Small vessel function & microinfarcts: zooming in on cerebral small vessel disease with MRI

Abstract

Cerebral small vessel disease (cSVD) refers to pathological processes that affect the small vessels in the brain. cSVD is a major cause of stroke and dementia. Despite these serious consequences, there is no specific treatment available, which has to do with the fact that underlying disease mechanisms are not entirely clear. The overarching aim of this thesis was to characterize new MRI markers that could help in better understanding disease mechanisms in cSVD. First, we wanted to study a marker that is close to the disease processes that occur in the cerebral small vessels. Because of the small diameter of the affected vessels, we were, for a long time, unable to study cSVD at the level of the small vessels themselves. With the development of stronger MRI scanners, this is now possible. We used such a strong scanner to zoom into the functioning of the small cerebral vessels and found that we could image abnormal small vessel function. These new measures allow to study cSVD at its core, reflecting a paradigm shift in the field. Second, we studied possible causes and consequences of a subtle marker of tissue injury in cSVD; cerebral microinfarcts. We found that microinfarcts are likely caused by cerebral amyloid angiopathy (a specific form of cSVD) and hypoperfusion. More importantly, we found that the presence of an acute microinfarct could predict long-term clinical outcome in patients with cSVD: cognitive decline, stroke, admission to a care facility and death, were more common in patients with an acute microinfarct.