Brain parenchymal changes on magnetic resonance imaging in cerebrovascular diseases

Cerebrovascular disease refers to a wide variety of conditions that lead to pathological changes in the blood vessels of the brain. These blood vessel changes can result in brain abnormalities. Although the clinical application of magnetic resonance imaging has substantially increased the knowledge on cerebrovascular diseases and their impact on the brain, there is a lack of knowledge with respect to several brain abnormalities that include white matter hyperintensities of vascular origin, microinfarcts in the deep gray matter and brain atrophy.

This thesis examines the detection, risk factors and relation to clinical outcomes of white matter hyperintensities (WMH) of vascular origin, microinfarcts in the deep gray matter and brain atrophy. Data was used from the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) study, a prospective cohort study at the University Medical Center Utrecht with the aim to investigate risk factors and consequences of brain changes on MRI in patients with symptomatic atherosclerotic disease.

In the first part, we examine advanced quantitative features of WMH on MRI and their relation to clinical outcomes. After developing an algorithm to extract information on quantitative features of WMH from brain MRI scans, we showed that a greater volume and a more irregular shape of WMH were related to an increased risk of mortality and ischemic stroke.

In the second part, we focus on the detection, risk factors and relation to cognitive functioning of microinfarcts in the deep gray matter on ultra-high field 7 tesla MRI. We observed that these lesions could be reliably detected on 7 tesla MRI, were associated with markers of both large vessel and small vessel disease, and were related to poorer cognitive functioning.

In the last part, we examined potential risk factors for increased brain atrophy. We found that a reduced cerebral blood flow (measured on brain MRI) and mild carotid atherosclerosis on ultrasound pose risk factors for increased brain atrophy.

The findings of this thesis may potentially be used in the future to identify patients who are at an increased risk for ischemic stroke, mortality and brain atrophy based on their brain MRI scan.