Difference between revisions of "Projects:RegistrationLibrary:RegLib C06"

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[[Image:Button_green_moving.jpg|20px|lleft]]  this indicates the moving image that determines the registration transform.  <br>
 
[[Image:Button_green_moving.jpg|20px|lleft]]  this indicates the moving image that determines the registration transform.  <br>
 
|-
 
|-
|[[Image:Button_red_fixed.jpg|40px|lleft]]  T1 SPGR
+
|[[Image:Button_red_fixed.jpg|40px|lleft]]  axial
 
|
 
|
 
|[[Image:Button_green_moving.jpg|40px|lleft]] T1 SPGR  
 
|[[Image:Button_green_moving.jpg|40px|lleft]] T1 SPGR  
 
|-
 
|-
|0.9375 x 0.9375 x 1.4 mm<br> 256 x 256 x 112<br>RAS
+
|0.44 x 0.44 x 5 mm<br> 784 x 784 x 30<br>RAS
 
|
 
|
|0.9375 x 0.9375 x 1.2 mm<br> 256 x 256 x 130<br>RAS
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|0.68 x 0.68 x 1.5 mm<br> 515 x 515 x 93<br>RAS
 
|}
 
|}
 
===Objective / Background ===
 
===Objective / Background ===
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*contrast enhancement and pathology and treatment changes cause additional differences in image content
 
*contrast enhancement and pathology and treatment changes cause additional differences in image content
 
*the surface coils used cause strong differences in intensity inhomogeneity.  
 
*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
 
*resolution and FOV change between the two scans
  

Revision as of 15:58, 23 February 2010

Home < Projects:RegistrationLibrary:RegLib C06

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Slicer Registration Use Case Exampe #6: Breast MRI Treatment Assessment

this is the fixed reference image. All images are aligned into this space lleft this is the moving image. The transform is calculated by matching this to the reference image LEGEND

lleft this indicates the reference image that is fixed and does not move. All other images are aligned into this space and resolution
lleft this indicates the moving image that determines the registration transform.

lleft axial lleft T1 SPGR
0.44 x 0.44 x 5 mm
784 x 784 x 30
RAS
0.68 x 0.68 x 1.5 mm
515 x 515 x 93
RAS

Objective / Background

We seek to align the post-treatment (PostRx) scan with the pre-treatment scan to compare local effects.

Keywords

MRI, breast cancer, intra-subject, treatment assessment, change detection, non-rigid registration

Input Data

  • Button red fixed white.jpgreference/fixed : T1 SPGR , 0.9375 x 0.9375 x 1.4 mm voxel size, axial, RAS orientation.
  • Button green moving white.jpg moving: T1 SPGR , 0.9375 x 0.9375 x 1.2 mm voxel size, sagittal, RAS orientation.

Registration Results

Download

Link to User Guide: How to Load/Save Registration Parameter Presets


Discussion: Registration Challenges

  • soft tissue deformations during image acquisition cause large differences in appearance
  • 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)