Associations between cerebral SVD and inflammation have been largely examined using peripheral blood markers of inflammation, with few studies measuring inflammation within the brain. This study was done to investigate the between SVD and in vivo neuroinflammation using PET imaging.

42 participants were recruited which included 14 healthy controls, 14 mild Alzheimer’s disease, 14 amyloid-positive mild cognitive impairment. Neuroinflammation was assessed using [11C]PK11195 PET imaging, a marker of microglial activation. WMH, enlarged perivascular spaces, cerebral microbleeds and lacunes were assessed. Composite scores were calculated for global SVD burden, and SVD subtypes of hypertensive arteriopathy and CAA. General linear models examined associations between SVD and [11C]PK11195, adjusting for sex, age, education, cognition, scan interval, and corrected for multiple comparisons via false discovery rate (FDR). Dominance analysis directly compared the relative importance of hypertensive arteriopathy and CAA scores as predictors of [11C]PK11195.

Global [11C]PK11195 binding was associated with SVD markers, particularly in regions typical of hypertensive arteriopathy and in 28 out of 37 regions of interest, especially the medial temporal lobe (β=0.66–0.76, t=3.90–5.58, FDR-corrected p (pFDR)=<0.001–0.002) and orbitofrontal cortex (β=0.51–0.57, t=3.53–4.30, pFDR=0.001–0.004).

The study concluded that the microglial activation is associated with SVD, particularly with the hypertensive arteriopathy subtype of SVD.