Identification of cholesterol in fluid from an intracranial cyst by x-ray diffraction.

The use of X-ray diffraction to identify crystals from the fluid obtained from a brain tap is illustrated. The procedure for making this type of analysis is described and a very brief description of X-ray diffraction process given. Photographs of the powder diffraction patterns are included, as well as a table giving the interplanar distances and relative intensities corresponding to the pattern for cholesterol.