Hybrid PET/MR imaging: an algorithm to reduce metal artifacts from dental implants in Dixon-based attenuation map
Irene A Burger1, Moritz C Wurnig2, Anton S Becker2
1Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland; and irene.burger@usz.ch.
Summary
This study introduces an algorithm to reduce metal artifacts in PET/MR imaging. The method improves attenuation correction accuracy in areas with dental implants, enhancing image quality for oncologic patients.
Area of Science:
- Medical Imaging
- Radiology
- Biomedical Engineering
Background:
- Hybrid PET/MR imaging offers advanced diagnostic capabilities.
- Metal artifacts from dental implants significantly degrade MR imaging quality, complicating attenuation correction.
- Existing methods struggle to accurately correct for these artifacts.
Purpose of the Study:
- To implement and evaluate an algorithm for modifying Dixon-based MR imaging datasets.
- To reduce metal artifacts in hybrid PET/MR imaging using a multiacquisition variable resonance image combination (MAVRIC) sequence.
- To improve MR imaging-based attenuation correction in critical areas affected by metal.
Main Methods:
- An algorithm was developed to correct Dixon-based attenuation maps using MAVRIC sequences.
- Data were acquired from 8 oncologic patients with dental implants using a trimodality PET/CT and MR imaging setup.
- The algorithm corrected Dixon signal voids in areas compromised by dental implants.
Main Results:
- The algorithm demonstrated robustness across all tested patients.
- A significant 70.5% reduction in mean artifact size was observed (from 697 ± 589 mm² to 202 ± 119 mm²).
- The corrected μ maps showed substantially reduced artifacts compared to uncorrected maps (P = 0.016).
Conclusions:
- The proposed algorithm effectively improves MR imaging-based attenuation correction.
- This method is particularly beneficial in critical areas where standard attenuation correction is hindered by metal artifacts.
- Utilizing MAVRIC sequences enhances the accuracy of attenuation correction in the presence of metallic implants.
