Satoh, Ryota

AbstractBackground and purposePrimary lateral sclerosis (PLS) is a neurodegenerative disorder that primarily affects the central motor system. In rare cases, clinical features of PLS may overlap with those of progressive supranuclear palsy (PSP). We investigate neuroimaging features that can help distinguish PLS with overlapping features of PSP (PLS‐PSP) from PSP.MethodsSix patients with PLS‐PSP were enrolled between 2019 and 2023. We compared their clinical and neuroimaging characteristics with 18 PSP–Richardson syndrome (PSP‐RS) patients and 20 healthy controls. Magnetic resonance imaging, 18F‐flortaucipir positron emission tomography (PET), quantitative susceptibility mapping, and diffusion tensor imaging tractography (DTI) were performed to evaluate eight brain regions of interest. Area under the receiver operating characteristic curve (AUROC) was calculated.ResultsFive of the six PLS‐PSP patients (83.3%) were male. Median age at symptom onset was 61.5 (52.5–63) years, and all had mixed features of PLS and PSP. Volumes of the pallidum, caudate, midbrain, and cerebellar dentate were smaller in PSP‐RS than PLS‐PSP, providing good discrimination (AUROC = 0.75 for all). The susceptibilities in pallidum, midbrain, and cerebellar dentate were greater in PSP‐RS compared to PLS‐PSP, providing excellent discrimination (AUROC ≥ 0.90 for all). On DTI, fractional anisotropy (FA) in the posterior limb of the internal capsule from the corticospinal tract was lower in PLS‐PSP compared to PSP‐RS (AUROC = 0.86), but FA in the superior cerebellar peduncle was lower in PSP‐RS (AUROC = 0.95). Pallidum flortaucipir PET uptake was greater in PSP‐RS compared to PLS‐PSP (AUROC = 0.74).ConclusionsRegional brain volume, tractography, and magnetic susceptibility, but not tau‐PET, are useful in distinguishing PLS‐PSP from PSP.

AbstractBackgroundPrevious studies have shown that magnetic susceptibility is increased in several subcortical regions in progressive supranuclear palsy (PSP). However, it is still unclear how subcortical and cortical susceptibilities vary across different PSP variants, Parkinson's disease (PD), and corticobasal syndrome (CBS).ObjectiveThis study aims to clarify the susceptibility profiles in the subcortical and cortical regions in different PSP variants, PD, and CBS.MethodsSixty‐four patients, 20 PSP‐Richardson syndrome (PSP‐RS), 9 PSP‐parkinsonism (PSP‐P), 7 PSP‐progressive gait freezing, 4 PSP‐postural instability, 11 PD, and 13 CBS, and 20 cognitively normal control subjects underwent a 3‐Tesla magnetic resonance imaging scan to reconstruct quantitative susceptibility maps. Region‐of‐interest analysis was performed to obtain susceptibility in several subcortical and cortical regions. Bayesian linear mixed effect models were used to estimate susceptibility within group and differences between groups.ResultsIn the subcortical regions, patients with PSP‐RS and PSP‐P showed greater susceptibility than control subjects in the pallidum, substantia nigra, red nucleus, and cerebellar dentate (P < 0.05). Patients with PSP‐RS also showed greater susceptibility than patients with PSP‐progressive gait freezing, PD, and CBS in the red nucleus and cerebellar dentate, and patients with PSP‐P showed greater susceptibility than PD in the red nucleus. Patients with PSP‐postural instability and CBS showed greater susceptibility than control subjects in the pallidum and substantia nigra. No significant differences were observed in any cortical region.ConclusionsThe PSP variants and CBS had different patterns of magnetic susceptibility in the subcortical regions. The findings will contribute to our understanding about iron profiles and pathophysiology of PSP and may provide a potential biomarker to differentiate PSP variants, PD, and CBS. © 2023 International Parkinson and Movement Disorder Society.