Background <p>Elevated bilirubin concentrations can precipitate acute bilirubin encephalopathy and kernicterus. Furthermore, neonatal hyperbilirubinemia may compromise cerebrovascular pressure autoregulation, subsequently triggering neurological damage in neonates.</p> Objective <p>This study aimed to quantify cerebral blood flow changes in neonates with hyperbilirubinemia, revealing areas of brain that are vulnerable to the elevated bilirubin.</p> Materials and methods <p>Thirty-two neonates with hyperbilirubinemia and 30 age-sex-matched control neonates were prospectively enrolled and underwent three-dimensional (3D) T1-weighted and arterial spin labeling (ASL) scanning. Differences in regional cerebral blood flow between the two groups were assessed at voxel levels, and correlations between cerebral blood flow and serum total bilirubin were analyzed. </p> Results <p>Compared to the control group, the neonates with hyperbilirubinemia showed significantly lower regional cerebral blood flow values, mainly in the bilateral superior temporal gyrus, left middle temporal gyrus, rolandic operculum, right heschl gyrus, and thalamus (cluster-level, FWE corrected, <i>P</i>&lt;0.05). Subgroup analysis revealed a distinct threshold effect: serum total bilirubin was significantly and negatively correlated with cerebral blood flow in the high-serum total bilirubin group (<i>r</i>=-0.63, <i>P</i>=0.006), whereas no significant correlation was observed in the low-serum total bilirubin group (<i>r</i>=-0.28, <i>P</i>=0.303).</p> Conclusions <p>Our study identified alterations in regional cerebral blood flow in neonates with hyperbilirubinemia, which were associated with the serum total bilirubin levels. These findings could provide new insights into the assessment of early neurological damage caused by hyperbilirubinemia and possible therapeutic targets based on cerebral blood flow autoregulation.</p> Graphical Abstract <p></p>