1. Establish a reference curve for the lateral ventricular diameter of premature infants and determine the intervention threshold for hydrocephalus after hemorrhage in premature infants based on the reference curve, providing a scientific basis for optimizing clinical intervention.
2. Apply ultrasound radiomics technology to explore and formulate new standards for imaging diagnosis and treatment; By integrating metabolomics, ultrasound radiomics and clinical data, high-risk individuals for intracranial hemorrhage and their relationship with prognosis can be identified early.
3. To explore whether advancing the indication for surgical intervention of hydrocephalus in preterm infants after hemorrhage from ventricular index P97+4mm to P97 and whether repeated lumbar puncture and drainage can improve their prognosis, with the aim of clarifying the optimal timing for intervention of hydrocephalus in preterm infants after hemorrhage and optimizing the treatment methods.

Inclusion Criteria:

• Gestational age: 23+0 weeks to 36+6 weeks;
• Post-hemorrhagic hydrocephalus is confirmed by cranial ultrasound or other cranial imaging examinations.
• No cerebrospinal fluid drainage treatment was received before enrollment.

Exclusion Criteria:

• Excluding secondary IVH, including but not limited to congenital malformations, vitamin K1 deficiency, abnormal coagulation function, etc.
• Excluding hydrocephalus caused by other reasons, including but not limited to infection, congenital malformations, intracranial space-occupying lesions, etc.
• Treatment before diagnosis of hydrocephalus after intraventricular hemorrhage or suspected presence of central nervous system infection.