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Minimizing artifacts caused by metallic implants at MR imaging: experimental and clinical studies
1Department of Diagnostic Radiology, Yonsei University College of Medicine, Research Institute of Radiological Science, Seoul, Korea.
AJR. American Journal of Roentgenology
|November 3, 1998
Summary
Metallic implants cause MR imaging artifacts. Optimizing implant positioning and using fast spin-echo sequences with specific parameters can significantly reduce these artifacts for better knee imaging.
Area of Science:
- Radiology
- Medical Imaging
- Biomedical Engineering
Background:
- Metallic implants in patients undergoing Magnetic Resonance (MR) imaging can cause significant image artifacts.
- These artifacts can obscure critical anatomical details, potentially impacting diagnosis and treatment planning.
Purpose of the Study:
- To investigate the impact of metallic implant positioning on MR imaging artifacts.
- To identify optimal imaging conditions for minimizing these artifacts.
- To demonstrate the utility of artifact reduction techniques in knee MR imaging.
Main Methods:
- MR imaging of experimental phantoms with titanium alloy and stainless steel screws.
- Comparison of artifact magnitudes across various pulse sequences and imaging parameters.
- Evaluation of clinical MR images of knees with metallic implants (n=19) to assess geometric distortion.
Main Results:
- Titanium alloy screws produced fewer artifacts than stainless steel screws.
- Artifacts were reduced with fast spin-echo (FSE) sequences, parallel screw orientation to the main magnetic field, and smaller voxel sizes.
- FSE imaging showed less obscuration of articular structures compared to spin-echo imaging.
Conclusions:
- Optimizing patient positioning within the MR magnet is crucial for minimizing artifacts.
- Selecting FSE sequences with an anterior-posterior frequency-encoding direction and the smallest feasible voxel size effectively reduces MR artifacts associated with metallic implants.