AN ENCEPHALOGRAPHIC RATIO FOR ESTIMATING THE SIZE OF THE CEREBRAL VENTRICLES

Abstract

In a previous communication¹ an encephalographic ratio was proposed for estimating the size of the cerebral ventricles and the degree of atrophy of the brain. The ratio was obtained by dividing the transverse diameter of the anterior horns by the maximum internal diameter of the skull. Measurements were made on encephalographic films exposed in the anteroposterior projection at 30 inches (76 cm.) with the patient horizontal and the occiput down. Considerations of magnification by projection were dealt with and the results in 212 cases reported. In a "normal" group the great majority of the values for the ratio fell between 0.20 and 0.25, and a statistical correlation was obtained between the diameter of the anterior horns and the internal diameter of the skull indicating that the ratio was not influenced by age or by the size of the skull. Values of the ratio between 0.25 and 0.30 were thought