title: MRI evaluation of asymmetry of nigrostriatal damage in the early stage of early-onset Parkinson's disease.
abstract: BACKGROUND
  The motor symptoms and signs of early-onset idiopathic Parkinson's disease (PD) in Hoehn and Yahr (H&Y) stage-1 are generally unilateral. We hypothesized that there would be detectable differences in the quantitative MRI parameters in these PD patients between the hemispheres contralateral to the clinically symptomatic and non-symptomatic body side.
  
  
  METHODS
  We tested this hypothesis by comparing transverse relaxation rates and diffusion tensor imaging (DTI) parameters in the substantia nigra and putamen between the two hemispheres contralateral to the symptomatic and non-symptomatic side in H&Y stage-1 PD patients who had onset of symptoms between ages of 40-59 years.
  
  
  RESULTS
  There were quantifiable hemispheric asymmetries in transverse relaxation rates in the substantia nigra, as well as fractional anisotropy and mean diffusivity in the putamen in early PD, which correlated with the unilaterality of motor symptoms as evaluated using the motor portion of the Unified Parkinson's Disease Rating Scale.
  
  
  CONCLUSIONS
  Transverse relaxation mapping and DTI demonstrated significant differences between the symptomatic and non-symptomatic hemispheres at the early stage of early-onset PD. These findings support the hypothesis of asymmetric neurodegeneration in the bilateral nigrostriatal pathways in the early stage of the disease.
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA. Electronic address: jxw73@psu.edu.
authors.forename: Jianli
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA; Department of Neurosurgery, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Qing X
authors.initials: QX
authors.lastname: Yang
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Vesek
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Mosher
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Megha
authors.initials: M
authors.lastname: Vasavada
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chu
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Sangam
authors.initials: S
authors.lastname: Kanekar
authors.affiliation: Department of Neurology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Vikram
authors.initials: V
authors.lastname: Shivkumar
authors.affiliation: Department of Neurology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Kala
authors.initials: K
authors.lastname: Venkiteswaran
authors.affiliation: Department of Neurology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA; Department of Neural & Behavioral Sciences, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA.
authors.forename: Thyagarajan
authors.initials: T
authors.lastname: Subramanian
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D042241:Early Diagnosis; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D011699:Putamen / Q000473:pathology*; D013378:Substantia Nigra / Q000473:pathology*
keywords: Asymmetry; Diffusion tensor imaging; Parkinson's disease; Putamen; Substantia nigra; Transverse relaxation rate