title: Transcranial sonography for diagnosis of Parkinson's disease.
abstract: BACKGROUND
  In idiopathic Parkinson's disease (IPD) transcranial sonography (TCS) represents an alternative diagnostic method to verify clinical diagnosis. Although the phenomenon of an increased echogenicity of the Substantia nigra (SN) is well known this method is still not widly used in the diagnostic workup. Until now reliability of this method is still a matter of debate, partly because data only existed from a few laboratories using the same ultrasound machine. Therefore our study was conducted to test the reliability of this method by using a different ultrasound device and examining a large population of control and IPD subjects by two examiners to calculate interobserver reliability.
  
  
  METHODS
  In this study echogenicity of SN was examined in 199 IPD patients and 201 control subjects. All individuals underwent a neurological assessment including Perdue pegboard test and Webster gait test. Using a Sonos 5500 ultrasound device area of SN was measured, echogenicity of raphe, red nuclei, thalamus, caudate and lenticular nuclei, width of third and lateral ventricle were documented.
  
  
  RESULTS
  We found a highly characteristic enlargement of the SN echogenic signal in IPD. The cut-off value for the SN area was established using a ROC curve with a sensitivity of 95% corresponding to an area of SN of 0.2 cm2 and was found to be equivalent to the cut-off values of other studies using different ultrasound devices.
  
  
  CONCLUSIONS
  Our study shows that TCS is a reliable and highly sensitive tool for differentiation of IPD patients from individuals without CNS disorders.
authors.affiliation: Department of Neurology, Justus-Liebig University of Giessen, Giessen, Germany. sabine.schmidt@neuro.med.uni-giessen.de
authors.forename: Sabine
authors.initials: S
authors.lastname: Mehnert
authors.forename: Iris
authors.initials: I
authors.lastname: Reuter
authors.forename: Karsten
authors.initials: K
authors.lastname: Schepp
authors.forename: Peter
authors.initials: P
authors.lastname: Maaser
authors.forename: Erwin
authors.initials: E
authors.lastname: Stolz
authors.forename: Manfred
authors.initials: M
authors.lastname: Kaps
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001921:Brain / Q000473:pathology; D004453:Echoencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult