Imaging of Communicating Hydrocephalus.

Hydrocephalus basically means an increase in the volume of cerebrospinal fluid (CSF) and the ventricles. As simple as it may sound, the definition and classification of hydrocephalus have been a matter of debate over many decades. Many international neurosurgical and radiological workgroups have tried to develop a consensus and over the last 5-10 years have been able to put forth a more well-defined and standardized approach. Though, the debate and controversy surrounding this topic is expected to continue, we have tried to review the most recent and consensually accepted definition and classification. Although conventionally classified as either "obstructive and nonobstructive" or "communicating and noncommunicating," none of the classification schemes were without confusion and errors. A more precise nomenclature is to divide hydrocephalus as either "communicating": with or without obstruction of CSF absorption, or as "noncommunicating": with definite obstruction to CSF absorption. We discuss communicating hydrocephalus in the current article, and the subsequent article deals with noncommunicating hydrocephalus.