Arjen Lindenholz

185 Summary 8 caused by small vessel disease and moderate to severe periventricular white matter hyperintensities. The results of these studies (I) tentatively support the notion that the detected vessel wall lesions most likely represent true atherosclerotic lesions rather than for example normal variations in vessel wall thickness; (II) suggest a risk factor profile for the development of intracranial vessel wall lesions comparable with that for extracranial atherosclerosis, which might be addressed with risk factor reduction; and (III) show the relation of these vessel wall lesions with damage to the cerebral parenchyma. Nonetheless, larger studies will be necessary to assess whether medical intervention (e.g., treatment with antihypertensive drugs) indeed changes lesion burden and/or cerebral damage. Finally, in Chapter 7 intracranial vessel wall MRI was used as non-invasive imaging technique to assess possible vessel wall damage after intra-arterial thrombectomy (IAT). Vessel wall enhancement was seen more frequently and in a concentric configuration on the ipsilateral side in patients treated by IAT than in patients who did not receive this treatment, suggesting reactive changes of the vessel wall after IAT which should be taken into consideration during follow-up MRI of the vessel wall. This thesis shows the potential value of intracranial vessel wall MRI in clinical practice; next steps in advancing clinical translation of intracranial vessel wall MRI are histopathological validation of detected vessel wall lesions, setup of larger studies to identify the exact association between vessel wall lesions, clinical characteristics and clinical outcome, and formation of international collaborative projects to standardize acquisition and assessment of vessel wall MR images. Ultimately, intracranial vessel wall MRI has the strong potential to be implemented in the workup and follow-up of patients with cerebrovascular disease, in risk management, and in diagnosing other vasculopathies, using it as non-invasive diagnostic tool to guide preventive and therapeutic decision-making.