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Brain injury following mild hypoxic-ischemic encephalopathy in neonates–Ten-year experience in a tertiary perinatal center



We aimed to evaluate abnormal magnetic resonance imaging (MRI) findings in neonates with mild hypoxic-ischemic encephalopathy (HIE).

Study design

This was a single-center, retrospective study of mild HIE conducted from 2011 to 2020. Almost all neonates with mild HIE received management targeted to a temperature of 36 ± 0.5°C for 72 h and underwent MRI (135 of 145). We evaluated medical records and assessed amplitude-integrated electroencephalography (aEEG).


All participants survived until discharge. Abnormal MRI findings were present in 23/135 (17%) neonates. The normal versus abnormal MRI-finding groups had similar characteristics, except discontinuous aEEG patterns (p = 0.002) and inotropic drugs (p = 0.035). Regression analyses showed discontinuous aEEG patterns (odds ratio = 19.3, 95% confidence interval=1.88–197, p = 0.013) being associated with higher odds of abnormal MRI findings.


Our study suggests that a discontinuous aEEG pattern is associated with abnormal MRI findings and can be used to discuss the definition of mild HIE.

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Fig. 1: Flow diagram of participant selection.

Data availability

The data supporting the findings of this study are available from the corresponding author, T. I., upon reasonable request.


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Author information

Authors and Affiliations



TI conceptualized the study, and MS and MK devised the methodology. KK provided feedback to refine the methodology and analysis. TI, WS, CK, and MK collected the clinical data. TI drafted the manuscript, and MS reviewed the manuscript and provided critical feedback.

Corresponding author

Correspondence to Toshiyuki Imanishi.

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Competing interests

The authors declare no competing interests.

Ethics approval and consent to participate

This study was approved by the Institutional Research Ethics Board of Saitama Children’s Medical Center (approval number: 2021-03-024). Parental consent was not required because of the retrospective nature of this study.

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Imanishi, T., Shimizu, M., Sumiya, W. et al. Brain injury following mild hypoxic-ischemic encephalopathy in neonates–Ten-year experience in a tertiary perinatal center. J Perinatol 42, 1630–1636 (2022).

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