[en] Radionuclide cisternography has proven to be an excellent diagnostic tool in patients suspected of having normal pressure hydrocephalus. It is safe, relatively simple to perform, and can assist the physician in determining which patients would benefit from ventriculovenous shunting or other operative procedures. Six of nine patients with abnormal cisternograms but without ventricular filling improved following a shunting procedure. It was concluded that a shunting procedure is indicated in the absence of ventricular filling. (U.S.)