A Study of Temporal Evolution of Morphological Brain Changes on Conventional MRI Sequences and Brain Metabolites on MR Spectroscopy in Infants with Neonatal Hypoxic Ischemic Encephalopathy

Abstract

Magnetic resonance imaging (MRI) and Proton magnetic resonance spectroscopy (1HMRS) plays an important role in assessment and prognostication of the brain damage due to perinatal hypoxic-ischemic encephalopathy (HIE). Serial imaging is superior and is more useful especially in the prognostication. The aim of the present study was to assess the Temporal evolution of morphological brain changes on conventional MR imaging sequences and brain metabolites on MRS in deep gray matter as early as possible after birth, their status on follow up MRI scan in first 6 months of life. A prospective observational study was performed between October 2020 and September 2021. 31 full-term neonates with HIE, were included. Two sequential MR studies were performed; a conventional MR imaging, and proton MR spectroscopy for observation in the deep gray matter. Morphological brain changes were studied in the form of MRI scoring system. Followup with clinical examination for neurodevelopmental delay was done in our pediatric neurology clinic at 6 to 7 months of age. Mean MRI score in the first scan was found out to be 5.58 and in the second scan it was around 2.25. 30 subjects out of 31 showed lactate peak in the first scan and on followup imaging 8 out of 30 infants showed persistence of lactate peak (P value  < 0.0001), 27 (87.1 %) out of 31 subjects showed increase in NAA/Cr ratio on followup scan and 4 (12.9%) subjects showed decrease in NAA/Cr ratio. 5 out of 31 infants showed developmental delay, one infant expired and 25 infants (80 %) had no significant developmental delay. In conclusion there is significant correlation between persistence of lactate peak, decrease in NAA/Cr ratio and increased MRI score with neurodevelopmental delay.

Keywords: Hypoxic-ischemic encephalopathy, Magentic resonance spectroscopy, Lactate peak, NAA/Cr ratio, neurodevelopmental delay, serial MRI.