Assessment of substantia nigra echogenicity in German and Filipino populations using a portable ultrasound system.
OBJECTIVE
Transcranial sonography of the substantia nigra for diagnosing premotor stages of Parkinson disease has been attracting increasing interest. Standard reference values defining an abnormal increased echogenic size (hyperechogenicity) of the substantia nigra have been established in several populations using high-end stationary ultrasound systems. It is unknown whether a portable ultrasound system can be appropriately used and how the Filipino population would compare with the well-studied white population.


METHODS
We prospectively studied substantia nigra echogenic sizes and third ventricle widths in 71 healthy adult German participants and 30 age- and sex-matched Filipino participants using both a well-established stationary ultrasound system (in the German cohort) and a recently distributed portable ultrasound system (in both ethnic cohorts).


RESULTS
Mean substantia nigra echogenic sizes, cutoff values defining abnormal hyperechogenicity, and intra-rater reliability were similar with both systems and in both ethnic cohorts studied. The Filipino and German participants did not differ with respect to the frequency of insufficient insonation conditions (each 3%) and substantia nigra hyperechogenicity (10% versus 9%; P = .80). However, third ventricle widths were smaller in the Filipino than the German participants (mean ± SD, 1.6 ± 1.1 versus 2.4 ± 1.0 mm; P = .004).


CONCLUSIONS
The frequency of substantia nigra hyperechogenicity appears to be homogeneous in white and Asian populations. Screening for this feature may well be performed with a present-day portable ultrasound system.
Department of Neurology, University of Rostock, Gehlsheimer Strasse 20, D-18147 Rostock, Germany.
Criscely L
CL
Go
Antonia
A
Frenzel
Raymond L
RL
Rosales
Lillian V
LV
Lee
Reiner
R
Benecke
Dirk
D
Dressler
Uwe
U
Walter
D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000208:ethnology*; D010679:Philippines; D019095:Point-of-Care Systems; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013378:Substantia Nigra / Q000000981:diagnostic imaging*; D011795:Surveys and Questionnaires; D017585:Ultrasonography, Doppler, Transcranial / Q000295:instrumentation*