Quantification of Iron Deposition in the Brain of Hypertensive Patients using 3D-enhanced Susceptibility-weighted Angiography (ESWAN)

Background: Cerebral microbleeds (CMBs) are commonly present in patients with hypertension, producing iron-containing metabolites. A small amount of regional iron deposition is hardly discernible on conventional magnetic resonance imaging (MRI). Three-dimensional enhanced susceptibility-weighted angiography (ESWAN) provides tissue images with high spatial resolution and signal-noise ratio, and has been widely used to measure brain iron deposition in neurodegenerative diseases and intracranial hemorrhage. Objective: The study aimed to demonstrate iron deposition in the brain of hypertensive patients using ESWAN. Methods: Twenty-seven hypertension patients, with or without CMBs, and 16 matched healthy controls (HCs) were enrolled. From the post-processed ESWAN images, phase and magnitude values of the regions of interest (ROIs) were calculated. Two-sample t-test and one-way variance analysis were applied to compare groups. The relationship between ESWAN parameters and clinical variables was assessed using Pearson's correlation coefficient. Results: Compared to HCs, the phase value of the hippocampus, head of caudate nucleus (HCN), and substantia nigra (SN) was decreased in hypertension with the CMBs subgroup, while that of HCN and SN was decreased in hypertension without CMBs subgroup. Similarly, the magnitude value of the hippocampus, HCN, thalamus red nucleus, and SN was significantly lower in the hypertension group than HCs. In addition, the phase and magnitude values showed a correlation with clinical variables, including disease duration and blood pressure. Conclusion: Deep grey matter nuclei displayed greater iron content in hypertension patients. Iron deposition may precede the appearance of CMBs on MRI, serving as a potential marker of microvascular damage.