title: Utility of susceptibility-weighted MRI in differentiating Parkinson's disease and atypical parkinsonism.
abstract: BACKGROUND
  Neuropathological studies report varying patterns of brain mineralization in Parkinson's diseases (PD), progressive supranuclear palsy (PSP), and Parkinson variant of multiple system atrophy (MSA-P). Susceptibility-weighted imaging (SWI) is the ideal magnetic resonance imaging (MRI) technique to detect mineralization of the brain. The purpose of this study was to test if SWI can differentiate PD, PSP, and MSA-P.
  
  
  METHODS
  Eleven patients with PD, 12 with PSP, 12 with MSA-P, and 11 healthy controls underwent SWI of the brain. Hypointensity of putamen, red nucleus, substantia nigra, and dentate nucleus in all groups were measured using an objective grading scale and scored from 0 to 3.
  
  
  RESULTS
  In PSP, hypointensity score of red nucleus was higher than that in MSA-P (p=0.001) and PD (p=0.001), and a score of ≥ 2 differentiated the PSP group from the PD and MSA-P groups. Putaminal hypointensity score was higher in PSP when compared to that in PD (p=0.003), and a score of ≥ 2 differentiated PSP from PD groups. SWI hypointensity scores of red nucleus and putamen had an excellent intrarater and interrater correlation. Substantia nigra hypointensity score of the PSP group was higher than that of the MSA-P (p=0.004) and PD (p=0.006) groups, but the scores had only a moderate intrarater and interrater correlation.
  
  
  CONCLUSIONS
  SWI shows different patterns of brain mineralization in clinically diagnosed groups of PD, PSP, and MSA-P and may be considered as an additional MR protocol to help differentiate these conditions.
authors.affiliation: Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum, 695011, Kerala, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Gupta
authors.forename: Jitender
authors.initials: J
authors.lastname: Saini
authors.forename: Chandrasekharan
authors.initials: C
authors.lastname: Kesavadas
authors.forename: P Sankara
authors.initials: PS
authors.lastname: Sarma
authors.forename: Asha
authors.initials: A
authors.lastname: Kishore
mesh_terms: D001921:Brain / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity