title: Substantia nigra echogenicity is correlated with nigrostriatal impairment in Machado-Joseph disease.
abstract: BACKGROUND
  Several studies have demonstrated increased substantia nigra (SN) echogenicity in Parkinson's disease (PD) and Machado-Joseph disease (MJD). Pathological substrate of PD is characterized by dopaminergic nigrostriatal cell loss, also found in MJD. Also, SN hyperechogenicity might be associated with nigrostriatal dysfunction in PD, when comparing dopamine transporter binding with SN echogenicity. The present study aimed to correlate the SN echogenic size and striatal dopamine transporter density in MJD patients.
  
  
  METHODS
  We performed TCS in 30 subjects and SPECT with [(99m)Tc]-TRODAT-1 in 18 subjects with MJD. Fifteen healthy subjects matched for age and gender formed a control group. TCS and [(99m)Tc]-TRODAT-1 SPECT findings from both MJD patients and control subjects were compared.
  
  
  RESULTS
  There were no differences regarding age (p = 0.358) or gender (p = 0.566) between groups (MJD versus control group). Mean DAT binding potentials and SN echogenicity were significantly different between groups. There was a significant negative correlation with regard to the SN echogenic size and the ipsilateral striatal TRODAT-1 uptake: the higher the SN echogenicity, the lower the DAT uptake in the ipsilateral cerebral hemisphere.
  
  
  CONCLUSIONS
  Increase in SN echogenic size likely correlates with presynaptic dopaminergic nigrostriatal dysfunction in MJD, suggesting a concurrent in vivo pathophysiological mechanism.
authors.affiliation: Department of Neurology, Ataxia Unit, Universidade Federal de São Paulo, Rua Botucatu, 740, São Paulo 04.023-900, SP, Brazil. jlpedroso.neuro@gmail.com
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Pedroso
authors.forename: Edson
authors.initials: E
authors.lastname: Bor-Seng-Shu
authors.forename: André C
authors.initials: AC
authors.lastname: Felício
authors.forename: Pedro
authors.initials: P
authors.lastname: Braga-Neto
authors.forename: Marcelo Q
authors.initials: MQ
authors.lastname: Hoexter
authors.forename: Manoel Jacobsen
authors.initials: MJ
authors.lastname: Teixeira
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Orlando Graziani Povoas
authors.initials: OG
authors.lastname: Barsottini
mesh_terms: D000328:Adult; D003342:Corpus Striatum / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D017827:Machado-Joseph Disease / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013378:Substantia Nigra / Q000000981:diagnostic imaging*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods