Projects:DBP2:Harvard:Registration Documentation
Contents
Same subject Registration
Slicer 3 contains a number of different ways to register two images. In this document we will examine the results of these modules on three different cases. The convention used will be (moving image) -> (fixed image) = (resulting moved image). The cases are:
- Registering a t2 weighted image to an arbitrary t1, then registering this transformed image back to the original t2. Ideally this will produce a identical image.
- Registering a DTI baseline image to the corresponding realigned t2 weighted image, and vice-versa. This is a realistic test of one of our (the PNL) everyday uses of registration.
- Registering a realigned t2 weighted image to another t2.
Slicer modules
Affine
- 53-t2 -> 31-t1 = aff1
- aff1 -> 53-t2 = aff2
The image shows these side by side. The are nearly the same except for the loss of fine detail.
- DTI-baseline -> 53-t2 = aff3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Image shows the 53-t2 target image and the registered image side by side. DTI distortion remains but aligned well to ventricles in center.
- 53-t2 -> DTI-baseline = aff4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] The registered image does not stretch to the full extent of the DTI at the midline, though the match is quite close more laterally.
Linear
- 53-t2 -> 31-t1 = lin1
- lin1 -> 53-t2 = lin2
The image shows lin2 and 53-t2 side by side. The image shows there appears to be some change beyond loss of detail, possibly a L-R shift in the front.
- DTI-baseline -> 53-t2 = lin3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Middle is clearly matched, coronal slices look okay, sagittal shows DTI distortions remain.
- 53-t2 -> DTI-baseline = lin4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Brainstem and cerebellum matched well, normal DTI distortions still present.
Rigid
- 53-t2 -> 31-t1 = rig1
- rig1 -> 53-t2 = rig2
Significant blurring, but every feature is in it's proper place.
- DTI-baseline -> 53-t2 = rig3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Brainstem aligned, normal DTI distortions present.
- 53-t2 -> DTI-baseline =rig4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Similar.
Deformable B-spline
- 53-t2 -> 31-t1 = Bspline1
- Bspline1 -> 53-t2 = Bspline2
Superior frontal enlargement, odd upward shifting in rear of brain, distortions everywhere.
- DTI-baseline -> 53-t2 = Bspline3
Fits the cortex on the baseline to the skull on the t2. Retry with a skull stripped t2.
- 53-t2 -> DTI-baseline = Bspline4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
- DTI-baseline-masked -> 53-t2-masked = Bspline3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Bad registration, numerous deformations, midline shift in frontal lobe, right side deformations, cerebellum doesn't fit any more.
Diffeomorphic Demons
- 53-t2 -> 31-t1 = Demons1
- Demons1 -> 52-t2 = Demons2
Multiple deformations. Much larger ventricles. Small errors everywhere, expansions, contractions, shifts. Roughly in the same place overall.
- DTI-baseline -> 53-t2 = Demons3
- 53-t2 ->
Register Images Module
Initial
- 53-t2 -> 31-t1 = init1
- init1 -> 53-t2 = init2
Huge shift in count values, rigid translation down ~4 pixels, left ~1 pixel.
- DTI-baseline -> t2 = init3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
- t2 -> DTI-baseline = init4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
Rigid
- 53-t2 -> 31-t1 = rigid1
- rigid1 -> 53-t2 = rigid2
Shift in grey values. Few other problems.
- DTI-baseline -> t2 = rigid3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
- t2 -> DTI-baseline = rigid4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
Affine
- 53-t2 -> 31-t1 = affine1
- affine1 -> 53-t2 = affine2
Again, shift in grey values, mostly okay otherwise. Slight posterior shift.
- DTI-baseline -> t2 = affine3
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
- t2 -> DTI-baseline = affine4
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]
B-Spline
- 53-t2 -> 31-t1 = Bspline1
- Bspline1 -> 53-t2 = Bspline2
Again grey values shift. Minor distortion in frontal lobe and cerebellum.
- DTI-baseline -> t2
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]] Slow process. Inferior frontal, temporal, stretched downwards. Cerebellum is terrible. Very top of the brain is stretched. Pretty bad overall.
- t2 -> DTI-baseline
[[FILE:FILENAME|600px|thumb|left|TYPE case X: explanation]]