Metal artifact reduction in cone beam computed tomography using forward projected reconstruction information

Area of Science:

• Medical Imaging
• Radiology
• Computer-Aided Diagnosis

Background:

• Metal artifacts in X-ray cone beam computed tomography (CBCT) degrade image quality, impacting clinical diagnostics and treatment planning.
• High-density objects, particularly metal implants, cause significant artifacts due to their high X-ray attenuation.
• Existing methods struggle to effectively mitigate these artifacts, necessitating novel approaches.

Purpose of the Study:

• To develop and present a novel method for reducing metal artifacts in CBCT imaging.
• To virtually replace metal objects with anatomically similar tissue to minimize image distortions.
• To improve the diagnostic and therapeutic utility of CBCT data in the presence of metallic materials.

Main Methods:

• Segmentation of metal objects in both 2D projection data and the reconstructed 3D volume.
• Virtual replacement of metal's attenuation coefficients with those of surrounding tissue (e.g., water).
• Projection of corrected tissue data onto 2D pixels and subsequent artifact-reduced reconstruction, followed by re-insertion of segmented metal objects.

Main Results:

• Successful reduction of metal artifacts in CBCT images using the proposed virtual replacement technique.
• Demonstration of artifact mitigation in clinical data acquired with mobile C-arm CBCT systems.
• Validation of the method's ability to handle misalignment issues inherent in low-weight C-arm systems.

Conclusions:

• The presented method effectively reduces metal artifacts in CBCT, enhancing image clarity.
• This technique offers a promising solution for improving diagnostic accuracy in patients with metallic implants.
• The approach is particularly relevant for mobile C-arm CBCT applications where image distortions are common.