Imaging near titanium total hip arthroplasty at 0.55 T compared with 3 T

Area of Science:

• Radiology
• Biomedical Engineering
• Materials Science

Background:

• Patients with orthopedic metallic implants, such as titanium total hip arthroplasty (THA), often require magnetic resonance imaging (MRI) for adjacent tissue evaluation.
• MRI performance, including signal-to-noise ratio (SNR) and artifact levels, is influenced by magnetic field strength.

Purpose of the Study:

• To compare the effectiveness of 0.55 Tesla (T) and 3 T MRI for imaging patients with titanium THA.
• To assess artifact levels and diagnostic confidence at different MRI field strengths for titanium implants.

Main Methods:

• Six patients with titanium THA underwent MRI scans using similar protocols at both 0.55 T and 3 T.
• Scanned sequences included proton density (PD) weighted turbo spin echo (TSE), PD TSE with view-angle tilting (VAT), PD slice encoding for metal artifact correction (SEMAC), and STIR-SEMAC.
• Images were qualitatively and quantitatively compared by two blinded readers.

Main Results:

• Diagnostic confidence was significantly higher at 0.55 T compared to 3 T.
• Perceived metal artifact was substantially reduced at 0.55 T.
• Diagnostic imaging was achievable at 0.55 T without and with multi-spectral imaging (MSI) for PD weighted images.

Conclusions:

• 0.55 T MRI provides substantially reduced metal artifacts and higher diagnostic confidence for titanium THA imaging compared to 3 T MRI.
• Advanced multi-spectral techniques may not be necessary for titanium implants at lower field strengths.