Lentiform Nucleus Hyperechogenicity in Parkinsonian Syndromes: A Systematic Review and Meta-Analysis with Consideration of Molecular Pathology.

Daniel Richter,Andrei V. Alexandrov,Thomas Müller,George P. Paraskevas,Ralf Gold,Christoph Schroeder,Aristeidis H. Katsanos,Christos Krogias,Lars Tönges,Georgios Tsivgoulis

doi:10.3390/cells9010002

Abstract

The hyperechogenicity of the substania nigra (SN) has been established as a valid finding in patients with Parkinson’s disease (PD), probably caused by an increased tissue iron concentration in the SN. The application of transcranial sonography (TCS) has been investigated for further echogenic basal ganglia alterations in patients with extrapyramidal movement disorders. Compared to PD, a hyperechogenic nucleus lentiformis (LN) has been reported to appear more frequently in atypical parkinsonian syndromes (aPS) such as the parkinsonian phenotype of multiple system atrophy (MSA-P) or the progressive supranuclear palsy (PSP). As the evidence providing study sizes are small, we conduct the first meta-analysis of the prevalence of LN hyperechogenicity in PD and aPS. We search for available studies providing prevalence of LN hyperechogenicity in patients with PD and aPS (MSA-P and PSP) detected by TCS in MEDLINE and SCOPUS databases. We calculate the prevalence rates of LN hyperechogenicity detection in patients with clinical diagnosis of PD vs. aPS under the random-effects model. We include a total of 1330 patients, 1091 PD and 239 aPS (MSA-P and PSP). We find a significantly higher prevalence of LN hyperechogenicity in aPS (76%, 95% CI: 0.62-0.88) compared to PD (16%, 95% CI: 0.10-0.23). After proving a higher prevalence of LN hyperechogenicity in aPS compared to PD, its histopathological cause needs to be investigated. Furthermore, its full diagnostic accuracy and the qualification to serve as a risk factor for MSA-P and PSP should also be questioned in future studies.

Highlights

Transcranial sonography (TCS) in Parkinson’s disease (PD) has been increasingly applied over the last two decades and has proven to be a very helpful tool in the diagnostic process and risk stratification of extrapyramidal movement disorders [1]
LN hyperechogenicity has been considered as a promising marker of atypical parkinsonian syndromes (aPS), the scientific evidence of this observation was based on several studies with only a small number of patients
The literature search in the MEDLINE and SCOPUS databases was performed by two independent reviewers (D.R. and A.H.K.) using the following terms in combination: “nucleus lentiformis”, “basal ganglia”, “transcranial sonography”, “transcranial ultrasound”, “Parkinson”, “multiple system atrophy”, “progressive supranuclear palsy”, “movement disorder”

Summary

Introduction

Transcranial sonography (TCS) in Parkinson’s disease (PD) has been increasingly applied over the last two decades and has proven to be a very helpful tool in the diagnostic process and risk stratification of extrapyramidal movement disorders [1]. Substantia nigra (SN) hyperechogenicity could be identified as a typical finding in patients with idiopathic Parkinson’s disease (PD), allowing a clear distinction between PD and healthy controls [2], while a distinction between idiopathic and atypical parkinsonian syndromes (aPS) is more difficult [3]. Found a prevalence of SN hyperechogenicity in 84% of PD patients and only in 28% of aPS patients. We perform the first meta-analysis to date on LN hyperechogenicity prevalence in PD and aPS

Methods

Results

Conclusion