Projects:RegistrationLibrary:RegLib C14
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Contents
Slicer Registration Use Case Exampe #14: Intra-subject Brain PET-MRI with MRI orientation adjustment
Objective / Background
Image fusion.
Keywords
PET-MRI, brain, intra-subject, image fusion
Input Data
- reference/fixed : baseline MRI: 0.97 x 0.97 x 3.27 mm , PET: 4.7 x 4.7 x 3.3 mm
- moving: PET: 4.1 x 4.1 x 5 mm
Registration Results
Download
- download full tutorial set (Data+intermediate results+presets+tutorial, zip file 17 MB)
- download example data set (Data only, zip file 16 MB)
- download step-by-step tutorial (PowerPoint 1.2 MB)
Link to User Guide: How to Load/Save Registration Parameter Presets
Discussion: Registration Challenges
- the original DICOM files of the MRI have image orientation data stripped. Hence the volume does not load in correct orientation and needs to be adjusted
- the two series have different voxel sizes
- image content and resolution in PET is low
Discussion: Key Strategies
- we use the Volumes module to adjust the MRI voxel size based on the info in the DICOM header
- we use the Transforms module to reorient the MRI along the proper axes
- the aspect ratio we correct via the "Volumes" module. The correct slice thickness we obtain from the DICOM header via the browser displayed when selecting "Add Volume"
- the "Transforms" module is used to correct orientation. We enter manual rotations of 90 and 180 degrees around the LR (left-right) and IS (inferior-superior) axes, respectively
- the corrected MRI volume is resampled in the Data module via "harden transforms"
- Register Images is used to automatically align the PET with the MRI. We choose mutual information ("MI") as the criterion and a 5% sampling rate. We request an affine transform to correct for small distortion differences between the PET and the MRI