title: Use of the Putamen/Caudate Volume Ratio for Early Differentiation between Parkinsonian Variant of Multiple System Atrophy and Parkinson Disease.
abstract: OBJECTIVE
  Neuropathological studies have demonstrated that multiple system atrophy (MSA) produces selective atrophy of the putamen with sparing of the caudate nucleus, while both structures are spared in idiopathic Parkinson's disease (PD). In this study we evaluated the clinical efficacy of using putaminal atrophy in brain MRI to differentiate MSA and PD.
  
  
  METHODS
  We measured the putamen/caudate volume ratio on brain MRI in 24 patients with MSA and 21 patients with PD. Two clinicians who were blinded to the patients' diagnoses and to each other's assessments measured the volume ratio using a computer program.
  
  
  RESULTS
  The measured volume ratios of the two investigators were highly correlated (r=0.72, p<0.0001). The volume ratio was significantly lower in MSA (1.29+/-0.28) than PD (1.91+/-0.29, p<0.0001). Setting an arbitrary cutoff ratio of 1.6 resulted in about 90% of patients with MSA falling into the group with a lower ratio, whereas more than 80% of patients with PD belonged to the other group.
  
  
  CONCLUSIONS
  The present results demonstrate that putaminal atrophy in MSA as measured on brain MRI represents an effective tool for differentiating MSA from PD.
authors.affiliation: Department of Neurology and Brain Research Institute, Seoul, Korea.
authors.forename: Ha Y
authors.initials: HY
authors.lastname: Shin
authors.forename: Suk Y
authors.initials: SY
authors.lastname: Kang
authors.forename: Jae H
authors.initials: JH
authors.lastname: Yang
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Kim
authors.forename: Myung-Sik
authors.initials: MS
authors.lastname: Lee
authors.forename: Young H
authors.initials: YH
authors.lastname: Sohn