PITCH ARTIFACTS IN MULTISECTION SCANNING

As helical pitch increases, the number of detector rows intersecting the image plane per rotation increases and the number of "vanes" in the windmill artifact increases. One of the benefits of z-filter interpolators is that they reduce the severity of windmill artifacts, especially when the image reconstruction width is wider than the detector acquisition width. Artifacts may also be slightly reduced by using noninteger pitch values relative to detector acquisition width, such as pitches of 3.5 or 4.5 on a four-section scanner. This is because z-axis sampling density is optimized for noninteger pitches.