Various imaging modalities are useful in confirming the diagnosis, determining the etiology of adult hydrocephalus, providing intraoperative guidance, and improving the follow-up of patients who have undergone treatment including cerebrospinal fluid (CSF) shunting or endoscopic third ventriculostomy (ETV). These include: conventional X-rays, ultrasonography, computerized axial tomography (CT), magnetic resonance imaging (MRI), and radionuclide shunt patency (SP) imaging. CT scans are performed to obtain a baseline image postoperatively to demonstrate the location of the proximal catheter in the ventricular system, the baseline size of the ventricles, and any postoperative intraventricular hemorrhage. CTs are helpful in diagnosing shunt malfunctions in younger patients. MRI provides excellent multiplanar anatomic definition of the ventricular system, subarachnoid spaces, and brain parenchyma. The SP study is a valuable tool in the diagnosis of shunt malfunction particularly in the idiopathic normal pressure hydrocephalus (iNPH) patient population.

This chapter first focuses on the ethics of animal models and then discusses the formal requirements general to any experimental model and the specific requirements for models of hydrocephalus. It also discusses the recent and current research areas in experimental hydrocephalus. Ethical standards for experimental studies involving animals are legally set by laws and regulations. Animal models resemble human disease by conditions which are genetically determined, naturally acquired, or induced by the investigator. Shunted animal models provide a unique potential for insight into questions concerning the destructive effects of hydrocephalus on the brain and its development, as it is rarely possible to obtain brain tissue from humans with hydrocephalus. Most of the hydrocephalus animal models are neonatal or juvenile animals and the majority of research is thus directed at congenital or pediatric hydrocephalus.