Radiographic subtraction in positive contrast ventriculography

Biplane seriographic technique applied to positive contrast ventriculography with water soluble contrast medium allows a better and fuller utilization in the examination. In the case of dilution of the contrast medium in hydrocephalus and in the case of a poor visualization of deformed aqueduct and fourth ventricle, the subtraction technique can be of decisive help in the analysis of the ventriculograms.