Metal Artefact Reduction Sequences (MARS) in Magnetic Resonance Imaging (MRI) After Total Hip Arthroplasty (THA). A Non-Invasive Approach for Preoperative Differentiation Between Periprosthetic Joint Infection (PJI) and Aseptic Complications?

Abstract Background:In the past, radiographic imaging was of minor relevance in the diagnosis of periprosthetic joint infections (PJI). Since metal artefact reduction sequences (MARS) are available, magnetic resonance imaging (MRI) has become a promising diagnostic tool for the evaluation of hip arthroplasty implants. The purpose of the present study was to evaluate the efficacy of MARS MRI in comparison to established diagnostic tools to distinguish between aseptic failure and PJI.Methods:Between July 2018 to September 2019, MARS-MRI was conducted using the optimized parameters at 1.5 T in a coronal and axial STIR (short-tau-inversion recovery), a non-fat-saturated T2 in coronal view and a non-fat-saturated T1 in transverse view in 45 patients with painful hip after THA.Results:Synovial layering and muscle edema were significant features of periprosthetic joint infection, with sensitivities of 100% and specifities of 63.0 - 75.0%. The combined specifity and sensitivity levels of synovial layering and muscular edema was 88.0% and 90.0%. Granulomatous synovitis was a significant feature for aseptic failure, with 90.0% sensitivity and 57.0% specifity.Conclusion:MARS-MRI is as suitable as standard diagnostic tools to distinguish between aseptic failure and PJI in patients with a total hip arthroplasty (TJA). Further studies with larger patient numbers have to prove whether MARS-MRI could be integral part of PJI diagnostic.