title: Nigrosome-1 on Susceptibility Weighted Imaging to Differentiate Parkinson's Disease From Atypical Parkinsonism: An In Vivo and Ex Vivo Pilot Study.
abstract: BACKGROUND
  Previous case-control studies have suggested that the absence of a swallow-tail appearance in the substantia nigra on high-resolution SWI, representing nigrosome-1, has high accuracy to identify Parkinson's disease (PD). The first goal of our study was to evaluate nigrosome-1 ex vivo using optimized high-resolution susceptibility sensitive MRI. Our second goal was to evaluate its diagnostic value in vivo using a clinical 3T SWI sequence to differentiate between PD and atypical parkinsonism (AP) in a cohort of patients with early-stage parkinsonism.
  
  
  METHODS
  Case-control pilot study to evaluate nigrosome-1 ex vivo (2 PD, 2 controls), using high-resolution susceptibility sensitive sequences at 11.7 T MRI. Next, evaluation of nigrosome-1 in vivo using a clinical 3 T SWI sequence in a prospective cohort of 60 patients with early-stage parkinsonism (39 PD, 21 AP). Moreover, 12 control subjects were scanned. The bilateral substantia nigra was evaluated by two neuroradiologists for the presence, absence or indecisive presence of nigrosome-1. The discriminative power was evaluated by Receiver-Operating Characteristic.
  
  
  RESULTS
  We identified nigrosome-1 in ex vivo control subjects. Nigrosome-1 was not identified in the ex vivo PD cases. In our prospective clinical cohort study, the AUC for the swallow-tail sign to discriminate between PD and AP was 0.56 (0.41-0.71) for reader 1 and 0.68 (0.55-0.82) for reader 2.
  
  
  CONCLUSIONS
  The diagnostic accuracy of the swallow-tail sign was marginal to discriminate between PD and AP using our clinical 3 T SWI sequence.
authors: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Frederick J A
authors: FJ
authors: Meijer
authors: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Stefan C
authors: SC
authors: Steens
authors: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Anouke
authors: A
authors: van Rumund
authors: Department of Anatomy, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Anne-Marie
authors: AM
authors: van Cappellen van Walsum
authors: Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Benno
authors: B
authors: Küsters
authors: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Rianne A J
authors: RA
authors: Esselink
authors: Neurology and Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Marcel M
authors: MM
authors: Verbeek
authors: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Bastiaan R
authors: BR
authors: Bloem
authors: Department of Diagnostic Imaging, Medical Center of Postgraduate Education, Warsaw, Poland.
authors: Bożena
authors: B
authors: Goraj
keywords: Brain Diseases; Magnetic Resonance Imaging; Parkinson Disease; Parkinsonian Disorders