Medical University of Graz
Neurology

Author Of 1 Presentation

Imaging Poster Presentation

P1144 - Comparison of deep grey matter iron deposition assessed by 3T MRI R2* relaxometry in Multiple Sclerosis, Alzheimer´s disease and in normal controls (ID 1479)

Abstract

Background

Increased brain iron deposition has been described in different nosologic entities such as Multiple Sclerosis (MS) and Alzheimer’s disease (AD). However, it is still unclear whether abnormal brain iron accumulation contributes to the pathology of these diseases or merely reflects an epiphenomenon.

Objectives

To investigate deep grey matter iron deposition and its association with morphological brain changes and clinical data in patients with MS, AD and in normal controls (NC).

Methods

Participants with MS (n=196, mean age: 39±11 years), AD (n=116, mean age: 73±9 years) and NC (n=164, mean age: 66±11 years), underwent comprehensive clinical examination and brain MRI at 3T. Iron concentrations in deep grey areas (basal ganglia (BG), thalamus, hippocampus) were quantified by R2* relaxometry. Normalized brain volumes, T2 lesion load (LL) in MS and White Matter Hyperintensity (WMH) volumes in AD and NC were determined on T2-FLAIR and T1-weighted sequences, respectively.

Results

R2* relaxation rates increased with age in the BG. This relationship was strongest in MS (r=0.63, p<0.001), followed by AD (r=0.25, p=0.005) and NC (r=0.25, p=0.001). Higher BG R2* relaxation rates were associated with lower brain volumes, particularly concerning grey matter in MS (r= -0.51, p<0.001) and NC (r= -0.23, p=0.002) but not in AD. BG R2* relaxation rates correlated to T2 LL (r=0.45, p<0.001) in MS, but were unrelated to WMH volume in AD and NC. In MS, BG R2* relaxation rates further correlated with higher EDSS scores (r=0.28, p<0.001) and increased disease duration (r=0.35, p<0.001). Multivariate linear regression analysis revealed, that in MS age (beta=0.53, p<0.001) and T2 LL (beta=0.33, p<0.001) independently predicted BG R2* relaxation rates. In contrast, age was the only variable independently predicting BG R2* relaxation rates in AD (beta=0.26, p=0.011) and NC (beta= 0.32, p=0.026).

Conclusions

This comparative study confirms that age is a main driving factor for deep grey matter iron accumulation in MS, AD and NC. However, only in MS we found evidence for increased BG iron deposition to be associated with morphologic brain changes, supporting the notion that a dysbalanced iron homeostasis is involved in MS pathology. Further analyses on longitudinal MRI and clinical data are currently ongoing to confirm and extent our findings.

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