Radiodense Ions Within a Third Ventricular Colloid Cyst

Abstract
• The mucinous contents of a third ventricular colloid (neuroepithelial) cyst is invisible with standard radiographic techniques, but is radiodense with computerized tomography. Atomic emission spectrometry detected primarily sodium, calcium, and magnesium with the mucin. The absorption coefficient of colloid cysts (42 to 76 Hounsfield units) is attributed to the distribution of calcium throughout the mucin.