title: Sonography for diagnosis of Parkinson disease-from theory to practice: a study on 300 participants.
abstract: OBJECTIVE
  Hyperechogenicity of the substantia nigra on transcranial sonography is used for diagnosing Parkinson disease (PD). Cutoff values for the substantia nigra echogenic area, defining substantia nigra hyperechogenicity, vary among ultrasound systems from different manufacturers. In this study we wanted to determine the cutoff criterion for a Toshiba (Tokyo, Japan) system and to assess its diagnostic value.
  
  
  METHODS
  Three hundred participants (controls, n = 138; patients with PD, n = 105; and patients with essential tremor, n = 57) underwent transcranial sonography following a standardized protocol.
  
  
  RESULTS
  The substantia nigra was assessable in 92.7% of all participants. The substantia nigra echogenic area (larger of bilateral measurements) was larger in patients with PD (mean ± SD, 0.24 ± 0.05 cm(2)) than controls (0.14 ± 0.05 cm(2); P < .001) and patients with essential tremor (0.14 ± 0.04 cm(2); P < .001). Substantia nigra echogenicity was larger in male participants (0.20 ± 0.07 cm(2)) than female participants (0.15 ± 0.06 cm(2); P< .001). Age did not correlate with substantia nigra echogenicity in any group. Frontal horn width was larger and lenticular nucleus hyperechogenicity and a discontinuous raphe were more frequent in the PD group than the other groups. On multivariate analysis, only substantia nigra hyperechogenicity was associated with the diagnosis of PD. The 90th-percentile substantia nigra echogenic area in the control group, which defined marked substantia nigra hyperechogenicity, also represented the optimum cutoff value for discrimination of PD from non-PD participants on receiver operating characteristic curve analysis (area under the curve, 0.913; Youden index, 0.73). This cutoff value (≥0.21 cm(2), larger of bilateral measurements) yielded sensitivity of 83% and specificity of 90% for the diagnosis of PD.
  
  
  CONCLUSIONS
  Transcranial sonography shows good diagnostic validity for diagnosis of PD when implemented according to a strictly standardized protocol.
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.). aracelialonsocanovas@gmail.com.
authors.forename: Araceli
authors.initials: A
authors.lastname: Alonso-Cánovas
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: José Luis
authors.initials: JL
authors.lastname: López-Sendón
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Javier
authors.initials: J
authors.lastname: Buisán
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Alicia
authors.initials: A
authors.lastname: deFelipe-Mimbrera
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Marta
authors.initials: M
authors.lastname: Guillán
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Nuria
authors.initials: N
authors.lastname: García-Barragán
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Iñigo
authors.initials: I
authors.lastname: Corral
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: María Consuelo
authors.initials: MC
authors.lastname: Matute-Lozano
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Jaime
authors.initials: J
authors.lastname: Masjuan
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Martínez-Castrillo
authors.affiliation: Department of Neurology, Ramón y Cajal University Hospital, Madrid, Spain (A.A.-C., J.L.L.-S., J.B., A.d.-M., M.G., N.G.-B., I.C., M.C.M.-L., J.M., J.C.M.-C.); and Department of Neurology, University of Rostock, Rostock, Germany (U.W.).
authors.forename: Uwe
authors.initials: U
authors.lastname: Walter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005060:Europe; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods / Q000592:standards*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D017410:Practice Guidelines as Topic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013378:Substantia Nigra / Q000000981:diagnostic imaging*; D017585:Ultrasonography, Doppler, Transcranial / Q000592:standards* / Q000706:statistics & numerical data*
keywords: Parkinson disease; basal ganglia echogenicity; diagnosis; essential tremor; midbrain transcranial sonography; neurosonology; substantia nigra