title: Advanced fiber tracking in early acquired brain injury causing cerebral palsy.
abstract: OBJECTIVE
  Diffusion-weighted MR imaging and fiber tractography can be used to investigate alterations in white matter tracts in patients with early acquired brain lesions and cerebral palsy. Most existing studies have used diffusion tensor tractography, which is limited in areas of complex fiber structures or pathologic processes. We explored a combined normalization and probabilistic fiber-tracking method for more realistic fiber tractography in this patient group.
  
  
  METHODS
  This cross-sectional study included 17 children with unilateral cerebral palsy and 24 typically developing controls. DWI data were collected at 1.5T (45 directions, b=1000 s/mm(2)). Regions of interest were defined on a study-specific fractional anisotropy template and mapped onto subjects for fiber tracking. Probabilistic fiber tracking of the corticospinal tract and thalamic projections to the somatosensory cortex was performed by using constrained spherical deconvolution. Tracts were qualitatively assessed, and DTI parameters were extracted close to and distant from lesions and compared between groups.
  
  
  RESULTS
  The corticospinal tract and thalamic projections to the somatosensory cortex were realistically reconstructed in both groups. Structural changes to tracts were seen in the cerebral palsy group and included splits, dislocations, compaction of the tracts, or failure to delineate the tract and were associated with underlying pathology seen on conventional MR imaging. Comparisons of DTI parameters indicated primary and secondary neurodegeneration along the corticospinal tract. Corticospinal tract and thalamic projections to the somatosensory cortex showed dissimilarities in both structural changes and DTI parameters.
  
  
  CONCLUSIONS
  Our proposed method offers a sensitive means to explore alterations in WM tracts to further understand pathophysiologic changes following early acquired brain injury.
authors.affiliation: From the Department of Neuroradiology (F.L., O.F.), Karolinska University Hospital, Stockholm, Sweden Departments of Clinical Neurosciences (F.L., O.F.) finn.lennartsson@karolinska.se.
authors.forename: F
authors.initials: F
authors.lastname: Lennartsson
authors.affiliation: Women's and Children's Health (L.H., A.-C.E., H.F., B.V.), Karolinska Institute, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Holmström
authors.affiliation: Women's and Children's Health (L.H., A.-C.E., H.F., B.V.), Karolinska Institute, Stockholm, Sweden.
authors.forename: A-C
authors.initials: AC
authors.lastname: Eliasson
authors.affiliation: From the Department of Neuroradiology (F.L., O.F.), Karolinska University Hospital, Stockholm, Sweden Departments of Clinical Neurosciences (F.L., O.F.).
authors.forename: O
authors.initials: O
authors.lastname: Flodmark
authors.affiliation: Women's and Children's Health (L.H., A.-C.E., H.F., B.V.), Karolinska Institute, Stockholm, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Forssberg
authors.affiliation: The Florey Institute of Neuroscience and Mental Health (J.-D.T.), Melbourne, Victoria, Australia Department of Medicine (J.-D.T.), University of Melbourne, Victoria, Australia Centre for the Developing Brain (J.-D.T.) Department of Biomedical Engineering (J.-D.T.), Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom.
authors.forename: J-D
authors.initials: JD
authors.lastname: Tournier
authors.affiliation: Women's and Children's Health (L.H., A.-C.E., H.F., B.V.), Karolinska Institute, Stockholm, Sweden Clinical Neurosciences, Clinical and Experimental Sciences (B.V.), Faculty of Medicine, University of Southampton, Southampton, United Kingdom.
authors.forename: B
authors.initials: B
authors.lastname: Vollmer
mesh_terms: D001930:Brain Injuries / Q000150:complications / Q000473:pathology*; D002547:Cerebral Palsy / Q000209:etiology / Q000473:pathology*; D002648:Child; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D011712:Pyramidal Tracts / Q000473:pathology*