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Rigid-body motion correction in hybrid PET/MRI using spherical navigator echoes
P M Johnson1,2, R Taylor3,4,5, T Whelan1
1Robarts Research Institute, Western University, London, ON, Canada.
Physics in Medicine and Biology
|March 19, 2019
Summary
This study introduces spherical navigator echoes (SNAVs) for motion correction in positron emission tomography and magnetic resonance imaging (PET/MRI). SNAVs effectively reduce motion artifacts in PET/MRI scans, improving image quality and quantitative accuracy.
Area of Science:
- Medical Imaging
- Biophysics
Background:
- Integrated PET/MRI offers complementary diagnostic information.
- Motion artifacts significantly degrade PET and MRI data quality due to long acquisition times.
- Simultaneous PET/MRI acquisition necessitates robust motion correction techniques.
Purpose of the Study:
- To develop and evaluate a novel MRI navigator technique for motion correction in simultaneous PET/MRI.
- To assess the impact of incorporating spherical navigator echoes (SNAVs) into a fast imaging sequence on image quality.
- To demonstrate the efficacy of SNAV-based motion correction in reducing artifacts in both PET and MRI data.
Main Methods:
- Development of spherical navigator echoes (SNAVs) for 6-DOF rigid body motion measurement.
- Integration of SNAVs into a turbo FLASH (tfl) sequence to create the tfl-SNAV pulse sequence.
- In vivo brain imaging in a healthy volunteer and phantom studies with simulated motion under simultaneous PET/MRI acquisition.
Main Results:
- The tfl-SNAV sequence showed no detrimental impact on image quality compared to the standard tfl sequence.
- SNAV motion correction successfully reduced motion artifacts in both PET and MR images acquired with an anthropomorphic brain phantom.
- Corrected PET/MRI images exhibited improved image quality and quantitative similarity to reference scans after motion correction.
Conclusions:
- Spherical navigator echoes (SNAVs) provide accurate and rapid measurement of rigid body motion for PET/MRI.
- SNAV-based motion correction is effective in mitigating motion artifacts in simultaneous PET/MRI.
- This technique enhances the diagnostic utility of PET/MRI by improving image quality and quantitative accuracy.
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