Neonatal hyperbilirubinemia is a prevalent condition during the neonatal period, and in severe instances, it can result in brain damage accompanied by irreversible neurological consequences. Therefore, early detection and intervention are paramount. This research aimed to detect early-stage brain damage resulting from neonatal hyperbilirubinemia through the application of two-dimensional cranial ultrasound and microvascular blood flow (MV-Flow) imaging techniques. Clinical data, along with gray-scale and microvascular ultrasound images of the basal ganglia, were collected from 85 neonates (hyperbilirubinemia group vs. non-hyperbilirubinemia group: 51 vs. 34). The Globus Pallidus to Putamen (G/P) ratio and the vascular index (VI