Trujillo, Paula.; Hett, Kilian.; Cooper, Amy.; Brown, Amy E.; Donahue, Manus J.; McKnight, Colin D.; Bradbury, Margaret.; Wong, Cynthia.; Stamler, David.; Claassen, Daniel O. (2026).听.听NeuroImage, 334, 121965.听
Multiple system atrophy, or MSA, is a fast-moving brain disease that can be hard to diagnose early and monitor over time. This study looked at whether a special kind of MRI scan called quantitative susceptibility mapping, or QSM, can detect abnormal iron buildup in the brain, since iron imbalance may play a role in MSA and could be useful for tracking the disease. The researchers scanned 38 people with MSA, including 10 with early-stage disease who were followed again after 12 months, along with 43 people with Parkinson鈥檚 disease and 23 healthy adults of similar age. They measured iron-related changes in several brain regions, including the substantia nigra, globus pallidus, putamen, and dentate nucleus. Compared with both Parkinson鈥檚 disease and healthy controls, people with MSA had higher iron-related signal changes in the globus pallidus and substantia nigra, with smaller changes in the putamen. A more sensitive analysis that focused on higher values within each region detected these differences better than simple median measurements, suggesting it was better at picking up small, localized areas of iron buildup. Higher iron levels in the globus pallidus were also linked to worse clinical symptoms. In the 12-month follow-up, iron-related changes increased in the substantia nigra and globus pallidus, showing that these abnormalities can worsen over time. Overall, the findings suggest that QSM MRI may be a useful way to help diagnose MSA earlier, follow disease progression, and evaluate treatments aimed at reducing iron-related damage.
Fig. 1.听Representative QSM images from each diagnostic group.Quantitative susceptibility maps (QSM) for representative female participants matched for age across cohorts: a healthy control (HC, 67 years), Parkinson鈥檚 disease (PD, 62 years), PD from the bioMUSE study (69 years), multiple system atrophy (MSA) from bioMUSE (65 years), and MSA from the cross-sectional cohort (72 years). The PD (bioMUSE) participant was initially enrolled as MSA but later reclassified as PD based on longitudinal clinical evaluation. The MSA (bioMUSE) participant represents an early-stage case, whereas the MSA (cross-sectional) participant had more advanced disease. Each row displays a different subcortical region: the putamen (PT) and globus pallidus (GP) (top), the substantia nigra (SN) (middle), and the dentate nucleus (DN) (bottom). The leftmost column shows the QSM overlaid on the T1-weighted image to provide anatomical context. The second column shows the zoomed QSM for the HC participant with atlas-derived ROI outlines in red and anatomical labels. The remaining columns show the zoomed QSM for each diagnostic group. White arrows indicate the structures of interest in each row. Increases in magnetic susceptibility (brighter signal) are visible in the PT, GP, and SN in MSA participants compared with HC and PD. Susceptibility values are displayed in parts per million (ppm) using a grayscale colormap windowed from 鈭�0.1 to 0.2 ppm.