Quantitative Susceptibility Mapping of Brain Iron Relating to Cognitive Impairment in Hypertension.

Background: Hypertension (HTN) might impair cognition. Brain iron deposition correlates with cognitive impairment. The relationship between brain iron and cognition in HTN patients is less clear.

Purpose: To measure brain susceptibility in HTN patients using quantitative susceptibility mapping (QSM) and to explore the relationship between brain iron and cognition.

Study Type: Retrospective cross-sectional study.

Subjects: Sixty HTN patients (35 with mild cognitive impairment [MCI] and 25 without MCI) and 24 age, gender, and education matched controls.

Field Strength/sequence: 3 T; strategically acquired gradient echo (STAGE) imaging protocol for QSM analysis.

Assessment: All subjects underwent Montreal Cognitive Assessment (MoCA) scoring of visuospatial/executive, naming, attention, abstraction, language, delayed memory, and orientation functions. HTN patients were divided into two groups (with and without MCI) depending on the MoCA score. Regions of interest (ROIs) were manually demarcated on the STAGE images by three independent radiologists and susceptibility were determined for bilateral frontal white matter, parietal white matter, occipital white matter, caudate nucleus (CN), putamen (PU), globus pallidus (GP), thalamus (TH), red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN).

Statistical Tests: Analysis of variance with post-hoc least significant difference (LSD) tests and Pearson correlation coefficients (r). A P-value <0.05 was considered to be statistically significant.

Results: The susceptibility was significantly different in CN, PU, and DN among the three groups. The susceptibility of right CN and left PU were correlated with MoCA scores (r = -0.429 and r = -0.389, respectively). The susceptibility of left PU was also correlated with delayed memory scores (r = -0.664). The susceptibility of left and right GP were correlated with naming scores (r = -0.494 and r = -0.446, respectively) and the susceptibility of left DN were correlated with visuospatial/executive scores (r = 0.479).

Data Conclusion: QSM measured brain iron was significantly higher in CN, PU, and DN in HTN patients. Cognitive impairment was correlated with regional brain iron deposition.

Level Of Evidence: 2 TECHNICAL EFFICACY: Stage 3.