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Updated: Oct 18, 2025
Standardized Data Acquisition for Neuromelanin-Sensitive Magnetic Resonance Imaging of the Substantia Nigra
Published on: September 8, 2021
Differential Effect of Iron and Myelin on Susceptibility MRI in the Substantia Nigra
Hansol Lee1, HyungJoon Cho1, Myung Jun Lee1
1From the Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea (H.L., H.J.C.); Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea (M.J.L); and Research Institute for Convergence of Biomedical Science and Technology (T.H.K.) and Departments of Radiology (J.R.) and Neurology (J.H.L.), Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, 20 Geumo-ro, Mulgeum-eup, Yangsan-si, Gyeongsangnam-do, South Korea.
Abstract:
Background The heterogeneous composition of substantia nigra (SN), including iron, nigrosome-1 substructure, and myelinated white matter, complicates the interpretation of MRI signals. Purpose To investigate R2* and quantitative susceptibility mapping (QSM) in the SN subdivisions of participants with Parkinson disease and healthy control subjects. Materials and Methods In this prospective study conducted from November 2018 to November 2019, participants with Parkinson disease and sex-matched healthy control subjects underwent 3-T MRI. R2* and QSM values were measured and compared in the anterior SN and posterior SN at the rostral (superior) and caudal (inferior) levels. Postmortem MRI and histology correlation of midbrain tissues was evaluated to investigate the effect of myelin and iron in the SN on R2* and QSM values. Results Forty individuals were evaluated: 20 healthy control subjects (mean age, 61 years ± 3 [standard deviation]; 10 men) and 20 participants with Parkinson disease (mean age, 61 years ± 4; 10 men). The R2* values of participants with Parkinson disease were higher in all subdivisions of the SN compared with R2* values in healthy control subjects (all P < .05). For QSM, no evidence of a difference was found in the rostral posterior SN (healthy control subjects, 54.1 ppb ± 21.0; Parkinson disease, 62.2 ppb ± 19.8; P = .49). The combination of rostral R2* and caudal QSM values resulted in an area under the receiver operating characteristic curve of 0.84. R2* values showed higher correlation with QSM values at the caudal level than at the rostral level within each group (all P < .001). Postmortem investigation demonstrated that R2* and QSM values showed weak correlation in the myelin-rich areas (r = 0.22 and r = 0.36, P < .001) and strong correlation in myelin-scanty areas (r ranged from approximately 0.52 to approximately 0.78, P < .001) in the SN. Conclusion Considering the iron and myelin distribution in the substantia nigra subdivisions, the subdivisional analysis of substantia nigra using R2* and quantitative susceptibility mapping might aid in specifically differentiating individuals with Parkinson disease from healthy control subjects. © RSNA, 2021 Online supplemental material is available for this article.
Insights
Magnetic resonance imaging (MRI) using R2* and quantitative susceptibility mapping (QSM) can help differentiate Parkinson disease patients from healthy individuals. Analyzing substantia nigra subdivisions with these MRI techniques shows promise for improved diagnostic accuracy.
Area of Science:
- Neuroimaging
- Radiology
- Neurology
Background:
- Substantia nigra (SN) composition (iron, nigrosome-1, myelin) complicates MRI signal interpretation.
- Parkinson disease (PD) diagnosis relies on identifying neurodegeneration in the SN.
Purpose of the Study:
- To investigate R2* and quantitative susceptibility mapping (QSM) in SN subdivisions for PD detection.
- To correlate MRI findings with postmortem histology for myelin and iron effects.
Main Methods:
- Prospective 3-T MRI study of 20 PD patients and 20 controls.
- Measured R2* and QSM in anterior/posterior SN at rostral/caudal levels.
- Postmortem MRI and histology correlation in midbrain tissues.
Main Results:
- Higher R2* values in all SN subdivisions for PD patients compared to controls (P < .05).
- No significant QSM difference in rostral posterior SN (P = .49).
- Combined rostral R2* and caudal QSM yielded AUC of 0.84.
- R2* and QSM correlation varied with myelin content in SN subdivisions.
Conclusions:
- Subdivisional analysis of SN using R2* and QSM may help differentiate PD patients from controls.
- MRI parameter sensitivity to iron and myelin distribution is key.
- Further research into advanced MRI techniques for PD diagnosis is warranted.
