MRI T2 and T2* relaxometry to visualize neuromelanin in the dorsal substantia nigra pars compacta
Autor: | Hansol Lee, Gi Yeong Huh, HyungJoon Cho, Jae-Hyeok Lee, Eun-Joo Kim, Sun-Yong Baek |
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Rok vydání: | 2020 |
Předmět: |
Pathology
medicine.medical_specialty Relaxometry Parkinson's disease Cognitive Neuroscience Substantia nigra Neuromelanin 050105 experimental psychology lcsh:RC321-571 03 medical and health sciences 0302 clinical medicine Dopamine Depigmentation medicine 0501 psychology and cognitive sciences lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry medicine.diagnostic_test Chemistry Pars compacta Parkinsonism 05 social sciences Magnetic resonance imaging Transverse magnetic resonance relaxometries medicine.disease nervous system Neurology Parkinson’s disease 030217 neurology & neurosurgery medicine.drug |
Zdroj: | NeuroImage, Vol 211, Iss, Pp 116625-(2020) |
ISSN: | 1053-8119 |
DOI: | 10.1016/j.neuroimage.2020.116625 |
Popis: | 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. |
Databáze: | OpenAIRE |
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