Quantitative iron-neuromelanin MRI associates with motor severity in Parkinson's disease and matches radiological disease classification

• Published in: Frontiers in aging neuroscience Vol. 15; p. 1287917
• Main Authors: Hartono, Septian, Chen, Robert Chun, Welton, Thomas, Tan, An Sen, Lee, Weiling, Teh, Peik Yen, Chen, Celeste, Hou, Wenlu, Tham, Wei Ping, Lim, Ee Wei, Prakash, Kumar M, Shih, Yao-Chia, Lee, Kuan Jin, Tan, Louis C S, Tan, Eng King, Chan, Ling Ling
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 27-11-2023; Frontiers Media S.A
• Subjects: Aging Neuroscience; Biomarkers; Brain mapping; Classification; comparative study; correlation analysis; Iron; Magnetic resonance imaging; Medical screening; Mesencephalon; Movement disorders; MRI; Neurodegeneration; Neurodegenerative diseases; Neuroprotection; Parkinson's disease; Quantitative analysis; Statistical analysis; Substantia nigra; Susceptibility; Germany; correlation analysis; comparative study; substantia nigra; Parkinson's disease; MRI; neuromelanin; iron; classification
• ISSN: 1663-4365; 1663-4365
• DOI: 10.3389/fnagi.2023.1287917

Neuromelanin- and iron-sensitive MRI studies in Parkinson's disease (PD) are limited by small sample sizes and lack detailed clinical correlation. In a large case-control PD cohort, we evaluated the diagnostic accuracy of quantitative iron-neuromelanin MRI parameters from the substantia nigra (SN), their radiological utility, and clinical association.
PD patients and age-matched controls were prospectively recruited for motor assessment and midbrain neuromelanin- and iron-sensitive [quantitative susceptibility mapping (QSM) and susceptibility map-weighted imaging (SMWI)] MRI. Quantitative neuromelanin-iron parameters from the SN were assessed for their discriminatory performance in PD classification using ROC analysis compared to those of qualitative visual classification by radiological readers of differential experience and used to predict motor severity.
In total, 191 subjects (80 PD, mean age 65.0 years; 111 controls, 65.6) were included. SN masks showed (a) higher mean susceptibility (
< 0.0001) and smaller sizes after thresholding for low susceptibility (
< 0.0001) on QSM and (b) lower contrast range (
< 0.0001) and smaller sizes after thresholding for high-signal voxels (
< 0.0001) on neuromelanin-sensitive MRI in patients than in controls. Quantitative iron and neuromelanin parameters showed a moderate correlation with motor dysfunction (87.5%: 0.4< | r | <0.6,
< 0.0001), respectively. A composite quantitative neuromelanin-iron marker differentiated the groups with excellent performance (AUC 0.94), matching the diagnostic accuracy of the best-performing reader (accuracy 97%) using SMWI.
Quantitative neuromelanin-iron MRI is associated with PD motor severity and matched best-performing radiological PD classification using SMWI, with the potential to improve diagnostic confidence in the clinics and track disease progression and response to neuroprotective therapies.