Some Observations on the Circulation of Phenosulfonpthalein in Cerebrospinal Fluid: Normal Flow and the Flow in Hydrocephalus

HE injection of phenosulfonpthalein (PSP) into the lateral ventricles is followed, usually within minutes, by the appearance of the dye in the cerebrospinal fluid (CSF) of the basilar cisterns and subarachnoid space. Failure of the dye to appear, or any substantial delay in its rate of appearance, may be regarded as strong evidence of an obstruction of the ventricular system. On this basis, the dye has been widely used in the clinical diagnosis of hydrocephalus and has served to distinguish the obstructive and communicating types reliably.I, 7 In the current experiment, the circulation of PSP in the ventricles and subarachnoid space of normal and hydrocephalic animals was investigated. A number of observations concerning the normal migration of the dye as well as its altered circulation in obstructive and communicating hydrocephalus have not been previously reported. The significance of these findings is discussed.