What is a pixel, a voxel, a matrix?
A CT image is composed of a square image matrix that ranges in size from 256 X 256 to 1024 X 1024 picture elements or pixels. Since a CT section has a finite thickness, each pixel actually represents a small volume element, or voxel. The size of this voxel depends on the matrix size, the selected field of view (FOV), and the section thickness.