A longitudinal study of neuromelanin-sensitive magnetic resonance imaging in Parkinson’s disease

• DOI: 10.1016/j.neulet.2016.09.011
• Publication Date: 2016-09-16T07:55:28Z
• Authors: Keita Matsuura; Masayuki Maeda; Ken-ichi Tabei; Maki Umino; Hiroyuki Kajikawa; Masayuki Satoh; Hirotaka Kida; Hidekazu Tomimoto
• Keywords: Neuromelanin; Pars compacta; Rank correlation

Neuromelanin-sensitive MR imaging (NMI) is an increasingly powerful tool for the diagnosis of Parkinson's disease (PD). This study was undertaken to evaluate longitudinal changes on NMI in PD patients.We examined longitudinal changes on NMI in 14 PD patients. The area and contrast ratio (CR) of the substantia nigra pars compacta (SNc) were comparatively analyzed.The total area and CR of the SNc upon follow-up NMI were significantly smaller than those on initial NMI (from 33.5±18.9 pixels and 6.35±2.86% to 21.5±16.7 pixels and 4.19±2.11%; Wilcoxon signed-rank test, p<0.001 and p=0.022, respectively). The area and CR of the dominant side SNc upon initial NMI were significantly greater than those on follow-up NMI (from 15.3±9.1 pixels and 6.5±2.7% to 7.9±8.5 pixels and 3.7±2.9%; Wilcoxon signed-rank test, p=0.002 and p=0.007, respectively). On a case-by-case basis, the area of the SNc invariably decreased upon follow-up NMI in all patients. We further demonstrated that the total area and CR of the SNc negatively correlated with disease duration (Pearson correlation coefficient, r=-0.63, p<0.001 and r=-0.41, p=0.031, respectively). In area analyses, our results demonstrated very high intraclass correlation coefficients for both intra- and inter-rater reliability.NMI is a useful and reliable tool for detecting neuropathological changes over time in PD patients.