Abstract
BACKGROUND: No previous study has investigated the relationship between middle cerebral artery (MCA) flow velocity and the severity of hypoxic ischemic encephalopathy (HIE) evaluated by magnetic resonance imaging (MRI). The aim of this study was to assess the correlation between cerebral blood flow as assessed by transcranial Doppler sonography and the severity of MRI brain injury in asphyxiated neonates with clinical HIE who received therapeutic hypothermia. METHODS: This retrospective cohort study was conducted in the neonatal intensive care unit at Chang Gung Memorial Hospital between April 2011 and May 2014. All neonates with HIE who received therapeutic hypothermia, transcranial Doppler examinations, and brain MRI were eligible. Brain MRI was performed at 11 days of age (interquartile range: 8.5-15 days) and the severity of MRI brain injuries was evaluated using the MR scoring system proposed by Barkovich et al. Serial transcranial Doppler examinations were performed in pre-hypothermia, hypothermia, and post-hypothermia phases. RESULTS: Twenty-six neonates met the eligibility criteria for this study. Neonates with an abnormal MCA mean flow velocity (MFV) during the hypothermia phase had a higher risk of brain MRI abnormalities (77.8% vs. 22.2%, p = 0.017) and neonates with abnormal high MFV of MCA had higher MR scores of basal ganglia (p = 0.022). However, there were no statistical differences between abnormal MFV of MCA and brain MRI abnormalities during pre- and post-hypothermia phases. CONCLUSIONS: During therapeutic hypothermia, mean cerebral blood flow velocity of the MCA was associated with the severity of MRI brain injury in the neonates with clinical HIE.