CT stair-step artifact

CT stair-step

artifact • Stair step artifact (CT) - Ganzer Fall bei Radiopaedia

Cuete, D. Stair step artifact (CT). Case study, Radiopaedia.org. (accessed on 01 Nov 2022) https://doi.org/10.53347/rID-27480 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

The CT stair-step artifact is found in straight structures which are oriented obliquely with respect to movement of the table and appear around the edges of sagittal and coronal reformatted images when wide collimations and non-overlapping reconstruction intervals are used.

It is also seen in coronary CT angiography when step-wise reconstructions are from different cardiac phases. This is associated with heart rate variability and irregular heart rates.

Solution

This can be minimized by, using smaller collimation and overlapping reconstruction in helical imaging.

In coronary CT angiography, 256 and 320-detector CT scanners typically avoid this artifact. Some authors recommend beta-blockers to reduce stair-step artifact, others report limited results in achieving target heart rates with their use.