A Comparison of Substantia Nigra T1 Hyperintensity in Parkinson's Disease Dementia, Alzheimer's Disease and Age-Matched Controls: Volumetric Analysis of Neuromelanin Imaging

Abstract

ObjectiveNeuromelanin loss of substantia nigra (SN) can be visualized as a T1 signal reduction on T1-weighted high-resolution imaging. We investigated whether volumetric analysis of T1 hyperintensity for SN could be used to differentiate between Parkinson's disease dementia (PDD), Alzheimer's disease (AD) and age-matched controls.Materials and MethodsThis retrospective study enrolled 10 patients with PDD, 18 patients with AD, and 13 age-matched healthy elderly controls. MR imaging was performed at 3 tesla. To measure the T1 hyperintense area of SN, we obtained an axial thin section high-resolution T1-weighted fast spin echo sequence. The volumes of interest for the T1 hyperintense SN were drawn onto heavily T1-weighted FSE sequences through midbrain level, using the MIPAV software. The measurement differences were tested using the Kruskal-Wallis test followed by a post hoc comparison.ResultsA comparison of the three groups showed significant differences in terms of volume of T1 hyperintensity (p < 0.001, Bonferroni corrected). The volume of T1 hyperintensity was significantly lower in PDD than in AD and normal controls (p < 0.005, Bonferroni corrected). However, the volume of T1 hyperintensity was not different between AD and normal controls (p = 0.136, Bonferroni corrected).ConclusionThe volumetric measurement of the T1 hyperintensity of SN can be an imaging marker for evaluating neuromelanin loss in neurodegenerative diseases and a differential in PDD and AD cases.

Neuromelanin detection by magnetic resonance imaging (MRI) and its promise as a biomarker for Parkinson’s disease

“…Existing data from large cross-sectional studies show that the average NM-MRI signal in the entire SN increases with age in healthy individuals, 115 , 116 although this was not observed in some small studies. 90 , 97 , 117 , 118 Factors underlying this discrepancy could include subregional variability in age-related changes in the SNc NM-MRI signal (requiring detection by anatomically precise methods) or non-linearity in age-related changes if the signal declines in some fraction of individuals with advanced age. Indeed, both of these observations have been reported in investigations of age-related changes of the LC using NM-MRI.…”

Structural MR Imaging in the Diagnosis of Alzheimer's Disease and Other Neurodegenerative Dementia: Current Imaging Approach and Future Perspectives

“…Magnetic transfer (MT) imaging is based on the exchange of magnetization between free protons and protons bound to macromolecules, and reflects underlying histopathological changes in advance than does conventional MRI (142143). Reduced MTR values in the hippocampus have been observed independent of atrophy in even patients with very mild AD (144), thus supporting the contention that MT imaging can detect histopathological changes preceding to obvious volumetric changes in AD.…”

Multielement concentration analysis of Swiss mice brains on experimental model of Alzheimer's disease induced by β‐amyloid oligomers

“…More than a third of AD patients show akinesia (inability to initiate movement) and bradykinesia (slowness of movement). High prevalence of this dysfunction in AD patients suggests that the AD is a significant risk factor for the substantia nigra . In the normal adult brain, substantia nigra contains the highest Fe concentration, which explains why, in neurodegeneration movement disorders, this region is vulnerable to Fe imbalance .…”