Difference between revisions of "Projects:RegistrationLibrary:RegLib C06b"
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=== Modules === | === Modules === | ||
− | *'''Slicer 3.6.3 recommended modules: [ | + | *'''Slicer 3.6.3 recommended modules: [https://www.slicer.org/wiki/Modules:BRAINSFit Modules:BRAINSFit]''' |
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##select Presets "Xf1_Affine" or set the parameters as given below: | ##select Presets "Xf1_Affine" or set the parameters as given below: | ||
##fixed image: "PreRx_left", moving image: "PostRx_left" | ##fixed image: "PreRx_left", moving image: "PostRx_left" | ||
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##Click Apply. Execution time ~ 4 seconds | ##Click Apply. Execution time ~ 4 seconds | ||
*'''Phase 2''': BSpline alignment | *'''Phase 2''': BSpline alignment | ||
− | #Go to the [ | + | #Go to the [https://www.slicer.org/wiki/Modules:BRAINSFit '''BRAINSfit'''] module |
##select Presets "Xf2_BSpline1" or set the parameters as given below: | ##select Presets "Xf2_BSpline1" or set the parameters as given below: | ||
##fixed image: "PreRx_left", moving image: "PostRx_left" | ##fixed image: "PreRx_left", moving image: "PostRx_left" |
Latest revision as of 17:51, 10 July 2017
Home < Projects:RegistrationLibrary:RegLib C06bBack to ARRA main page
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Contents
v3.6.3 Registration Library Case #6B: RSNA 2011 DEMO Breast MRI Treatment Assessment
fixed image/target pre Rx MRI |
moving image post Rx MRI |
Modules
- Slicer 3.6.3 recommended modules: Modules:BRAINSFit
Objective / Background
We seek to align the post-treatment (PostRx) scan with the pre-treatment scan to compare local effects (left side only).
Keywords
MRI, breast cancer, intra-subject, treatment assessment, change detection, non-rigid registration
Download
- Data:
- Presets
Input Data
- reference/fixed : 0.44 x 0.44 x 5 mm , 784 x 784 x 30
- moving: 0.68 x 0.68 x 1.5 mm, 515 x 515 x 93
Methods
- Phase 1: affine alignment
- Go to the BRAINSfit module
- select Presets "Xf1_Affine" or set the parameters as given below:
- fixed image: "PreRx_left", moving image: "PostRx_left"
- Initialize with previous transform: select "Off"
- Initialize Transform Mode: check box for use MomentsAlign
- Registration Phases: check boxes for Include Rigid ..." and Include Affine registration phase
- Output: under Slicer Linear Transform, select new and rename to "Xf1_Affine" or similar
- Registration Parameters: this first phase is for initial alignment, we optimize/push for speed
- reduce "Number of Iterations" to 200
- reduce "Number of Samples" to 20,000
- leave rest at defaults
- Click Apply. Execution time ~ 4 seconds
- Phase 2: BSpline alignment
- Go to the BRAINSfit module
- select Presets "Xf2_BSpline1" or set the parameters as given below:
- fixed image: "PreRx_left", moving image: "PostRx_left"
- Initialize with previous transform: select "Xf1_Affine" from phase 1 above
- Initialize Transform Mode: check box for Off
- only check box for Include BSpline registration phase" , all other boxes off.
- Registration Parameters: set "Number of Samples" to 200,000 at least
- Output:
- Slicer BSpline Transform, select new and rename to "Xf2_BSpline" or similar
- Output Image Volume: select new and rename to "PostRx_left_Xf2" or similar
- Output Image Pixel Type: check box for "ushort"
- Registration Parameters:
- set "Number of Samples" to 100,000
- set Number of Grid Subdivisions to 7,7,5
- set Maximum B-Spline Displacement to 10 [mm]
- Click Apply. Execution time ~ 60 seconds
Registration Results
unregistered
affine
BSpline 9x9x4 max 15mm
Deformation field for BSpline 9x9x4 max 10mm
BSpline 7x7x5 max 10mm
After N4 bias correction and histogram equalization:
unregistered
affine
BSpline 7x7x5 max 10mm
Deformation of Post image from unmasked BSpline 7x7x5 max 10mm
BSpline 7x7x5 max 10mm + tumor mask
Deformation of Post image from masked BSpline 7x7x5 max 10mm
EXPERIMENTAL: BRAINSDemonsWarp
Demons: defaults
Demons: cost fn: Demons
Demons: cost fn: FastSymm
Demons: cost fn: LogDemons
Demons: cost fn: SymmetricLogDemons
Demons: cost fn: SymmetricLogDemons_Masked
Discussion: Registration Challenges
- soft tissue deformations during image acquisition cause large differences in appearance
- the large tumor recession represents a significant pre/post difference in image content that will influence unmasked intensity-driven registration, which becomes a problem for the non-rigid portion of registration, particularly at higher DOF, because the registration will try to "recreate" the tumor area from the postRx image in order to match the content.
- contrast enhancement and pathology and treatment changes cause additional differences in image content
- the surface coils used cause strong differences in intensity inhomogeneity.
- we have strongly anisotropic voxel sizes with much less through-plane resolution
- resolution and FOV change between the two scans
Discussion: Key Strategies
- because of the strong changes in shape and position, we break the problem down and register each breast separately.
- we perform a bias-field correction on both images before registration
- we use the Multires version of RegisterImages for an initial affine alignment
- the nonlinear portion is then addressed with a BSpline or DiffeomorphicDemons algorithm
- because accuracy is more important than speed here, we increase the sampling rate (i.e. the number of points sampled for the BSpline registration)