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= A Framework for Joint Analysis of Structural and Diffusion MRIs =


{|
|[[Image:pipeline.png|thumb|200px|Joint structural and diﬀusion image analysis pipeline.]]
|}

= Description =
This framework addresses the simultaneous alignment and ﬁltering of DWI images to 
correct eddy current artifacts and the subsequent alignment of those images to structural, T1 MRI to correct for susceptibility artifacts, and this 
paper demonstrates the importance of performing these corrections. It also shows how a T1-based, group speciﬁc atlas can be used to generate 
grey-matter regions of interest that can drive subsequent connectivity analyses. The result is a system that can be combined with a variety of 
tools for MRI analysis for tissue classiﬁcation, morphometry, and cortical parcellation. 


* ''Eddy Current Correction'' 

 We implemented the diffusion weighted image (DWI) registration model from the paper of G.K.Rohde et al.  [[Image:DTIregistration.png|thumb|256px|Coronal slice from a unregisted DTI (left). The same slice after applying the registration model (right).]]
Patient head motion and eddy currents distortion cause artifacts in maps of diffusion parameters computer from DWI. 
This model corrects these two distortions at the same time including brightness correction.


* "Structural Image Preprocessing"
 Preprocess structural images to remove skull, correct bias ﬁeld, normalize 
intensities, and segment tissue classes (to provide a white matter mask).

* "Group Atlas"
 Build a structural atlas from all sub jects’ T1 images. 

Seed regions for tract endpoints are manually delineated in the structural atlas and then mapped 
from the atlas to each individual.  Automatically segment white matter tracts and quantify diﬀusion properties 
using volumetric pathway analysis. 

{|
|[[Image:seeds.png|thumb|256px|The structural atlas built from the ﬁve T1 images with manually outlined 
frontal forceps seeds (left). The seeds mapped to each of the individual cases (right).]]
|[[Image:tracts.png|thumb|256px|Tracts]]
|}

[1] G.K.Rohde, A.S.Barnett, P.J.Basser, S.Marenco, and C.Pierpaoli, et al., "Comprehensive Approach for Correction of Motion and Distortion in Diffusion-Weighted MRI," Magnetic Resonance in Medicine 51:103-114(2004)

= Key Investigators =

* Utah: Ran Tao, Tom Fletcher, Ross Whitaker