title: Assessment of global and regional diffusion changes along white matter tracts in parkinsonian disorders by MR tractography.
abstract: OBJECTIVE
  The aim of the study was to determine the usefulness of diffusion tensor tractography (DTT) in parkinsonian disorders using a recently developed method for normalization of diffusion data and tract size along white matter tracts. Furthermore, the use of DTT in selected white matter tracts for differential diagnosis was assessed.
  
  
  METHODS
  We quantified global and regional diffusion parameters in major white matter tracts in patients with multiple system atrophy (MSA), progressive nuclear palsy (PSP), idiopathic Parkinson's disease (IPD) and healthy controls). Diffusion tensor imaging data sets with whole brain coverage were acquired at 3 T using 48 diffusion encoding directions and a voxel size of 2×2×2 mm(3). DTT of the corpus callosum (CC), cingulum (CG), corticospinal tract (CST) and middle cerebellar peduncles (MCP) was performed using multiple regions of interest. Regional evaluation comprised projection of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and the apparent area coefficient (AAC) onto a calculated mean tract and extraction of their values along each structure.
  
  
  RESULTS
  There were significant changes of global DTT parameters in the CST (MSA and PSP), CC (PSP) and CG (PSP). Consistent tract-specific variations in DTT parameters could be seen along each tract in the different patient groups and controls. Regional analysis demonstrated significant changes in the anterior CC (MD, RD and FA), CST (MD) and CG (AAC) of patients with PSP compared to controls. Increased MD in CC and CST, as well as decreased AAC in CG, was correlated with a diagnosis of PSP compared to IPD.
  
  
  CONCLUSIONS
  DTT can be used for demonstrating disease-specific regional white matter changes in parkinsonian disorders. The anterior portion of the CC was identified as a promising region for detection of neurodegenerative changes in patients with PSP, as well as for differential diagnosis between PSP and IPD.
authors.affiliation: Department of Clinical Sciences, Neurology, Lund University, Lund, Sweden. yulia.surova@med.lu.se
authors.forename: Yulia
authors.initials: Y
authors.lastname: Surova
authors.forename: Filip
authors.initials: F
authors.lastname: Szczepankiewicz
authors.forename: Jimmy
authors.initials: J
authors.lastname: Lätt
authors.forename: Markus
authors.initials: M
authors.lastname: Nilsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Eriksson
authors.forename: Alexander
authors.initials: A
authors.lastname: Leemans
authors.forename: Oskar
authors.initials: O
authors.lastname: Hansson
authors.forename: Danielle
authors.initials: D
authors.lastname: van Westen
authors.forename: Christer
authors.initials: C
authors.lastname: Nilsson
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D020734:Parkinsonian Disorders / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity