Metal artifact reduction by dual-layer computed tomography using virtual monoenergetic images

Area of Science:

• Radiology
• Medical Imaging
• Computed Tomography

Background:

• Metal artifacts pose a significant challenge in computed tomography (CT) imaging, particularly in patients with orthopedic implants.
• Dual-layer computed tomography (DLCT) offers advanced image reconstruction capabilities, including virtual monoenergetic imaging (VMI).

Purpose of the Study:

• To evaluate the effectiveness of VMI in reducing metal artifacts.
• To assess the diagnostic performance and value of VMI in DLCT for patients with orthopedic implants.

Main Methods:

• 35 patients with orthopedic implants undergoing DLCT were included.
• Virtual monoenergetic images were reconstructed at various energy levels (64-200 keV and optimized).
• Images were analyzed by blinded observers for subjective (image quality, artifact extent) and objective (artifact width, density) criteria.

Main Results:

• Diagnostic image quality significantly improved (Likert score from 4.3 to 2.3) with higher photon energies.
• Metal artifact extent and severity were significantly reduced.
• Optimized VMI (average 149.2 keV) and 140 keV VMI demonstrated substantial artifact reduction compared to standard reconstructions.

Conclusions:

• VMI in DLCT effectively reduces metal artifacts, enhancing diagnostic image quality in patients with orthopedic implants.
• 140 keV VMI provides optimal artifact reduction, with potential for further improvement using individually optimized keV in select cases.