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MRI T2 and T2* relaxometry to visualize neuromelanin in the dorsal substantia nigra pars compacta.
Neuroimage. 2020 05 01; 211:116625.N

Abstract

Visualizing gradual changes in neuromelanin distribution within the substantia nigra is an important metric used to monitor the progression of Parkinsonism. This study aimed to identify the origin of the mismatch region between magnetic resonance transverse relaxation times (T2 and T2*) in the substantia nigra and investigate its feasibility and implications for in vivo detection of neuromelanin as a clinical biomarker. The relationships between neuromelanin distribution assessed by histological staining and the area of T2 and T2* mismatch determined by high- and low-resolution magnetic resonance relaxometry at 7T were directly compared in two normal and one depigmented substantia nigra collected at postmortem. In vivo feasibility of assessing T2 and T2* mismatch, clinically, was investigated using 3T magnetic resonance imaging. In the normal postmortem substantia nigra tissue, the T2 and T2* mismatch region exhibiting a linear pattern was strongly colocalized with neuromelanin distribution along the dorsal substantia nigra pars compacta, but a negligible amount of dorsal mismatch was observed in the depigmented brain. The regions of T2 and T2* mismatch from MRI, neuromelanin pigments from histology, and elevated iron signals from mass spectrometry were spatially overlapped for a normal postmortem brain. In preliminary in vivo studies, a similar, linear T2 and T2* mismatch region was observed in the dorsal area of the substantia nigra in eight normal subjects; this mismatch was significantly obscured in eight Parkinson's disease patients. The length of the dorsal linear mismatch line based on the T2*-T2 mask was significantly shorter in the Parkinson's disease patients compared to normal controls; this result was corroborated by reduced striatal uptake of [18F] FP-CIT dopamine transporters assessed by positron emission tomography scans. In conclusion, the measurement of T2 and T2* mismatch could serve as a complementary imaging biomarker to visualize the dorsal region of the substantia nigra pars compacta, which contains large amounts of neuromelanin.

Authors+Show Affiliations

Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea.Department of Anatomy, Pusan National University School of Medicine, Yangsan, South Korea.Department of Neurology, Pusan National University Hospital, Busan, South Korea.Department of Forensic Medicine, Pusan National University School of Medicine, Yangsan, South Korea.Department of Neurology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea. Electronic address: jhlee.neuro@pusan.ac.kr.Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea. Electronic address: hjcho@unist.ac.kr.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32058001

Citation

Lee, Hansol, et al. "MRI T2 and T2* Relaxometry to Visualize Neuromelanin in the Dorsal Substantia Nigra Pars Compacta." NeuroImage, vol. 211, 2020, p. 116625.
Lee H, Baek SY, Kim EJ, et al. MRI T2 and T2* relaxometry to visualize neuromelanin in the dorsal substantia nigra pars compacta. Neuroimage. 2020;211:116625.
Lee, H., Baek, S. Y., Kim, E. J., Huh, G. Y., Lee, J. H., & Cho, H. (2020). MRI T2 and T2* relaxometry to visualize neuromelanin in the dorsal substantia nigra pars compacta. NeuroImage, 211, 116625. https://doi.org/10.1016/j.neuroimage.2020.116625
Lee H, et al. MRI T2 and T2* Relaxometry to Visualize Neuromelanin in the Dorsal Substantia Nigra Pars Compacta. Neuroimage. 2020 05 1;211:116625. PubMed PMID: 32058001.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - MRI T2 and T2* relaxometry to visualize neuromelanin in the dorsal substantia nigra pars compacta. AU - Lee,Hansol, AU - Baek,Sun-Yong, AU - Kim,Eun-Joo, AU - Huh,Gi Yeong, AU - Lee,Jae-Hyeok, AU - Cho,HyungJoon, Y1 - 2020/02/11/ PY - 2019/11/05/received PY - 2020/02/05/revised PY - 2020/02/06/accepted PY - 2020/2/15/pubmed PY - 2021/2/23/medline PY - 2020/2/15/entrez KW - Depigmentation KW - Neuromelanin KW - Parkinson’s disease KW - Substantia nigra KW - Transverse magnetic resonance relaxometries SP - 116625 EP - 116625 JF - NeuroImage JO - Neuroimage VL - 211 N2 - Visualizing gradual changes in neuromelanin distribution within the substantia nigra is an important metric used to monitor the progression of Parkinsonism. This study aimed to identify the origin of the mismatch region between magnetic resonance transverse relaxation times (T2 and T2*) in the substantia nigra and investigate its feasibility and implications for in vivo detection of neuromelanin as a clinical biomarker. The relationships between neuromelanin distribution assessed by histological staining and the area of T2 and T2* mismatch determined by high- and low-resolution magnetic resonance relaxometry at 7T were directly compared in two normal and one depigmented substantia nigra collected at postmortem. In vivo feasibility of assessing T2 and T2* mismatch, clinically, was investigated using 3T magnetic resonance imaging. In the normal postmortem substantia nigra tissue, the T2 and T2* mismatch region exhibiting a linear pattern was strongly colocalized with neuromelanin distribution along the dorsal substantia nigra pars compacta, but a negligible amount of dorsal mismatch was observed in the depigmented brain. The regions of T2 and T2* mismatch from MRI, neuromelanin pigments from histology, and elevated iron signals from mass spectrometry were spatially overlapped for a normal postmortem brain. In preliminary in vivo studies, a similar, linear T2 and T2* mismatch region was observed in the dorsal area of the substantia nigra in eight normal subjects; this mismatch was significantly obscured in eight Parkinson's disease patients. The length of the dorsal linear mismatch line based on the T2*-T2 mask was significantly shorter in the Parkinson's disease patients compared to normal controls; this result was corroborated by reduced striatal uptake of [18F] FP-CIT dopamine transporters assessed by positron emission tomography scans. In conclusion, the measurement of T2 and T2* mismatch could serve as a complementary imaging biomarker to visualize the dorsal region of the substantia nigra pars compacta, which contains large amounts of neuromelanin. SN - 1095-9572 UR - https://www.unboundmedicine.com/medline/citation/32058001/MRI_T2_and_T2__relaxometry_to_visualize_neuromelanin_in_the_dorsal_substantia_nigra_pars_compacta_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1053-8119(20)30112-9 DB - PRIME DP - Unbound Medicine ER -