Interest in the small vessels’ pathology is growing because of its contribution to cognitive impairment (Pantoni et al., 2009) and its possible interaction with AD-related pathology (Boyle et al., 2018). CSVD affects vessels (small arteries and veins, arterioles and capillaries), including the perforating arteries of the basal ganglia. Because of their small dimension, in vivo analysis of blood flow in these arteries is challenging. We applied an innovative 2D-Flow sequence at 7 Tesla MRI (Bouvy et al., 2016) in order to assess the blood flow velocity and pulsatility index (PI) of these arteries in 20 CSVD patients (mean [SD] age 71 [9] years, 65% male) and 28 healthy elderly controls (70 [9] years, 62% male). Vascular risk factors were also available in this cohort. Furthermore, we obtained MRI measures of 8 participants approximately a year from baseline. Using a MATLAB-based tool, we calculated the individual and average blood flow velocity curve and the PI value. We hypothesized to observe a relation between these measures, age and vascular risk factors, as well as a difference between healthy controls and CSVD and when comparing CSVD  subtypes, i.e. hypertensive arteriopathy and cerebral amyloid angiopathy. 
A positive correlation between age and PI ( r = 0.57, p < 0.001)  was demonstrated, irrespective of presence of CSVD ( healthy controls: r = 0.52, p = 0.007;  CSVD: r = 0.71, p 0 0.001). As opposed to a previous study (Geurts et al., 2018), we observed no difference in PI values and blood velocity neither between CSVD and controls, nor within CSVD subgroups. Furthermore, the analysis of longitudinal measures did not show significant changes over one year time. 
Our results suggest that age might be a main factor influencing small vessels’ stiffness, as it has already been shown in larger vessels, such as the medial cerebral artery (Zarrinkoob et al., 2016). We possibly failed to observe differences between groups because not all CSVD subjects in our cohort were severely affected by the disease, when compared to previous studies (Geurts et al., 2018).

REPRESENTATION OF BLOOD FLOW IN PERFORATING BASAL GANGLIA ARTERIES OF PATIENTS WITH CEREBRAL SMALL VESSEL DISEASE (CSVD) AT 7 TESLA MRI.