Voxel-Wise Whole-Brain Analysis in Quantitative Susceptibility Mapping: A Narrative Review

Quantitative susceptibility mapping (QSM) is a post-processing magnetic resonance imaging technique that quantifies the magnetic susceptibility of biological tissue and provides insights into factors such as iron deposition, hemorrhage, calcification, myelin content, and oxygen extraction fraction. A variety of analytical approaches have been developed to interpret QSM data from different perspectives, including region-of-interest-based, depth-wise, surface-based, network-based, and voxel-wise methods. Among these, voxel-wise analysis has gained increasing prominence due to its ability to perform a detailed examination of the entire brain without anatomically predefined regions. This approach is especially valuable for investigating neurological pathologies and aging-related changes, including neurodegenerative and neuropsychiatric disorders. This article aims to comprehensively summarize voxel-wise analysis in QSM by outlining key methodological considerations and clinical applications. Moreover, it offers practical data processing recommendations to advance the reproducibility and transparency of voxel-wise QSM research.