MRI Score Ability to Detect Abnormalities in Mild Hypoxic-Ischemic Encephalopathy

Abstract

Background: Magnetic resonance imaging (MRI) scores have been well validated in moderate/severe hypoxic-ischemic encephalopathy (HIE). Infants with mild HIE can have different patterns of injury, yet different scores have not been compared in this group of infants. Our objective was to compare the ability of three = MRI scores to detect abnormalities in infants with mild HIE, and infants with moderate/severe HIE were included for comparison.

Methods: This is a single-center prospective cohort study of infants ≥36 weeks' gestation with HIE born at a level III neonatal intensive care unit from 2017 to 2019. All infants with HIE underwent an MRI, but only infants with moderate/severe HIE underwent therapeutic hypothermia. At least two experienced MRI readers who were unaware of all clinical variables independently assigned three scores (Barkovich, NICHD NRN, and Weeke).

Results: A total of 42 newborns with varying HIE severity underwent MRI on day five of life. In the overall cohort, abnormalities were reported in three (7%) infants using the Barkovich, in 10 (24%) using the NICHD NRN, and in 24 (57%) using the Weeke score. Agreement was excellent for each score: Barkovich score (k = 1.0), NICHD NRN (k = 0.92), and Weeke score (k = 0.9).

Conclusions: Subtle injury due to mild HIE was detected with the highest frequency using the Weeke score, while inter-rater reliability was excellent for all three scores. These findings suggest that infants with mild HIE and subtle MRI abnormalities may benefit from detailed scoring systems, which is important for studies investigating the benefit of hypothermia in mild HIE.

Keywords: Barkovich score; Magnetic resonance imaging (MRI) scores; Mild hypoxic-ischemic encephalopathy (HIE); NICHD NRN score; Neonatal encephalopathy; Neonatal magnetic resonance imaging (MRI); Weeke score.

FIGURE 1.

Magnetic resonance imaging (MRI) patterns of brain injury in HIE. MRI examples of abnormalities (marked by white arrows) as detected by the different scores are highlighted. (A and B) Extensive abnormal signal intensity in the bilateral basal ganglia and bilateral thalami on axial T1 and T2. This pattern indicates high severity of injury identified on all three scores. (C and D) Multiple unilateral punctate white matter lesions on axial diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC). Punctate white matter lesions are not specifically included in the Barkovich score. (E and F) Multiple bilateral punctate white matter lesions with involvement of the corpus callosum on axial DWI and ADC. The punctate white matter lesions are identified by both the NICHD NRN score and the Weeke score, whereas only the Weeke score includes additional severity scoring specific for injury to the corpus callosum. (G-I) Focal cerebellar hemorrhage on axial T1- and T2-weighted imaging and susceptibility-weighted imaging (SWI). Hemorrhage is only included by the Weeke score.

FIGURE 2.

Correlation of magnetic resonance imaging (MRI) scores. The cutoff line highlights that the Weeke score allowed for reporting of additional abnormalities on MRI, which were not scored by either the Barkovich or the National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) score.