Introduction: We aimed to evaluate whether neuromelanin-sensitive MRI (NM-MRI) features in the substantia nigra pars compacta (SNc) were of diagnostic value to differentiate untreated essential tremor (ET) from de novo tremor-dominant Parkinson's disease (PD T ). Methods: Eighteen untreated ET patients, 21 de novo PD T patients and 21 healthy control subjects were recruited. All the subjects underwent clinical examination, motor and cognitive evaluations, as well as NM-MRI. High signal intensity of the lateral, central and medial SNc subregions on NM-MRI were evaluated using the width, signal intensity (contrast-to-noise ratio, CNR) and visual analysis. Diagnostic test performance of SNc values was investigated by using receiver operating characteristic analysis and net reclassification improvement (NRI). Results: The width and CNR values of the lateral and central SNc subregions in PD T were significantly decreased compared with those in ET and control group. Using visual analysis, the total visual score of all SNc subregions was significantly reduced in PD T when compared with ET and control group. The width of the lateral SNc subregion allowed the best differentiation between ET and PD T , and visual analysis also showed good diagnostic value. NRI result indicated that visual analysis and the width of the lateral SNc subregion had the same diagnostic power. Conclusions: The neuromelanin changes of SNc in ET and PD T follow the different patterns. Both the measurements and visual analysis of SNc on NM-MRI provide high diagnostic accuracy for differentiating ET from PD T subtype. NM-MRI is a potential tool in diagnostic work-up of tremor disorders.
Wang, J., Huang, Z., Li, Y., Ye, F., Wang, C., Zhang, Y., … Jin, L. (2019). Neuromelanin-sensitive MRI of the substantia nigra: An imaging biomarker to differentiate essential tremor from tremor-dominant Parkinson’s disease. Parkinsonism and Related Disorders, 58, 3–8. https://doi.org/10.1016/j.parkreldis.2018.07.007