Managing hardware-related metal artifacts in MRI: current and evolving techniques.

Area of Science:

• Radiology
• Medical Imaging
• Biomedical Engineering

Background:

• Metal implants in Magnetic Resonance Imaging (MRI) cause artifacts due to magnetic susceptibility differences.
• These artifacts include signal loss, geometric distortion, and loss of fat suppression, compromising diagnostic accuracy.
• Increasing prevalence of joint replacements necessitates improved imaging for post-operative assessment.

Purpose of the Study:

• To review recent advancements in clinically applicable metal artifact reduction techniques in MRI.
• To discuss improvements in MR hardware and their impact on artifact reduction.
• To provide a comprehensive understanding of metal artifact reduction principles, techniques, and limitations.

Main Methods:

• Hardware improvements: high-density RF coils, parallel imaging, gradient warping correction, susceptibility-matched implants, low-field MRI.
• Sequence-based methods: view-angle tilting (VAT) and slice-encoding for metal artifact correction (SEMAC).
• Reconstruction and post-processing: iterative algorithms, deep learning approaches, and artifact correction techniques.

Main Results:

• Hardware advancements enhance signal, accelerate acquisition, and minimize distortion.
• Specific sequences (VAT, SEMAC) and advanced algorithms effectively reduce metal artifacts.
• Susceptibility-matched implants and low-field MRI decrease magnetic susceptibility differences.

Conclusions:

• Recent developments offer significant improvements in reducing metal artifacts in musculoskeletal MRI.
• A thorough understanding of these techniques and their limitations is crucial for effective clinical application.
• These advancements aid in better radiological assessment for managing post-operative complications.