[Relationship between small vessel disease load and cerebral blood flow and white matter integrity in patients with subcortical ischemic vascular dementia].

To evaluate markers of cerebral small vessel disease (SVD), cerebral blood flow (CBF), and white matter integrity in patients with subcortical ischemic vascular dementia (SIVD) using multimodal magnetic resonance imaging (MRI), and to analyze the impact of total SVD load on cerebral perfusion and white matter injury. Fifty SIVD patients who visited the Cognitive Disorders Clinic of Tianjin Medical University General Hospital between October 2017 and October 2022 were enrolled and underwent 3.0 T multimodal MRI examination. A total SVD load score was calculated based on the severity of white matter hyperintensities (WMH), lacunes, enlarged perivascular space (EPVS), and cerebral microbleeds (CMB). The patients were divided into a low total SVD load group (0-4 points, n=32) and a high total SVD load group (5-6 points, n=18). CBF and white matter integrity were assessed using arterial spin labeling (ASL) and diffusion tensor imaging (DTI), respectively. Independent-sample t-test and χ2 test were used for intergroup comparison. Binary logistic regression model was adopted to analyze the correlation of various imaging markers with CBF and DTI parameters in all subjects. Compared with the low total SVD load group, the high total SVD load group exhibited reduced CBF in the right cerebellar posterior lobe and tonsil [(45.7±14.9) vs (59.6±12.5) ml·(100 g)-1·min-1, t=3.52, P<0.01], left superior frontal gyrus [(22.2±6.3) vs (26.8±6.0) ml·(100 g)-1·min-1, t=2.55, P=0.01], left middle frontal gyrus [(50.6±15.8) vs (60.5±14.8) ml·(100 g)-1·min-1, t=2.22, P=0.03], and right middle frontal gyrus [(58.7±16.1) vs (67.7±12.7) ml·(100 g)-1·min-1, t=2.18, P=0.04]. Decreased fractional anisotropy values (all P<0.05) and increased mean diffusivity values (all P<0.05) were observed in multiple white matter regions, including the corpus callosum, right cerebral peduncle, bilateral internal capsules, bilateral anterior corona radiata, bilateral posterior corona radiata, bilateral posterior thalamic radiation, bilateral cingulate gyri, and bilateral frontoparietal superior fasciculi. Meanshile, reduced CBF and impaired white matter integrity in these brain regions were correlated with scores of individual SVD markers and the total SVD load score (all P<0.05). The total SVD load is closely associated with decreased cerebral perfusion and impaired white matter integrity in SIVD patients, which is an important pathological mechanism underlying brain dysfunction.