Imaging of Cerebrospinal Fluid Shunts and Their Complications

Hydrocephalus, characterized by excessive intracranial accumulation of cerebrospinal fluid (CSF) in the ventricular system as a result of excessive production, decreased absorption, or impaired circulation of CSF, is a common condition affecting 1%-2% of the U.S. population. More than 40 000 CSF shunts are placed every year in the United States, the majority of which are for treatment of hydrocephalus. Temporary options for CSF diversion include serial lumbar or ventricular punctures, ventriculosubgaleal shunt, external ventricular drain, and ventricular access device. Permanent CSF diversion options include endoscopic third ventriculostomy, endoscopic choroid plexus cauterization, and lumbar and ventricular shunts. Shunt components include a proximal catheter, reservoir, valve, and distal catheter. Shunt failure or dysfunction is a common problem with failure rates of approximately 14% within the 1st month, 40% at 1 year, and 50% by the 2nd year after placement. Shunt malfunction is initially suspected based on the history and physical examination findings of raised intracranial pressure, with imaging often allowing confirmation of the diagnosis and revealing the underlying cause. Shunt complications can be categorized into early and late complications. Early complications include tip misplacement and improper connection of the shunt components, while late complications include fracture, shunt erosion, and overdrainage. It is important to note that shunt obstruction, infection, or tip migration can occur at any time. Thus, radiologists should be familiar with the imaging manifestations of shunt malfunction and complications. ^©RSNA, 2026 Supplemental material is available for this article.