The resolution element has the size of the smallest spatially resolved region in an image. It may be anisotropic, e.g. with an asymmetric acquisition matrix or slice thickness, and may be larger than the pixel or voxel.

A plane, slice or section of the body cutting from front to back through the sagittal suture of the skull, and continued down through the body in the same direction, dividing it into two parts.

A collection of slices with the same orientation. Multi-stack acquisitions are possible when the stack parameter is greater than one, for example in lumbar spine CT exams with individual angulation (oblique) for every disc.

A voxel is a volume element (volumetric pixel) representing a value in the three dimensional space (expressed in units of mm³), corresponding to a pixel for a given slice thickness. Voxels are frequently used in the visualization and analysis of medical data. The CT pixel intensity is proportional to the signal intensity of the appropriate voxel. Voxels are associated with CT numbers.