Metal artefact suppression at 3 T MRI: comparison of MAVRIC-SL with conventional fast spin echo sequences in patients with Hip joint arthroplasty

Abstract

Objective: The aim of our study was to evaluate the clinical feasibility and diagnostic value of a new MRI metal artefact reduction pulse sequence called MAVRIC-SL in a 3 T MRI environment.

Subjects and methods: Two MAVRIC-SL sequences obtained in 61 patients with symptomatic total hip replacement were compared with standard FSE-STIR sequences optimized for imaging around metal. Artefact size was measured on the slice of greatest extent. Image quality, fat saturation, image distortion, visibility of anatomical structures, and detectability of joint abnormalities were visually assessed and graded on qualitative scales. Differences between MAVRIC-SL and FSE sequences were tested with the Wilcoxon signed-rank test.

Results: MAVRIC-SL sequences at 3 T showed significantly smaller metal artefacts compared to FSE-STIR sequences (p < 0.0001). The general image quality of MAVRIC-SL sequences was reduced with regard to spatial resolution, noise and contrast (p = 0.001), and fat saturation (p < 0.0001). The reduction of artefact size and image distortion significantly improved visualization of joint anatomy (p < 0.0001) and diagnostic confidence regarding implant-associated abnormalities (p = 0.0075 to <0.0001).

Conclusion: Although the image quality of MAVRIC-SL sequences is limited at 3 T, its clinical application is feasible and provides important additional diagnostic information for the workup of patients with symptomatic hip replacement through substantially reduced metal artefacts.

Key points: • Metal artefacts compromise imaging of total hip replacement with MRI. • Metal artefacts are aggravated with 3 Tesla MRI. • MAVRIC-SL is a technique to suppress metal artefacts. • MAVRIC-SL effectively reduces metal artefacts at 3 Tesla and improves diagnostic quality.