Truncated-view artifacts: clinical importance on CT.

A truncated-view artifact in CT is produced whenever any part of the patient or imaged object is present in some but not all of the views obtained for a slice. The potential to create images with this artifact exists for any CT scanner in which the fan beam (or its equivalent) does not cover the entire gantry aperture. This includes most CT systems currently on the market. Although the artifact may not create a severe visual disturbance in the image, it can alter the CT numbers in a manner that will compromise the accuracy of quantitative analyses. This report describes the nature of the truncated-view artifact and presents simulated examples for both mathematical phantoms and clinical scans. The artifact can be eliminated by assuring that the entire patient and all foreign objects are included in the field of view, or it can be minimized by placing objects that cannot be entirely within the field of view as close to the edge of the gantry aperture as possible.