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Parkinsonism & Related Disorders Sep 2017Studies have suggested that the majority of patients with Parkinson's disease have abnormal ultrasound hyperechogenicity of the substantia nigra, and that this may be... (Review)
Review
Studies have suggested that the majority of patients with Parkinson's disease have abnormal ultrasound hyperechogenicity of the substantia nigra, and that this may be useful in diagnosis. We performed a systematic review and meta-analysis to evaluate diagnostic value of substantia nigra ultrasound to differentiate Parkinson's disease from atypical parkinsonism and from essential tremor. We systematically searched PubMed and EMBASE for relevant studies published until November 2016. Eligible articles were screened, data were extracted and study quality was scored by two independent reviewers. We applied random effect models to calculate pooled estimates for the prevalence of hyperechogenicity in each condition. For final meta-analysis, 71 articles with a total number of 5730 participants (idiopathic Parkinson's disease: 4494, atypical parkinsonism: 594, essential tremor: 642) were included. The pooled prevalence rate of hyperechogenicity was 84% (95 %CI 80-87%) in idiopathic Parkinson's disease, 28% (95% CI 20-36%) in atypical parkinsonism and 15% (95% CI 7-23%) in essential tremor. Based on our meta-analysis, substantia nigra hyperechogenecity has 75% (95% CI: 60-86%) sensitivity and 70% (95% CI: 55-81%) specificity to differentiate idiopathic Parkinson's disease from atypical parkinsonism. Sensitivity and specificity to distinguish idiopathic Parkinson's disease from essential tremor was calculated as 78% (95% CI: 69-85%) and 85% (95% CI: 77-91%), respectively. Findings from our meta-analysis showed that transcranial sonography can provide useful information to differentiate idiopathic Parkinson's disease from mimicking movement disorders, although sensitivity and specificity are suboptimal, particularly for differentiating from atypical parkinsonism.
Topics: Databases, Bibliographic; Diagnosis, Differential; Essential Tremor; Humans; Parkinson Disease; Substantia Nigra; Ultrasonography, Doppler, Transcranial
PubMed: 28647434
DOI: 10.1016/j.parkreldis.2017.06.006 -
European Radiology Jun 2017Our goal was to estimate the diagnostic accuracy of substantia nigra fractional anisotropy (SN-FA) for Parkinson's disease (PD) diagnosis in a sample similar to the... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Our goal was to estimate the diagnostic accuracy of substantia nigra fractional anisotropy (SN-FA) for Parkinson's disease (PD) diagnosis in a sample similar to the clinical setting, including patients with essential tremor (ET) and healthy controls (HC). We also performed a systematic review and meta-analysis to estimate mean change in SN-FA induced by PD and its diagnostic accuracy.
METHODS
Our sample consisted of 135 subjects: 72 PD, 21 ET and 42 HC. To address inter-scanner variability, two 3.0-T MRI scans were performed. MRI results of this sample were pooled into a meta-analysis that included 1,432 subjects (806 PD and 626 HC). A bivariate model was used to evaluate diagnostic accuracy measures.
RESULTS
In our sample, we did not observe a significant effect of disease on SN-FA and it was uninformative for diagnosis. The results of the meta-analysis estimated a 0.03 decrease in mean SN-FA in PD relative to HC (CI: 0.01-0.05). However, the discriminatory capability of SN-FA to diagnose PD was low: pooled sensitivity and specificity were 72 % (CI: 68-75) and 63 % (CI: 58-70), respectively. There was high heterogeneity between studies (I = 91.9 %).
CONCLUSIONS
SN-FA cannot be used as an isolated measure to diagnose PD.
KEY POINTS
• SN-FA appears insufficiently sensitive and specific to diagnose PD. • Radiologists must be careful when translating mean group results to clinical practice. • Imaging protocol and analysis standardization is necessary for developing reproducible quantitative biomarkers.
Topics: Aged; Anisotropy; Biomarkers; Female; Humans; Magnetic Resonance Imaging; Male; Parkinson Disease; ROC Curve; Sensitivity and Specificity; Substantia Nigra
PubMed: 27709279
DOI: 10.1007/s00330-016-4611-0 -
Scientific Reports Feb 2016A large number of articles have reported substantia nigra hyperechogenicity in Parkinson's disease (PD) and have assessed the diagnostic accuracy of transcranial... (Meta-Analysis)
Meta-Analysis Review
A large number of articles have reported substantia nigra hyperechogenicity in Parkinson's disease (PD) and have assessed the diagnostic accuracy of transcranial sonography (TCS); however, the conclusions are discrepant. Consequently, this systematic review and meta-analysis aims to consolidate the available observational studies and provide a comprehensive evaluation of the clinical utility of TCS in PD. Totally, 31 studies containing 4,386 participants from 13 countries were included. A random effects model was utilized to pool the effect sizes. Meta-regression and sensitivity analysis were performed to explore potential heterogeneity. Overall diagnostic accuracy of TCS in differentiating PD from normal controls was quite high, with a pooled sensitivity of 0.83 (95% CI: 0.81-0.85) and a pooled specificity of 0.87 (95% CI: 0.85-0.88). The positive likelihood ratio, the negative likelihood ratio and diagnostic odds ratio were calculated 6.94 (95% CI: 5.09-9.48), 0.19 (95% CI: 0.16-0.23), and 42.89 (95% CI: 30.03-61.25) respectively. Our systematic review of the literature and meta-analysis suggest that TCS has high diagnostic accuracy in the diagnosis of PD when compared to healthy control.
Topics: Humans; Parkinson Disease; Publication Bias; ROC Curve; Reproducibility of Results; Substantia Nigra; Ultrasonography, Doppler, Transcranial
PubMed: 26878893
DOI: 10.1038/srep20863 -
Neuroradiology Feb 2015Neuroimaging techniques including structural magnetic resonance imaging (MRI) and functional positron emission tomography (PET) are useful in categorizing various... (Review)
Review
PURPOSE
Neuroimaging techniques including structural magnetic resonance imaging (MRI) and functional positron emission tomography (PET) are useful in categorizing various midbrain-hindbrain (MHB) malformations, both in allowing diagnosis and in helping to understand the developmental processes that were disturbed. Brain imaging phenotypes of numerous malformations are characteristic features that help in guiding the genetic testing in case of direct neuroimaging-genotype correlation or, at least, to differentiate among MHB malformations entities. The present review aims to provide the reader with an update of the use of neuroimaging applications in the fine analysis of MHB malformations, using a comprehensive, recently proposed developmental and genetic classification.
METHODS
We have performed an extensive systematic review of the literature, from the embryology main steps of MHB development through the malformations entities, with regard to their molecular and genetic basis, conventional MRI features, and other neuroimaging characteristics.
RESULTS
We discuss disorders in which imaging features are distinctive and how these features reflect the structural and functional impairment of the brain.
CONCLUSION
Recognition of specific MRI phenotypes, including advanced imaging features, is useful to recognize the MHB malformation entities, to suggest genetic investigations, and, eventually, to monitor the disease outcome after supportive therapies.
Topics: Humans; Magnetic Resonance Imaging; Mesencephalon; Nervous System Malformations; Neuroimaging; Rhombencephalon
PubMed: 25339235
DOI: 10.1007/s00234-014-1431-2