Cerebral Microbleeds Are Associated with Loss of White Matter Integrity

Abstract

BACKGROUND AND PURPOSE: Previous studies have shown that diffusion tensor imaging suggests a diffuse loss of white matter integrity in people with white matter hyperintensities or lacunes. The purpose of this study was to investigate whether the presence of cerebral microbleeds and their distribution are related to the integrity of white matter microstructures. MATERIALS AND METHODS: The study comprised 982 participants who underwent brain MR imaging to determine microbleed status. The cross-sectional relation between microbleeds and the microstructural integrity of the white matter was assessed by 2 statistical methods: a multilinear regression model based on the average DTI parameters of normal-appearing white matter and Tract-Based Spatial Statistics analysis, a tract-based voxelwise analysis. Fiber tractography was used to spatially describe the microstructural abnormalities along WM tracts containing a cerebral microbleed. RESULTS: The presence of cerebral microbleeds was associated with lower mean fractional anisotropy and higher mean diffusivity, axial diffusivity, and radial diffusivity, and the association remained when cardiovascular risk factors and cerebral small-vessel disease markers were further adjusted. Tract-Based Spatial Statistics analysis indicated strictly lobar cerebral microbleeds associated with lower fractional anisotropy, higher mean diffusivity, and higher radial diffusivity in the internal capsule and corpus callosum after adjusting other cerebral small-vessel disease markers, while only a few voxels remained associated with deep cerebral microbleeds. Diffusion abnormalities gradients along WM tracts containing a cerebral microbleed were not found in fiber tractography analysis. CONCLUSIONS: Cerebral microbleeds are associated with widely distributed changes in white matter, despite their focal appearance on SWI. ABBREVIATIONS: CMB ¼ cerebral microbleed; CSVD ¼ cerebral small vessel disease; MD ¼ mean diffusivity; FA ¼ fractional anisotropy; NAWM ¼ normalappearing white matter; WMH ¼ white matter hyperintensity; TBSS ¼ Tract-Based Spatial Statistics A ccording to recent evidence, cerebral small vessel disease (CSVD) was found to have focal brain parenchymal lesions not only visible on brain MR imaging but also related to a wider range of white matter microstructural injury. 1-3 These studies mainly focused on ischemic lesions related to CSVD, such as lacunes or white matter hyperintensities. Cerebral microbleeds (CMBs), characterized as focal hemosiderin deposits without remarkable brain tissue loss in

Disrupted topological organization of resting‐state functional brain networks in cerebral small vessel disease

“…In this research, CMBs were scored based on absence or presence, not number or location (Debette, Schilling, Duperron, Larsson, & Markus, 2019). Seven CSVD‐c patients belong to lobar CMBs group and 17 CSVD‐c patients are placed in deep CMBs group (Liu et al, 2020). WMHs were graded using Fazekas scale (0–3) and the number of lacunes was graded from 0 to 3 (0 = none, 1 = 1–2, 2 = 3–5, 3 =>5) (Fazekas, Chawluk, Alavi, Hurtig, & Zimmerman, 1987; Amin Al Olama et al, 2020).…”

Altered Spontaneous Brain Activity Related to Neurologic Dysfunction in Patients With Cerebral Small Vessel Disease

“…CMBs were scored on the basis of absence or presence, not location or quantity (Debette et al, 2019). In this study, 7 CSVD-c patients belong to lobar CMBs group and 17 CSVD-c patients belong to deep CMBs group (Liu et al, 2020). WMHs were graded using Fazekas scale (0-3) (Fazekas et al, 1987), and the number of lacunes was graded from 0 to 3 (0 = none, 1 = 1-2, 2 = 3-5, 3 = >5) (Amin Al Olama et al, 2020).…”

Contrast agent‐free state‐of‐the‐art magnetic resonance imaging on cerebral small vessel disease – Part 2: Diffusion tensor imaging and functional magnetic resonance imaging

“…A study protocol for the differential assessment of cSVD recommended quantitative DTI measurements of tissue integrity to assess WMH, less‐intense and severe WMH, stroke lesions, normal‐appearing WM (NAWM), deep gray matter (GM), and hippocampi 15 . In cSVD patients, DTI‐derived parameters, such as FA and MD, have been altered in WMH and NAWM, 16,17 were correlated with CMB, 18,19 and predicted dementia, risk of mortality, and cSVD severity 20–22 . Moreover, DTI abnormalities have been associated with cSVD genetic 23 and risk factors, such as hypertension, 24,25 increased salt intake, 26 aortic stiffness, 27 midlife systemic inflammation, 28 renal function, 29 and level of physical activity 30 .…”