Quantitative susceptibility mapping of brain iron deposition in patients with type 2 diabetes mellitus

Background Noninvasive quantitative susceptibility mapping (QSM) analysis was applied to assess brain iron deposition in the gray matter nucleus in type 2 diabetes mellitus (T2DM) patients and healthy elderly individuals.Methods Thirty-two T2DM patients and thirty-two age- and gender-matched healthy controls (HCs) were enrolled in this research. All participants underwent brain magnetic resonance examinations. Twenty-three DM patients and twenty-six healthy controls received cognitive function assessments. Imaging data were collected with three-dimensional fast low-angle shot sequences to obtain magnitude and phase images; with preprocessed QSM data, ITK-SNAP helped to measure the susceptibility values reflecting the content of iron in the regions of interest (ROIs).Results The study included thirty-two T2DM patients (20 males and 12 females; mean age of 61.09 ± 9.99 years) and 32 HCs (14 males and 18 females; mean age of 59.09 ± 9.77 years). These participants were age- and gender-matched, with no significant difference ( P > 0.05). T2DM patients exhibited an obviously (P < 0.05) lower MoCA score (26.78 ± 2.35; normal standard, ≥ 27) and higher SCWT score (157 (128,188); HC, 123 (112,152)) than HCs. The mean susceptibility values in the left putamen and right putamen as well as dentate nucleus in the left thalamus appeared obviously higher in T2DM patients than in HCs (P < 0.05). In all participants, the susceptibility values in the left dentate nucleus were significantly higher than those in the right side ( P < 0.05). The susceptibility values and cognitive assessment scores showed no obvious association ( P > 0.05). However, an obvious correlation exists between the changes in the susceptibility values across hemispheres in the dentate nucleus and the putamen (left, r = 0.439, P = 0.000; right, r = 0.260, P = 0.038).Conclusion T2DM patients showed increased iron deposition in the putamen, dentate nucleus and left thalamus. Cerebral iron deposition exacerbates cognitive decline in T2DM patients. Changes in susceptibility values in these regions are likely to be quantitative imaging markers of central nervous system injury in T2DM patients, and QSM may benefit their detection and evaluation.