MRI blind zone: A proposed novel index for spinal implants artifacts
Ran Harel1, Gil Kimchi1, Nachshon Knoller1
1Spine Surgery Division, Department of Neurosurgery, Sheba Medical Center Affiliated to Sackler Medical School, Tel-Aviv University, Ramat-Gan, Israel.
Background:
To advocate the formulation of a new index termed MRI Blind Zone, designated to predict the dimensions of the magnetic resonance metallic artifact caused by specific spinal implants. The index may also specify the obscured organs of interest.
Methods:
A retrospective evaluation of post-operative MR images of patients operated for spinal instrumentation with various implants from different materials, in our institution, was performed. The MRI blind zone was described for each product, and the related obscured region of interest was discussed. A proposed 3D model was created as an example for suggested future reporting by the implants' industry.
Results:
Seven implant types are presented. The post-operative MR artifacts were detailed, and the clinical implications were discussed. Material type, processing methods and individual anatomical traits have a dramatic effect on the MRI blind zone and the obscured regions.
Conclusion:
MRI artifact is multifactorial and is influenced in part by the implant's shape, size, material and processing method. Individual products affect post-operative MR artifacts to different extents, and may carry clinical implications when post-operative imaging is required. A standardized index displaying the predicted post-operative artifact is warranted. For the manufacturers to accurately report the data to the surgeons, a parametric standardization should be performed. MRI blind zone index will allow surgeons to compare between different implants efficiently, and improve the informed decision-making process of implant selection.
Insights
A new MRI Blind Zone index is proposed to predict metallic artifact size from spinal implants. This index helps surgeons understand imaging limitations and choose implants more effectively.
Area of Science:
- Medical Imaging
- Biomedical Engineering
- Orthopedic Surgery
Background:
- Metallic implants in spinal surgery can cause significant artifacts on Magnetic Resonance Imaging (MRI).
- These artifacts obscure critical anatomical structures, complicating post-operative assessment.
- Predicting and quantifying these artifacts is essential for patient management.
Purpose of the Study:
- To introduce and advocate for a novel index, the MRI Blind Zone.
- This index aims to predict the dimensions of MRI artifacts caused by spinal implants.
- It also seeks to identify obscured organs of interest due to these artifacts.
Main Methods:
- Retrospective analysis of post-operative MRI scans from patients with various spinal implants.
- Detailed description and measurement of the MRI blind zone for different implant types.
- Development of a proposed 3D model for standardized industry reporting.
Main Results:
- Seven distinct implant types were analyzed, detailing their associated post-operative MRI artifacts.
- The study highlights the clinical implications of these artifacts.
- Implant material, processing, and patient anatomy significantly influence artifact size and obscured regions.
Conclusions:
- MRI artifact is a complex phenomenon influenced by implant characteristics (shape, size, material, processing) and patient anatomy.
- Different implants produce varying degrees of artifact, impacting clinical decisions, especially for post-operative imaging.
- A standardized MRI Blind Zone index is needed for efficient implant comparison and informed surgical decision-making.
