Echogenicity of the substantia nigra region in Parkinson's disease

Hospital das Clinicas, University of Sao Paulo School of Medicine (FMUSP), Sao Paulo, Brazil. Correspondence: Edson Bor-Seng-Shu; Divisao de Cirurgia Neurologica, Hospital das Clinicas, USP; Avenida Dr. Eneas de Carvalho Aguiar 255; 05403-000 Sao Paulo SP Brasil; E-mail: edsonshu@hotmail.com Conflict of interest: There is no conflict of interest to declare. Received 04 September 2011; Received in final form 14 September 2011; Accepted 21 September 2011