Which artifact is mitigated by reducing the slice thickness?

Which artifact is mitigated by reducing the slice thickness?

• A. Range ambiguity
• B. Slice thickness artifact
• C. Mirror image
• D. Propagation speed error

Answer: (A)

Reducing slice thickness mainly improves depth localization in a tomographic image. When you image with a thicker slice, signals from structures at various depths within that slice are merged together, so you can’t tell exactly where along the depth the signal originated. This is called range ambiguity—the uncertainty about the exact depth of features. Thinner slices narrow the depth range from which the signal can arise, so the origin is localized more precisely. That direct reduction of depth uncertainty is why decreasing slice thickness mitigates range ambiguity. Other artifacts aren’t addressed in the same direct way by slicing thinner. For example, a mirror-image artifact comes from reconstruction geometry or aliasing effects, not primarily from slice thickness. Propagation speed error comes from using the wrong wave speed in the medium, which slice thickness doesn’t fix. And while reducing thickness can lessen some partial-volume effects, the artifact most directly mitigated by thinner slices is the range ambiguity.

Reducing slice thickness mainly improves depth localization in a tomographic image. When you image with a thicker slice, signals from structures at various depths within that slice are merged together, so you can’t tell exactly where along the depth the signal originated. This is called range ambiguity—the uncertainty about the exact depth of features.

Thinner slices narrow the depth range from which the signal can arise, so the origin is localized more precisely. That direct reduction of depth uncertainty is why decreasing slice thickness mitigates range ambiguity.

Other artifacts aren’t addressed in the same direct way by slicing thinner. For example, a mirror-image artifact comes from reconstruction geometry or aliasing effects, not primarily from slice thickness. Propagation speed error comes from using the wrong wave speed in the medium, which slice thickness doesn’t fix. And while reducing thickness can lessen some partial-volume effects, the artifact most directly mitigated by thinner slices is the range ambiguity.