title: Changes in the thalamus in atypical parkinsonism detected using shape analysis and diffusion tensor imaging.
abstract: OBJECTIVE
  The thalamus is interconnected with the nigrostriatal system and cerebral cortex and has a major role in cognitive function and sensorimotor integration. The purpose of this study was to determine how regional involvement of the thalamus differs among Parkinson disease, progressive supranuclear palsy, and corticobasal syndrome.
  
  
  METHODS
  Nine patients with Parkinson disease, 5 with progressive supranuclear palsy, and 6 with corticobasal syndrome underwent 3T MR imaging along with 12 matched, asymptomatic volunteers by using a protocol that included volumetric T1 and diffusion tensor imaging. Acquired data were automatically processed to delineate the margins of the motor and nonmotor thalamic nuclear groups, and measurements of ADC were calculated from the DTI data within these regions. Thalamic volume, shape, and ADC were compared across groups.
  
  
  RESULTS
  Thalamic volume was smaller in the progressive supranuclear palsy and corticobasal syndrome groups compared with the Parkinson disease and control groups. Shape analysis revealed that this was mainly due to the diminished size of the lateral thalamus. Overall, ADC measurements were higher in the progressive supranuclear palsy group compared with both the Parkinson disease and control groups, and anatomic subgroup analysis demonstrated that these changes were greater within the motor regions of the thalamus in progressive supranuclear palsy and corticobasal degeneration.
  
  
  CONCLUSIONS
  Reduced size and increased ADC disproportionately involve the lateral thalamus in progressive supranuclear palsy and corticobasal syndrome, consistent with selective neurodegeneration and atrophy in this region. Because these findings were not observed in Parkinson disease, they may be more specific markers of tau-related neurodegeneration.
authors.affiliation: From the Departments of Radiology and Biomedical Imaging (C.P.H., A.C.A., W.P.D.) Christopher.Hess@ucsf.edu.
authors.forename: C P
authors.initials: CP
authors.lastname: Hess
authors.affiliation: Neurology (C.W.C., W.P.D., M.J.A.), University of California, San Francisco, San Francisco, California.
authors.forename: C W
authors.initials: CW
authors.lastname: Christine
authors.affiliation: From the Departments of Radiology and Biomedical Imaging (C.P.H., A.C.A., W.P.D.).
authors.forename: A C
authors.initials: AC
authors.lastname: Apple
authors.affiliation: From the Departments of Radiology and Biomedical Imaging (C.P.H., A.C.A., W.P.D.)Neurology (C.W.C., W.P.D., M.J.A.), University of California, San Francisco, San Francisco, California.
authors.forename: W P
authors.initials: WP
authors.lastname: Dillon
authors.affiliation: Neurology (C.W.C., W.P.D., M.J.A.), University of California, San Francisco, San Francisco, California.
authors.forename: M J
authors.initials: MJ
authors.lastname: Aminoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013494:Supranuclear Palsy, Progressive / Q000473:pathology*; D024801:Tauopathies / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*