Material-Dependent Implant Artifact Reduction Using SEMAC-VAT and MAVRIC: A Prospective MRI Phantom Study
Lukas Filli1, Lukas Jud, Roger Luechinger
1From the *Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich; †Institute for Biomedical Engineering, University and ETH Zurich, Zurich; ‡Department of Radiology, Kantonsspital Muensterlingen, Muensterlingen; §University of Zurich, Zurich; and ∥Department of Radiology, Hospital and University of Bern, Inselspital, Bern, Switzerland.
Slice Encoding for Metal Artifact Correction (SEMAC) with View Angle Tilting (VAT) and Multiaquisition Variable Resonance Image Combination (MAVRIC) effectively reduce artifacts from metallic implants. The best method depends on the specific metal and desired artifact reduction level.
Area of Science:
- Radiology
- Medical Imaging
- Biomaterials Science
Background:
- Metal artifacts significantly degrade Magnetic Resonance Imaging (MRI) quality, particularly around orthopedic implants.
- Accurate visualization of tissues adjacent to metallic implants is crucial for diagnosis and treatment planning.
Purpose of the Study:
- To compare the efficacy of SEMAC-VAT and MAVRIC in reducing MRI artifacts caused by various metallic prosthetic materials.
- To evaluate artifact reduction across different contrast weightings (T1w, T2w, PDw) and artifact suppression levels.
Main Methods:
- Four types of metallic rods (stainless steel, titanium, cobalt-chromium-molybdenum, oxidized zirconium) were scanned at 3 T.
- Conventional fast spin-echo, SEMAC-VAT, and MAVRIC sequences were applied with varying artifact suppression.
- Artifacts were quantitatively assessed by two independent readers, and simulations were performed.
Main Results:
- Stainless steel generated the most severe artifacts, followed by CoCr, Ti, and oxZi.
- Weak SEMAC-VAT was advantageous for Ti and oxZi, while SS and CoCr required stronger SEMAC-VAT or MAVRIC.
- MAVRIC offered superior artifact reduction but with longer scan times compared to SEMAC-VAT.
Conclusions:
- For titanium and oxidized zirconium implants, weak SEMAC-VAT is recommended due to speed and artifact reduction.
- Significant artifact reduction for stainless steel and cobalt-chromium-molybdenum implants necessitates medium/strong SEMAC-VAT or MAVRIC.
