Measurement of the adult human midbrain with transcranial ultrasound.

Rezzak Yilmaz,Verity Pearson-Dennett,Daniela Berg,Gabrielle Todd,Jordi Perez-Tur,Karl Aoun,Kay L Double

doi:10.1371/journal.pone.0247920

Rezzak Yilmaz, Verity Pearson-Dennett + Show 5 more

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https://doi.org/10.1371/journal.pone.0247920

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Abstract

BackgroundTranscranial sonography is increasingly used to aid clinical diagnoses of movement disorders, for example, to identify an enlarged area of substantia nigra echogenicity in patients with Parkinson’s disease.ObjectiveThe current study investigated characteristics of the midbrain at the anatomical plane for quantification of substantia nigra echogenicity. METHODS: Area of substantia nigra echogenicity, cross-sectional area of the midbrain, and interpeduncular angle were quantified in two groups of adults aged 18–50 years: 47 healthy non-drug-using controls (control group) and 22 individuals with a history of methamphetamine use (methamphetamine group), a cohort with a high prevalence of enlarged substantia nigra echogenicity and thus risk of Parkinson’s disease.ResultsIn the control group, cross-sectional area of the midbrain (4.47±0.44 cm2) and interpeduncular angle were unaffected by age, sex, or image acquisition side. In the methamphetamine group, cross-sectional midbrain area (4.72±0.60 cm2) and area of substantia nigra echogenicity were enlarged compared to the control group, and the enlargement was sex-dependent (larger in males than females). Whole midbrain area and interpeduncular angle were found to be weak predictors of area of substantia nigra echogenicity after accounting for group and sex.ConclusionsHistory of methamphetamine use is associated with an enlarged midbrain and area of substantia nigra echogenicity, and the abnormality is more pronounced in males than females. Thus, males may be more susceptible to methamphetamine-induced changes to the brainstem, and risk of Parkinson’s disease, than females.

Highlights

Transcranial sonography can be used to investigate the echogenic appearance of the substantia nigra (SN) [1], a midbrain structure that is challenging to visualize with other imaging modalities
Cross-sectional midbrain area (4.72±0.60 cm2) and area of substantia nigra echogenicity were enlarged compared to the control group, and the enlargement was sex-dependent
History of methamphetamine use is associated with an enlarged midbrain and area of substantia nigra echogenicity, and the abnormality is more pronounced in males than females

Summary

Introduction

Transcranial sonography can be used to investigate the echogenic appearance of the substantia nigra (SN) [1], a midbrain structure that is challenging to visualize with other imaging modalities. The data suggest that an enlarged area of SN echogenicity is a risk marker of PD Widespread adoption of this risk marker in clinical practice is limited by several factors, including, for example, operator dependency, differing quality of the pre-auricular acoustic bone window between patients [8], and differing image resolution between ultrasound machines and manufacturers such that normative data from one machine is not comparable to that of another. This is problematic given that the threshold value for abnormal area of SN echogenicity is based on normative data (e.g. 90th percentile) [8, 9]. This ratio is significantly larger in PD patients compared to healthy controls [11], suggesting the enlarged area of SN echogenicity in PD is not due to an enlarged midbrain

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