title: Brain parenchyma sonography discriminates Parkinson's disease and atypical parkinsonian syndromes.
abstract: OBJECTIVE
  To study the use of brain parenchyma sonography (BPS) in discriminating between patients with idiopathic PD (IPD) and atypical parkinsonian syndromes (APS).
  
  
  METHODS
  Twenty-five patients with APS, 9 with progressive supranuclear palsy (PSP) and 16 with multiple-system atrophy (MSA), and 25 age-matched patients with IPD were prospectively studied with BPS according to a standardized protocol.
  
  
  RESULTS
  Twenty-four of the 25 (96%) IPD patients exhibited hyperechogenicity of the substantia nigra (SN) but only 2 of 23 (9%) APS patients (Mann-Whitney U test, p < 0.001). In those two APS patients, SN hyperechogenicity was moderate only, whereas the remaining 21 APS patients had normal SN echogenicity. The specificity of SN hyperechogenicity in detection of clinically diagnosed IPD patients was 96%, and the sensitivity was 91%. If SN hyperechogenicity was marked, APS could be excluded because of a positive predictive value of 100% for IPD. Nucleus lentiformis hyperechogenicity was found in 17 of 22 (77%) APS patients but in only 5 of 22 (23%) IPD patients (Mann-Whitney U test, p < 0.001). Nucleus caudatus and thalamus echogenicity and widths of the third ventricle and of the frontal horns of the lateral ventricles did not discriminate between IPD and APS. Two patients with PSP could not be assessed because of an insufficient bone window.
  
  
  CONCLUSIONS
  BPS is a novel and noninvasive method to differentiate highly specifically between IPD and APS. Therefore, BPS might become a standard investigation in parkinsonian disorders.
authors.affiliation: Department of Neurology, Rostock University, Germany. uwe.walter@med.uni-rostock.de
authors.forename: U
authors.initials: U
authors.lastname: Walter
authors.forename: L
authors.initials: L
authors.lastname: Niehaus
authors.forename: T
authors.initials: T
authors.lastname: Probst
authors.forename: R
authors.initials: R
authors.lastname: Benecke
authors.forename: B U
authors.initials: BU
authors.lastname: Meyer
authors.forename: D
authors.initials: D
authors.lastname: Dressler
mesh_terms: D000368:Aged; D003342:Corpus Striatum / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004453:Echoencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis* / Q000000981:diagnostic imaging; D010300:Parkinson Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013378:Substantia Nigra / Q000000981:diagnostic imaging; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013701:Temporal Bone / Q000000981:diagnostic imaging