Thesis defense Kim Wiegertjes (Donders series 517)

16 September 2021

Promotors: prof. dr. F.E. de Leeuw, prof. dr. K. Klijn
Copromotors: dr. A. Tuladhar,  dr. F. Schreuder

Ischemic and hemorrhagic MRI markers of cerebral small vessel disease, Two sides of the same coin?

Cerebral small vessel disease (SVD) is the major vascular contributor to cognitive impairment and dementia, and is the cause of a fifth of all strokes worldwide. Most often, SVD is due to aging and cardiovascular risk factors, and includes all pathological changes to the smallest cerebral blood vessels. These changes can lead to both ischemic and hemorrhagic markers of SVD, including WMH, lacunes, and microbleeds on conventional MRI. However, the MRI markers of SVD are heterogeneous and not completely understood, since animal models that are able to accurately capture the pathological changes in human SVD are limited. Furthermore, the reason why some vessels rupture while others occlude leading to (micro)infarction is poorly understood. Therefore, we aimed to provide a deeper understanding of the ischemic and hemorrhagic MRI markers of SVD.

We demonstrated that small, hyperintense lesions on diffusion-weighted imaging (DWI lesions), suggestive of acute infarcts, develop into MRI markers of SVD. The contribution of DWI lesions to WMH is minor, whereas DWI lesions explain most new lacunes and one-third of new microbleeds. Furthermore, we demonstrated that the presence of one or more DWI lesion in survivors of acute intracerebral hemorrhage (ICH) is associated with recurrent ICH, but not with ischemic stroke, providing a new perspective on the significance of DWI lesions, which may be markers of microvascular occlusive events that are associated with recurrent ICH. Together, our data demonstrate that although MRI markers of SVD can look heterogeneous on MRI, they may partly have a common origin.