Combined MRI features to assess periprosthetic hip joint infection with STIR SEMAC and MAVRIC at 1.5 T

Skeletal Radiol. 2026 Jan 29. doi: 10.1007/s00256-026-05132-3. Online ahead of print.

Abstract

Objective: This study was aimed at identifying MRI findings related to total hip arthroplasty (THAs) infection using coronal STIR with metal artifact reduction sequences (MARS) at 1.5 T.

Materials and methods: This retrospective multicenter study included all patients with THAs who underwent 1.5 T MRI with MARS from December 2015 to April 2020. Two groups are as follows: an infected group and a non-infected group (including asymptomatic THAs and symptomatic non-infected THAs). MARS were either multi-acquisition with variable-resonance image combination (MAVRIC) or slice encoding for metal artifact correction (SEMAC). Imaging features were evaluated to assess their association with THA infection (including both symptomatic and asymptomatic patients). Sensitivity, specificity, and accuracy of these imaging findings were assessed, and inter-reader agreement (kappa, K) was determined.

Results: Sixteen patients with THAs had periprosthetic infection, compared with 46 THAs in the non-infected group. Bone edema extending to adjacent soft tissues, defined as a combination of femoral bone marrow edema, hyperintense cortical signal, periostitis, and overall soft tissue edema, had the greatest diagnostic performance for infection: 15/16(94%) infected THAs and 0/46(0%) non-infected THAs (accuracy = 0.98, sensitivity = 0.94, specificity = 1, p < 0.001 Chi-Square test). This combination, predominant in the infected group (p < 0.001 for all), also demonstrated separately high accuracy (acc = 0.94-1), sensitivity (se = 0.94-1), and specificity (0.94-1). Fistula and fluid collection were highly specific (spe = 1) and accurate (acc = 0.81-0.82), although less sensitive (se = 0.25-0.31, p < 0.001).

Conclusion: The combination of femoral bone marrow edema, hyperintense cortical signal, periostitis, and soft tissue edema is accurate in the diagnosis of periprosthetic hip joint infection using coronal STIR with MARs at 1.5 T.

Keywords: Arthroplasty; Artifact; Hip; Magnetic resonance imaging; Prosthetic joint infection.