IRONMAP: Iron Network Mapping and Analysis Protocol for Detecting Over-Time Brain Iron Abnormalities in Neurological Disease
Journal:
arXiv
Published Date:
Jan 29, 2025
Abstract
Pathologically altered iron levels, detected using iron-sensitive MRI
techniques such as quantitative susceptibility mapping (QSM), are observed in
neurological disorders such as multiple sclerosis (MS) and may play a crucial
role in disease pathophysiology. However, brain iron changes occur slowly, even
in neurological diseases, and can be influenced by physiological factors such
as diet. Therefore, novel analysis methods are needed to improve sensitivity to
disease-related iron changes as compared to conventional region-based analysis
methods. This study introduces IRONMAP, Iron Network Mapping and Analysis
Protocol, which is a novel network-based analysis method to evaluate over-time
changes in magnetic susceptibility. With this novel methodology, we analyzed
short-term (<1 year) longitudinal QSM data from a cohort of individuals with MS
(pwMS) and healthy controls (HCs) and assessed disease-related network
patterns, comparing the new approach to a conventional per-region
rate-of-change method. IRONMAP analysis was able to detect over-time,
MS-related brain iron abnormalities that were undetectable using the
rate-of-change approach. IRONMAP was applicable on the per-subject level,
improving binary classification of pwMS vs HCs compared to rate-of-change data
alone (areas under the curve: 0.773 vs 0.636, p = 0.024). Further analysis
revealed that the observed IRONMAP-derived HC network structure closely aligned
with simulated networks based on healthy aging-related susceptibility data,
suggesting that disruptions in normal aging-related iron changes may contribute
to the network differences seen in pwMS. IRONMAP is generalizable to any
neurological disease, including Alzheimer's disease and Parkinson's disease,
and may allow for study of brain iron abnormalities over shorter timeframes
than previously possible.
