J Korean Soc Radiol.  2022 Nov;83(6):1286-1297. 10.3348/jksr.2021.0130.

Comparison of Metal Artifact Reduction Algorithms in Patients with Hip Prostheses: Virtual Monoenergetic Images vs. Orthopedic Metal Artifact Reduction

• Yoo HJ
• Hong SH
• Choi JY
• Chae HD

• KMID: 2536817
• DOI: http://doi.org/10.3348/jksr.2021.0130

Abstract

Purpose
To assess the usefulness of various metal artifact reduction (MAR) methods in patients with hip prostheses.
Materials and Methods
This retrospective study included 47 consecutive patients who underwent hip arthroplasty and dual-energy CT. Conventional polyenergetic image (CI), orthopedic-MAR (O-MAR), and virtual monoenergetic image (VMI, 50–200 keV) were tested for MAR. Quantitative analysis was performed in seven regions around the prostheses. Qualitative assessments included evaluation of the degree of artifacts and the presence of secondary artifacts.
Results
The lowest amount of image noise was observed in the O-MAR, followed by the VMI. O-MAR also showed the lowest artifact index, followed by high-keV VMI in the range of 120–200 keV (soft tissue) or 200 keV (bone). O-MAR had the highest contrast-to-noise ratio (CNR) in regions with severe hypodense artifacts, while VMI had the highest CNR in other regions, including the periprosthetic bone. On assessment of the CI of pelvic soft tissues, VMI showed a higher structural similarity than O-MAR. Upon qualitative analysis, metal artifacts were significantly reduced in O-MAR, followed by that in VMI, while secondary artifacts were the most frequently found in the O-MAR (p < 0.001).
Conclusion
O-MAR is the best technique for severe MAR, but it can generate secondary artifacts. VMI at high keV can be advantageous for evaluating periprosthetic bone.

Keyword

Artifacts; Prosthetic Implants; Metals; Multidetector Computed Tomography; Dual Energy Scanned Projection Radiography