A matrix is an array of numbers in rows and columns. The horizontal lines in matrices are called rows and the vertical lines are called columns. A matrix with m rows and n columns is called an m-by-n matrix (or mxn matrix) and m and n are called its dimensions. The matrix used in computed tomography determines the scan resolution.
Matrices are useful to record data that depend on two categories, and to keep track of the coefficients of systems of linear equations and linear transformations.

See also Image Resolution and Zooming.

The display matrix is the matrix in the displayed image and can be equal to or larger than the reconstruction matrix size due to interpolation procedures. This array of rows and columns of pixels is typically between 512 x 512 and 1024 x 1024.

The reconstruction matrix is the array of rows and columns of pixels in the reconstructed image.

In medical imaging, resolution is the ability to distinguish two adjacent objects and a measurement of image quality. The resolution of tomographic images is a function of slice thickness, field of view (FOV) and matrix size. The resolution in plane is a function of FOV / matrix size.

This term usually refers to the storage of patient data and images. Images are best archived in digital form (e.g., on optical disks, DVDs, PACS systems) and not only on films (hard copies, prints). Data compression via a reduction in matrix size, pixel depth or CT numbers, will result in a loss of spatial and contrast resolution. Digital images should be converted into a universal format such as DICOM. Raw data saving is necessary when additional image reconstructions are required.

See also Picture Archiving and Communication System, and Digital Imaging and Communications in Medicine.