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

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.

Reconstruction is the mathematical process by which the displayed image is produced from the raw data.
Used equipment and data processing methods to reconstruct CT images:
See also Zoom Reconstruction, Reconstruction Matrix and Multiplanar Reconstruction.

Contrast is the relative difference of intensities in two adjacent regions of an image. When referring to computed tomography (CT), contrast is defined as a difference in Hounsfield units between structures. The measurement of contrast resolution in CT imaging involves determining how easy it is to differentiate tissues whose CT density is similar to that of their surroundings. An image lacks contrast when there are no sharp differences between black and white. Brightness refers to the overall lightness or darkness of an image.
The contrast between air, soft tissue, and bones in x-ray and CT images is based on their different absorption of x-rays. Differences in tissue density, thickness and changes of the x-ray spectrum have consequences for image contrast, image noise as well as patient dose.
Optimized tube current, collimation, pitch and image reconstruction improves the contrast. Higher image contrast is produced by increased slice thickness, smaller matrix, and large field of view which results in large voxel size; high mAs to reduce noise; low pass filter.

See also Contrast Enhanced Computed Tomography.

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.