title: Imaging brain iron and diffusion patterns: a follow-up study of Parkinson's disease in the initial stages.
abstract: OBJECTIVE
  The aim of this study was to examine changes of brain iron content and diffusion patterns longitudinally in early-stage Parkinson's disease (PD) patients using T2- and T2*-based magnetic resonance imaging (MRI) over 2-year follow-up.
  
  
  METHODS
  We imaged 32 PD patients with tremor and 19 healthy controls. A follow-up study (median 25 months, range 22-31 months) was accomplished for 25 patients (men:women = 11:14; age range 44-87 years, median 73 years). All patients and healthy volunteers underwent clinical, neuropsychological, and MRI examinations on the same day. Three different MRI sequences were used and their results were compared: T2-weighted imaging, susceptibility-weighted imaging, and T2* mapping. Additionally, we evaluated diffusion tensor data between groups using tract-based spatial statistics.
  
  
  RESULTS
  Over the 2-year follow-up, the iron-related relaxation increased in the globus pallidus anterior and the caudate nucleus and slightly in the substantia nigra pars compacta (SNc). In the globus pallidus anterior and medial SNc, the change was associated with mild cognitive impairment. In the caudate nucleus, the increase was pronounced in patients with disease onset at 67 years or older. In the SNc, medial transverse relaxation was increased, and in the thalamus, it was decreased, in patients with PD compared with healthy volunteers at 2-year follow-up. Tract-based spatial statistical data did not differ between groups based on gender or Unified Parkinson's Disease Rating Scale, but a slight tendency to decreasing fractional anisotropy (P < .10) in the genu of corpus callosum and bilaterally in corona radiata was seen over 2 years.
  
  
  CONCLUSIONS
  PD-related changes were found in putative iron content over 2 years. Although mild in the initial stages, these changes were consistent over MRI sequences. Rather than correlating with disease duration, the rate of changes was associated with individual characters, such as cognitive decline and age.
authors: Department of Radiology, Medical Imaging Centre, Tampere University Hospital, Teiskontie 35, Post Box 2000, 33520 Tampere, Finland. Electronic address: maija.rossi@hotmail.com.
authors: Maija Elina
authors: ME
authors: Rossi
authors: Department of Neurology and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors: Hanna
authors: H
authors: Ruottinen
authors: Department of Neurology and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors: Tiia
authors: T
authors: Saunamäki
authors: Department of Neurology and Rehabilitation, Tampere University Hospital, Tampere, Finland; Tampere Medical School, University of Tampere, Tampere, Finland.
authors: Irina
authors: I
authors: Elovaara
authors: Department of Radiology, Medical Imaging Centre, Tampere University Hospital, Teiskontie 35, Post Box 2000, 33520 Tampere, Finland; Tampere Medical School, University of Tampere, Tampere, Finland.
authors: Prasun
authors: P
authors: Dastidar
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D002421:Caudate Nucleus / Q000378:metabolism; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D042241:Early Diagnosis; D005260:Female; D005500:Follow-Up Studies; D005917:Globus Pallidus / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013788:Thalamus / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D015415:Biomarkers; D007501:Iron
keywords: Brain iron; Parkinson's disease; diffusion tensor imaging; magnetic resonance imaging