Current and Novel Techniques for Metal Artifact Reduction at CT: Practical Guide for Radiologists

Area of Science:

• Medical Imaging
• Radiology
• Image Processing

Background:

• Metallic implants in computed tomography (CT) cause artifacts like streaks, reducing image quality and diagnostic accuracy.
• These artifacts stem from physical effects such as photon starvation and beam hardening when X-rays interact with metal objects.
• Existing methods aim to improve image quality and recover underlying structural information.

Purpose of the Study:

• To compare and contrast projection-based metal artifact reduction (MAR) algorithms and dual-energy CT (DECT) techniques for mitigating artifacts caused by metallic implants.
• To inform radiologists about the clinical and technical features of each method for optimal patient management.

Main Methods:

• Projection-based MAR algorithms interpolate corrupted projection data to reduce artifacts, primarily addressing photon starvation.
• Dual-energy CT (DECT) utilizes two different X-ray energy spectra to synthesize virtual monochromatic images.
• High kiloelectron volt virtual monochromatic images from DECT are effective in reducing beam hardening artifacts.

Main Results:

• MAR algorithms are applied post-acquisition and primarily target photon starvation artifacts.
• DECT requires pre-acquisition decisions and offers synthesized images that reduce beam hardening.
• Both methods aim to enhance image quality in the presence of metallic implants.

Conclusions:

• Radiologists need to understand the distinct characteristics of MAR algorithms and DECT.
• The choice between MAR and DECT depends on the clinical situation and the specific artifacts encountered.
• Familiarity with these techniques allows for optimal selection to improve CT diagnostic value in patients with metallic implants.