Ultrasound and Photoacoustic Imaging of Hydrocephalus in Pediatric Patients

The goal of this study is to out find out the capabilities and limitations of the combined photoacoustic and ultrasound (PAUS) imaging device for diagnosing hydrocephalus in children. The main questions it aims to answer are: * can PAUS imaging allow for new and better ways to rapidly diagnose hydrocephalus? * Can PAUS imaging be used to confirm that treatments for hydrocephalus are working? PAUS imaging has been FDA approved for other medical conditions, but this is the first study to evaluate it for hydrocephalus detection. Participants will undergo imaging through the anterior fontanelle with the dual-mode PAUS imaging device. Each imaging session will take about 30 to 60 minutes. These sessions will take place once before and once after hydrocephalus treatment, as the participant is willing. In some cases, if a patient is having cerebrospinal fluid removed at the bedside, an additional imaging session will occur to monitor the procedure in real-time, if the participant is willing.

Inclusion Criteria: * Diagnosis of hydrocephalus by a neurosurgeon * Age ≤ 3 years * Admitted to Penn State Health Children's Hospital with plans for definitive hydrocephalus treatment while inpatient, including shunt placement surgery, endoscopic third ventriculostomy, shunt revision, external ventricular drain placement. Exclusion Criteria: * Age \> 3 years * No open anterior fontanelle or fontanelle is obstructed for clinical purposes * Too unstable to undergo diagnostic testing equivalents (i.e. standard ultrasonography)