CT stair step artifact

Case contributed by Dr David Cuete

Presentation

CTA requested for evaluation of AAA

Patient Data

Age: 40
Gender: Male

CTA Aorta (5mm slice thickness and reconstruction interval of 5 mm)

Modality: CT

In this stack we see the stair-step artifact ont the coronal, sagittal and Volume rendering reformats, . This is due to the anisotropy of the voxel  generated from 5mm thick slices and an interval of 5mm. Appreciate the insufficient image quality for purposes of diagnostic interpretation.

CTA Aorta (5mm slice thickness and reconstruction interval of 2.5 mm)

Modality: CT

In this stack we can see a reduction of the stair-step artifact, although the slice thickness is 5mm, now the reconstruction interval of 5mm was decreased to 2.5 mm which creates more data in the z-axis to improve the reconstruction. The images are still blurring.

CTA Aorta (1,5mm slice thickness and reconstruction interval of 0,75mm)

Modality: CT

In this stack we can see how the artifact disappears completely reformats in the coronal, sagittal 3D. This is because now the volume from which was generated  with thin sections are generated and  overlapping reconstruction, generating an isotropic voxel. Notice how this is a high quality study.

Case Discussion

This case shows how you can improve the quality of a study knowing the principles that govern the generation of artifacts

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Case Information

rID: 27480
Case created: 4th Feb 2014
Last edited: 26th Jul 2016
System: Vascular
Inclusion in quiz mode: Excluded

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