title: T2* Relaxometry in Patients with Parkinson's Disease : Use of an Automated Atlas-based Approach.
abstract: BACKGROUND
  Magnetic resonance (MR) relaxometry is of increasing scientific relevance in neurodegenerative disorders but is still not established in clinical routine. Several studies have investigated relaxation time alterations in disease-specific areas in Parkinson's disease (PD), all using manually drawn regions of interest (ROI). Implementing MR relaxometry into the clinical setting involves the reduction of time needed for postprocessing using an investigator-independent and reliable approach. The aim of this study was to evaluate an automated, atlas-based ROI method for evaluating T2* relaxation times in patients with PD.
  
  
  METHODS
  Automated atlas-based ROI analysis of quantitative T2* maps were generated from 20 PD patients and 20 controls. To test for the accuracy of the atlas-based ROI segmentation, we evaluated the spatial overlap in comparison with manually segmented ROIs using the Dice similarity coefficient (DSC). Additionally, we tested for group differences using our automated atlas-based ROIs of the putamen, globus pallidus, and substantia nigra.
  
  
  RESULTS
  A good spatial overlap accuracy was shown for the automated segmented putamen (mean DSC, 0.64 ± 0.04) and was inferior but still acceptable for the substantia nigra (mean DSC, 0.50 ± 0.17). Based on our automated defined ROI selection, a significant decrease of T2* relaxation time was found in the putamen as well as in the internal and external globus pallidus in PD patients compared with healthy controls.
  
  
  CONCLUSIONS
  Automated digital brain atlas-based approaches are reliable, more objective and time-efficient, and therefore have the potential to replace the time-consuming manual drawing of ROIs.
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany. karl.egger@uniklinik-freiburg.de.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany. karl.egger@uniklinik-freiburg.de.
authors.forename: Karl
authors.initials: K
authors.lastname: Egger
authors.affiliation: Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.|Department of Neurology, University Medical Center Freiburg, Freiburg, Germany.|BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Amtage
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Shan
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Obmann
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schwarzwald
authors.affiliation: Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.|Department of Neurology, University Medical Center Freiburg, Freiburg, Germany.|BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.|Biological and Personality Psychology, Department of Psychology, University of Freiburg, Freiburg, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Köstering
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Mader
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Koenigsdorf
authors.affiliation: Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.|Department of Neurology, University Medical Center Freiburg, Freiburg, Germany.|BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Weiller
authors.affiliation: Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.|Department of Neurology, University Medical Center Freiburg, Freiburg, Germany.|BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.
authors.forename: Christoph P
authors.initials: CP
authors.lastname: Kaller
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.|Freiburg Brain Imaging Center, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Horst
authors.initials: H
authors.lastname: Urbach
mesh_terms: D001931:Brain Mapping; D005260:Female; D005858:Germany; D005917:Globus Pallidus / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Dice similarity coefficient; Magnetic resonance imaging; Parkinson’s disease; Region of interest; Relaxometry