Improved metal suppression using new generation low-field MRI: a biophantom feasibility study.

Area of Science:

• Radiology and Imaging Science
• Biomedical Engineering
• Materials Science in Medicine

Background:

• Metal artifacts are a significant limitation in Magnetic Resonance Imaging (MRI) of patients with orthopedic implants.
• Higher field strength MRI (e.g., 3.0 T) can exacerbate metal artifact issues, potentially obscuring critical anatomical details.

Purpose of the Study:

• To compare the size of metal artifacts and the depiction of anatomical structures between novel 0.55 T and conventional 3.0 T MRI systems.
• To evaluate the effectiveness of different MRI sequences in mitigating metal artifacts at varying field strengths.

Main Methods:

• The study utilized a biophantom model with porcine knee specimens containing stainless steel and titanium screws.
• Imaging was performed at 0.55 T and 3.0 T using Turbo Spin-Echo (TSE), TSE with View Angle Tilting (VAT), and Slice Encoding for Metal Artifact Correction (SEMAC) sequences.
• Artifact size was quantified, and visualization of key anatomical structures (cartilage, bone, ligaments) was assessed and compared.

Main Results:

• Metal artifacts were significantly smaller at 0.55 T compared to 3.0 T.
• The SEMAC sequence at 0.55 T demonstrated the greatest artifact reduction, with relative size decreases of up to 79.4% for stainless steel and 45.3% for titanium.
• Depiction of anatomical structures, including cartilage and ligaments, was superior at 0.55 T.

Conclusions:

• Novel 0.55 T MRI systems offer substantial reduction in metal artifacts, leading to improved anatomical visualization.
• These findings suggest potential patient-relevant advantages for 0.55 T MRI in orthopedic implant imaging.
• Further clinical studies are warranted to confirm the clinical utility and patient benefits of 0.55 T MRI.