title: Substantia nigra echogenicity in hereditary ataxias with and without nigrostriatal pathology: a pilot study.
abstract: Our objective was to determine whether substantia nigra (SN) hyperechogenicity is greater in spinocerebellar ataxias (SCA) with nigrostriatal affectation than in ataxias without it. A cross-sectional case-control study analyzing four groups of patients was conducted: 1) nigrostriatal ataxias (SCA3 and SCA6), 2) nigrostriatal healthy controls matched by age and sex, 3) non-nigrostriatal ataxias (FRDA and SCA7), and 4) non-nigrostriatal healthy controls matched by age and sex. All the patients underwent a transcranial ultrasound performed by an experienced sonographer blinded to the clinical, genetic, and neuroimaging data. The SN area was measured and compared in the four groups. The SN area was also correlated with clinical features and genetic data in the two ataxia groups. We examined 12 patients with nigrostriatal ataxia (11 SCA3 and 1 SCA6), 12 nigrostriatal healthy control patients, 7 patients with non-nigrostriatal ataxia (5 FRDA and 2 SCA7), and 7 non-nigrostriatal healthy control patients. The median (IQR) SN area (cm(2)) was greater in the nigrostriatal ataxias compared with the controls (right SN, 0.43 [0.44] vs. 0.11 [0.25]; P=0.001; left SN, 0.32 [0.25] vs. 0.11 [0.16]; P=0.001), but was similar among the non-nigrostriatal ataxias and controls. There were no statistically significant differences in the SN area between the nigrostriatal and non-nigrostriatal ataxias, although there was a tendency for a greater left SN area in the nigrostriatal compared with the non-nigrostriatal ataxias (0.32 [0.25] vs. 0.16 [0.24], P=0.083). SN echogenicity is markedly greater in ataxias with nigrostriatal pathology than in controls. The role of SN hyperechogenicity in differentiating ataxias with and without nigrostriatal pathology should be elucidated in future studies.
authors.affiliation: Department of Neurology and Stroke Center, La Paz University Hospital, Autonoma of Madrid University IdiPAZ Health Research Institute, Paseo de la Castellana 261, 28046, Madrid, Spain, patrindalo@hotmail.com.
authors.forename: Patricia
authors.initials: P
authors.lastname: Martínez-Sánchez
authors.forename: Rubén
authors.initials: R
authors.lastname: Cazorla-García
authors.forename: Irene
authors.initials: I
authors.lastname: Sanz-Gallego
authors.forename: Elisa
authors.initials: E
authors.lastname: Correas-Callero
authors.forename: Irene
authors.initials: I
authors.lastname: Pulido-Valdeolivas
authors.forename: Javier
authors.initials: J
authors.lastname: Arpa
mesh_terms: D000328:Adult; D001259:Ataxia / Q000000981:diagnostic imaging / Q000473:pathology*; D016022:Case-Control Studies; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D020754:Spinocerebellar Ataxias / Q000473:pathology; D013132:Spinocerebellar Degenerations / Q000000981:diagnostic imaging / Q000473:pathology*; D013378:Substantia Nigra / Q000000981:diagnostic imaging / Q000473:pathology*; D017585:Ultrasonography, Doppler, Transcranial