system based on existing literature, however, this system has not been validated yet. To improve the prognostic accuracy of brain MRI (which affected brain areas are specifically associated with outcome) and to ensure our findings are correct, larger sample sizes are needed. Additionally, brain MRI findings should not only be correlated with survival and PCPC, but it should also include other outcome domains: neurocognitive function, physical functioning and basic daily life skills (according to P-COSCA) (23). This can be achieved by international collaboration, like the Pediatric Resuscitation Quality Collaborative (PediRES-Q) (24). A scoring system and registry should be designed and validated to report brain MRIs in the same way. Preferably,