Low-field magnetic resonance imaging offers potential for measuring tibial component migration

Abstract

BackgroundRoentgen stereophotogrammetric analysis (RSA) is used to measure early prosthetic migration and to predict future implant failure. RSA has several disadvantages, such as the need for perioperatively inserted tantalum markers. Therefore, this study evaluates low-field MRI as an alternative to RSA. The use of traditional MRI with prostheses induces disturbing metal artifacts which are reduced by low-field MRI. The purpose of this study is to assess the feasibility to use low-field (0.25 Tesla) MRI for measuring the precision of zero motion. This was assessed by calculating the virtual prosthetic motion of a zero-motion prosthetic reconstruction in multiple scanning sessions. Furthermore, the effects of different registration methods on these virtual motions were tested.ResultsThe precision of zero motion for low-field MRI was between 0.584 mm and 1.974 mm for translation and 0.884° and 3.774° for rotation. The manual registration method seemed most accurate, with μ ≤ 0.13 mm (σ ≤ 0.931 mm) for translation and μ ≤ 0.15° (σ ≤ 1.63°) for rotation.ConclusionLow-field MRI is not yet as precise as today’s golden standard (marker based RSA) as reported in the literature. However, low-field MRI is feasible of measuring the relative position of bone and implant with comparable precision as obtained with marker-free RSA techniques. Of the three registration methods tested, manual registration was most accurate. Before starting clinical validation further research is necessary and should focus on improving scan sequences and registration algorithms.

New-Generation Low-Field Magnetic Resonance Imaging of Hip Arthroplasty Implants Using Slice Encoding for Metal Artifact Correction

“…Low-field MRI improves visualization of the soft tissues near the metallic hardware, owing to the physics principle that susceptibility artifacts are proportional to the field strength. Although this concept has been shown for smaller metallic implants, 9–11 the current gap of knowledge on larger metallic components, such as hip arthroplasty, stems from poor access to whole-body low-field systems, unavailability of advanced metal artifact reduction techniques on such systems, and often poor image quality of the traditional low-field scanners. Initial studies suggest that new-generation low-field MRI systems offer advantages for MRI-guided catheterizations with metal-containing devices and MRI in high-susceptibility regions 12,13 .…”

Modern Low-Field MRI of the Musculoskeletal System

“…Owing to lower susceptibility artifacts, MRI of metallic orthopedic hardware benefits substantially from the lower field strength. [40][41][42] In contrast to the previous generation low-field MRI scanners, modern low-field MRI systems now enable the application of newer metal artifact reduction sequences such as slice encoding for metal artifact correction (SEMAC). [43][44][45][46][47] In a recent in vitro study comparing 0.55 and 1.5 T MRI of hip arthroplasty implants, lower SEMAC-encoding steps at 0.55 T were shown to achieve higher degrees of artifact reduction than 1.5 T MRI.…”

“…Owing to lower susceptibility artifacts, MRI of metallic orthopedic hardware benefits substantially from the lower field strength 40–42 . In contrast to the previous generation low-field MRI scanners, modern low-field MRI systems now enable the application of newer metal artifact reduction sequences such as slice encoding for metal artifact correction (SEMAC) 43–47 …”

Approaches for Image Reconstruction in Low-Field Magnetic Resonance Imaging

“…diagnosing lesions of the rotator cuff, low eld cardiac MRI [36], probing rock pore space using low eld nuclear magnetic resonance technologies [37], musculoskeletal conditions [38], tibial component migration [39], low-eld dental MRI [40], glioma surgery [41] and glenoid labrum (Shoulder pathology) [42].…”