Vulnerability of the nigrostriatal system as detected by transcranial ultrasound

Abstract

Substantia nigra hyperechogenicity appears to indicate a functional impairment of the nigrostriatal system. Transcranial sonography may be a suitable method of identifying persons at risk of nigrostriatal alterations, making possible the introduction of early neuroprotective therapy.

Structural abnormality of the substantia nigra in children with attention-deficit hyperactivity disorder

“…Enlarged echogenicity in healthy individuals was associated with impaired uptake of [18F]-dopa in the basal ganglia (assessed by positron emission tomography). 10 Substantia nigra echogenicity was correlated to presynaptic dopaminergic dysfunction elicited by single photon emission computed tomography in patients with Parkinson disease 16 and with the severity of parkinsonism induced by neuroleptics in patients with schizophrenia. 17 However, there is still disagreement about how abnormal extension of substantia nigra echogenicity is related to the pathogenic substrate of Parkinson disease.…”

“…10 An investigator experienced in TCS (M.S. ), who was unaware of the clinical status of the participants, performed the TCS examinations in a random order.…”

Transcranial Sonography (TCS) of Brain Parenchyma in Movement Disorders: Quality Standards, Diagnostic Applications and Novel Technologies

“…The inter-individual variation of SN echogenicity has been suggested to be caused by a variable degree of local iron accumulation and abnormal iron-protein compounds but also by gliotic changes [1, 14,15]. Between the 18 th and 75 th year of age, the distribution of SN echogenicity can be regarded as nearly constant [16,17], even though there are reports of a moderate increase during adult life decades [18], especially after the age of 80 [19]. To rate SN echogenicity in an individual as normal or increased ("hyperechogenic"), the 75 th and 90 th percentile of measures in the normal population are used as a reference [1], and the larger of bilaterally measured SN echogenic sizes is used for classification as follows:…”

“…Marked SN hyperechogenicity is also found in about 10 % of healthy adults and has been associated in them with a (subclinical) malfunction of the nigrostriatal dopaminergic system [1,16]. In a 5-year follow-up study performed in Southern Germany and Austria of 1800 subjects at ages between 50 and 70 years without PD at baseline, SN hyperechogenicity was associated with a 20-fold increased risk of developing PD [27].…”

“…27 Mehnert et al [17] Hagenah et al [18] Siemens/Acuson Antares PX4 -1/2.5 ≥ 0.24 ≥ 0.30 Van de Loo et al [10] Glaser et al [24] Siemens/Sonoline Elegra 2.5PL20/2.6 ≥ 0.20 ≥ 0. 25 Berg et al [16] Toshiba Aplio XG PST-20CT/2.5 ≥ 0.16 ≥ 0.22 Vivo-Orti et al [25] SN-h = substantia nigra hyperechogenicity 1 The cut-off values for the ultrasound systems Siemens Sonoline Elegra, GE Logiq 7, Philips HP Sonos 5500 and Toshiba Aplio XG were obtained by studying large normal populations. With most other TCS systems, the cut-off values were derived from receiver operating characteristic curve analysis of diagnostic discrimination between Parkinson's disease patients and healthy subjects, and/or by direct comparison of two different ultrasound systems in the same study cohort.…”