Volumetric changes in brain MRI of infants with abnormal development who had Hypoxic-ischemic Encephalopathy and underwent therapeutic hypothermia

Abstract

Abstract Background Hypoxic-ischemic encephalopathy (HIE) is a severe neonatal complication that can result in 40–60% of long-term morbidity. MRI is a noninvasive method which is usually performed before discharge to visually assess acquired cerebral lesions associated with HIE and severity of lesions possibly providing a guide for detecting adverse outcomes. This study aims to evaluate the impact of HIE on brain volume changes observed in MRI scans performed at a mean 10 days of life, which can serve as a prognostic indicator for abnormal neurodevelopmental (ND) outcomes at 18–24 months among HIE infants. Methods We retrospectively identified a cohort of HIE patients between June 2013 and March 2017. The inclusion criteria for TH were a gestational age ≥ 35 weeks, a birth weight ≥ 1,800 g, and the presence of ≥ moderate HIE. Brain MRI was performed at a mean 10 days of life and brain volumes (total brain volume, cerebral volume, cerebellar volume, brain stem volume, and ventricle volume) were measured for quantitative assessment. At 18–24 months, the infants returned for follow-up evaluations, during which their cognitive, language, and motor skills were assessed using the Bayley Scales of Infant and Toddler Development III. Results The study recruited a total of 240 infants between 2013 to 2017 for volumetric brain MRI evaluation. Among these, 83 were normal control infants, 107 were TH-treated HIE infants and 37 were HIE infants who did not receive TH due to contraindications. Clinical evaluation was further proceeded among the 107 TH-treated HIE infants. We grouped according to brain MRI findings; 33.6% (36/107) infants had normal or minimal lesions of brain MRI and 66.4% (71/107) had abnormal MRI findings. At 18–24 months, 31 of 107 infants (29.0%) had delayed neurodevelopment and 76 of 107 infants (71.0%) were normal in their neurodevelopmental stages. When comparing brain volumes between the normal control infants (n = 83) and the abnormal ND group at the corrected 18–24 months of age (n = 31) in the 107 TH -treated HIE group, abnormal ND group exhibited a significant reduction in brain stem volume and larger ventricular volume (p < 0.001). This observation was consistent when we regrouped the HIE infants according to severe brain MRI group who did not receive TH due to contraindications. Conclusion In addition to location of brain injury in MRI assessment, brain stem volume reduction accompanied by larger ventricular volume in HIE infants may serve as a biomarker indicating severe HIE and adverse long-term neurodevelopmental outcomes among HIE infants who were treated with TH.