Cerebral microbleeds linked to structural network disruption and cognitive impairment in white matter hyperintensities

Objective

This study aims to explore the relationship between the cerebral microbleeds (CMBs) and white matter structural network in patients with white matter hyperintensities (WMHs), and the correlation with the cognitive impairment.

Method

One hundred and fifty-eight participants with WMHs underwent 3.0 T magnetic resonance imaging scans and neuropsychological assessment. The grouping method included count grading with categories: non-CMBs (n-CMBs), CMBs < 5, and CMBs ≥ 5. Additionally, the distribution of CMBs was considered, distinguishing between strictly lobar CMBs (SL-CMBs) and deep or infratentorial CMBs (DI-CMBs). Diffusion tensor imaging was employed to construct the white matter structural network for each participant. Subsequently, we analyzed the correlations between the topological parameters of network and cognitive performance in individuals with CMBs.

Results

Compared with n-CMBs group, both CMBs ≥ 5 and DI-CMBs participants exhibited a significant decreased in global efficiency and increased in characteristic path length. Moreover, in the nodal network metrics, the CMBs ≥ 5 showed the left middle occipital gyrus (MOG.L) of nodal efficiency and nodal shortest path correlated with SCWT-A and MMSE, while in the DI-CMBs groups, the left cuneus (CUN.L) of nodal shortest path correlated with SCWT-A. However, there were no significant neuropsychological correlations observed in the SL-CMBs and CMBs < 5 groups.

Conclusion

In this study, patients with a high count (≥5) of CMBs or DI-CMBs are associated with disruptions in the microstructure of the white matter structural network, partially impacting the visual network of occipital lobe and affecting the cognitive function of information processing speed and attention.