Magnetic resonance imaging markers of cerebral small vessel disease in an elderly population – association with cardiovascular disease and cognitive function

Abstract: Cerebral small vessel disease (SVD) is identifiable by clinical, neuroimaging, neuropathological and cognitive findings.The aim of this thesis was to assess SVD and cerebral perfusion on magnetic resonance imaging (MRI) in a 75-year-old population and compare the findings with scars of myocardial infarctions, cardiovascular risk markers and cognitive function. In addition, the evolution of SVD over 5 years was studied.The study population included subjects from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. The subjects had been chosen in a randomized manner from the register of the municipality. MRI of the brain and the heart, cognitive tests and blood tests for cardiovascular risk factors were performed in 406 subjects at age 75 years and 250 of them were re-examined 5 years later at the age of 80.Paper 1 showed that unrecognized myocardial infarctions (UMIs) were found in 120 subjects (30%) and recognized myocardial infarctions (RMIs) in 21 (5%). Men with RMIs displayed an increased prevalence of cortical and lacunar cerebral infarctions, whereas women with UMIs more frequently had cortical cerebral infarctions.Paper 2 showed that one or more brain infarcts were seen in 23% of the subjects (20% had only lacunar infarcts, 1% had only cortical infarcts and 2% had both). Hypertension and obesity were significantly associated with an increased risk of infarction.  The newer risk markers investigated were not significantly associated with brain infarcts.Paper 3 showed that MRI manifestations of SVD progressed over 5 years. Relative cerebral blood flow (rCBF) was not associated with WMH volume or progression of WMH volume.Paper 4 showed that moderate to severe WMHs and incident lacunar infarcts on brain MRI were associated with a mild impairment of executive function.In conclusion, this longitudinal population based study compares MRI manifestations of SVD with clinical data, providing knowledge that may be used in further investigations of preventive interventions and for identification of disease in early stages.