Tomographic images
- are made up of little squares called "pixels" (picture elements),
each of which takes a grey-scale value from 1 (black) to 256 (white). Each
pixel represents brain tissue which is about 1 mm. on each of two sides. The
thickness of the slice is often 3 or 5 mm, thus creating a three-dimensional
volume element, or "voxel", which is shaped like a shoe box. Pixel
intensity represents an average from tissue within the voxel.
Image Types: