Cerebral hypoperfusion is associated with accelerated cognitive decline and an increased risk of dementia in the general population.

No abstract

Purpose To present an updated prevalence estimate for incidental findings on brain magnetic resonance (MR) images and provide information on clinical relevance, including natural course, over a period of up to 9 years. Materials and Methods This study was approved by the institutional review board and all participants gave informed consent. In a prospective population-based setting, structural brain MR imaging was performed in 5800 participants (mean age, 64.9 years; 3194 women [55.1%]). Trained reviewers recorded abnormalities, which were subsequently evaluated by neuroradiologists. The prevalence with 95% confidence interval (CI) of incidental findings was determined, and clinical management of findings that required the attention of a medical specialist was followed. Follow-up imaging in the study context provided information on the natural course of findings that were not referred. Results In 549 of 5800 participants (9.5% [95% CI: 8.7%, 10.3%]), incidental findings were found, of which meningiomas (143 of 5800; 2.5% [95% CI: 2.1%, 2.9%]) and cerebral aneurysms (134 of 5800; 2.3% [95% CI: 2.0%, 2.7%]) were most common. A total of 188 participants were referred to medical specialists for incidental findings (3.2% [95% CI: 2.8%, 3.7%]). Of these, 144 (76.6% [95% CI: 70.1%, 82.1%]) either underwent a wait-and-see policy or were discharged after the initial clinical visit. The majority of meningiomas and virtually all aneurysms not referred or referred but untreated remained stable in size during follow-up. Conclusion Incidental findings at brain MR imaging that necessitate further diagnostic evaluation occur in over 3% of the general middle-aged and elderly population, but are mostly without direct clinical consequences. RSNA, 2016.

ObjectiveTo determine the long-term association of hemoglobin levels and anemia with risk of dementia, and explore underlying substrates on brain MRI in the general population.MethodsSerum hemoglobin was measured in 12,305 participants without dementia of the population-based Rotterdam Study (mean age 64.6 years, 57.7% women). We determined risk of dementia and Alzheimer disease (AD) (until 2016) in relation to hemoglobin and anemia. Among 5,267 participants without dementia with brain MRI, we assessed hemoglobin in relation to vascular brain disease, structural connectivity, and global cerebral perfusion.ResultsDuring a mean follow-up of 12.1 years, 1,520 individuals developed dementia, 1,194 of whom had AD. We observed a U-shaped association between hemoglobin levels and dementia (p = 0.005), such that both low and high hemoglobin levels were associated with increased dementia risk (hazard ratio [95% confidence interval (CI)], lowest vs middle quintile 1.29 [1.09–1.52]; highest vs middle quintile 1.20 [1.00–1.44]). Overall prevalence of anemia was 6.1%, and anemia was associated with a 34% increased risk of dementia (95% CI 11%–62%) and 41% (15%–74%) for AD. Among individuals without dementia with brain MRI, similar U-shaped associations were seen of hemoglobin with white matter hyperintensity volume (p = 0.03), and structural connectivity (for mean diffusivity, p < 0.0001), but not with presence of cortical and lacunar infarcts. Cerebral microbleeds were more common with anemia. Hemoglobin levels inversely correlated to cerebral perfusion (p < 0.0001).ConclusionLow and high levels of hemoglobin are associated with an increased risk of dementia, including AD, which may relate to differences in white matter integrity and cerebral perfusion.

The prevalence of cortical SS in a memory clinic setting is higher than reported in the general population but lower than reported in cerebral amyloid angiopathy. The relatively high prevalence of SS in AD suggests that SS is a relevant radiologic manifestation of amyloid pathology in AD. Presence of SS does not seem to predict severity of AD. Further longitudinal research is needed to investigate clinical relevance.

No abstract

The question remains whether reduced cerebral blood flow (CBF) leads to brain atrophy or vice versa. We studied the longitudinal relation between CBF and brain volume in a community-dwelling population. In the Rotterdam Study, 3011 participants (mean age 59.6 years (s.d. 8.0)) underwent repeat brain magnetic resonance imaging to quantify brain volume and CBF at two time points. Adjusted linear regression models were used to investigate the bidirectional relation between CBF and brain volume. We found that smaller brain volume at baseline was associated with a steeper decrease in CBF in the whole population (standardized change per s.d. increase of total brain volume (TBV) = 0.296 (95% confidence interval (CI) 0.200; 0.393)). Only in persons aged ⩾ 65 years, a lower CBF at baseline was associated with steeper decline of TBV (standardized change per s.d. increase of CBF = 0.003 (95% CI − 0.004; 0.010) in the whole population and 0.020 (95% CI 0.004; 0.036) in those aged ⩾ 65 years of age). Our results indicate that brain atrophy causes CBF to decrease over time, rather than vice versa. Only in persons aged 465 years of age did we find lower CBF to also relate to brain atrophy.

ObjectiveTo assess potential mechanisms of cortical superficial siderosis (cSS), a central MRI biomarker in cerebral amyloid angiopathy (CAA), we performed a collaborative meta-analysis of APOE associations with cSS presence and severity.MethodsWe pooled data from published studies reporting APOE genotype and MRI assessment of cSS in 3 distinct settings: (1) stroke clinic patients with symptomatic CAA (i.e., lobar intracerebral hemorrhage, transient focal neurologic episodes) according to the Boston criteria; (2) memory clinic patients; and (3) population-based studies. We compared cSS presence and severity (focal or disseminated vs no cSS) in participants with ε2+ or ε4+ genotype vs the ε3/ε3 genotype, by calculating study-specific and random effects pooled, unadjusted odds ratios (ORs).ResultsThirteen studies fulfilled inclusion criteria: 7 memory clinic cohorts (n = 2,587), 5 symptomatic CAA cohorts (n = 402), and 1 population-based study (n = 1,379). There was no significant overall association between APOE ε4+ and cSS presence or severity. When stratified by clinical setting, APOE ε4+ was associated with cSS in memory clinic (OR 2.10; 95% confidence interval [CI] 1.11–3.99) but not symptomatic CAA patients. The pooled OR showed significantly increased odds of having cSS for APOE ε2+ genotypes (OR 2.42, 95% CI 1.48–3.95) in both patient populations. This association was stronger for disseminated cSS in symptomatic CAA cohorts. In detailed subgroup analyses, APOE ε2/ε2 and APOE ε2/ε4 genotypes were most consistently and strongly associated with cSS presence and severity.ConclusionCAA-related vasculopathic changes and fragility associated with APOE ε2+ allele might have a biologically meaningful role in the pathophysiology and severity of cSS.