Normal-Pressure Hydrocephalus-Reply

Abstract

In Reply.— Since it is difficult, on clinical grounds alone, to determine who will benefit from a cerebrospinal fluid shunt procedure, much attention has been given to the various forms of laboratory investigation. These include, in addition to the scinticisternogram, the estimation of blood radionuclide concentrations, monitoring of intracranial pressure, and lumbar saline infusion tests, among others. Unfortunately, there is no general agreement about which tests, either singly or together, can best predict a shunt outcome. 1 Radioisotope cisternography evaluates the possibility of impaired cerebrospinal fluid absorption via an observation of cerebrospinal fluid movement and stasis. In a normal patient, one observes a brisk reabsorption of the tracer by the venous circulation. Unfortunately, the correlation of an abnormal pattern with surgical outcome remains poor. 2 Thus, despite all available technology, the most important prognostic factors remain clinical, followed by information gleaned from the computed tomographic scan. Tests that show some