Semi-Quantitative Analysis of Brain MR Imaging in 76 Cases of Neonatal Indirect Hyperbilirubinemia

Background: Neonatal hyperbilirubinemia is indeed common. However, severe nerve injuries and bilirubin encephalopathy are rare and only occur in the unusual cases of extreme hyperbilirubinemia. Objectives: To investigate brain magnetic resonance imaging (MRI) changes and their correlations with perinatal predisposing factors in neonates with indirect hyperbilirubinemia, via regions of interest (ROIs) analysis. Methods: Seventy-six neonates with a gestational age of ≥35 weeks diagnosed with neonatal indirect hyperbilirubinemia or bilirubin encephalopathy all underwent brain MRI during hospitalization. Depending on peak total serum bilirubin (TSB), they were assigned to group A (<221 μmol/L), B (≥221 μmol/L <342 μmol/L), C (≥42 μmol/L <428 μmol/L), or D (≥428 μmol/L). The globus pallidus and the white matter around the anterior horn of the lateral ventricle and posterior horn of the lateral ventricle were selected as the ROIs. Average optical densities (AODs) of the ROIs and the cerebrospinal fluid region were measured. The ratio between the AODs was designated as the relative optical density (ROD), and used to determine relative signal intensity. Results: RODs of the globus pallidus were significantly lower in group D than in all other groups. TSB and the ratio of TSB to serum albumin concentration (B/A) was significantly negatively correlated with ROD in theglobus pallidus. Corrected age was significantly negatively correlated with the ROD of the ROIs. Conclusions: Semi-quantitative image analysis is a feasible method to assess conventional brain MRI for neonatal indirect hyperbilirubinemia. The signal intensity of the globus pallidus in T1-weighted images was significantly correlated with TSB level and B/A.