Neuroimaging mimics of anoxic brain injury: A review.

Diffuse cortical diffusion changes on magnetic resonance imaging (MRI) are characteristically ascribed to global cerebral anoxia, typically after cardiac arrest. Far from being pathognomonic, however, this neuroimaging finding is relatively nonspecific, and can manifest in a myriad of disease states including hypoxia, metabolic derangements, infections, seizure, toxic exposures, and neuroinflammation. While these various conditions can all produce a neuroimaging pattern of widespread cortical diffusion restriction, many of these underlying causes do have subtly unique imaging features that are appreciable on MRI and can be of clinical and diagnostic utility. Specific populations of neurons are variably sensitive to certain types of injury, whether due to differences in perfusion, receptor type density, or the unique tropisms of infectious organisms. In this narrative review, we discuss a number of distinct etiologies of diffuse cortical diffusion restriction on MRI, the unique pathophysiologies responsible for tissue injury, and the resulting neuroimaging characteristics that can be of assistance in differentiating them. As widespread cortical injury from any cause often presents with altered mental status or coma, the differential diagnosis can be enhanced with rapid acquisition of MRI when clinical history or detailed physical examination is limited. In such settings, the distinct imaging features discussed in this article are of interest to both the clinician and the radiologist.

Have geopolitics influenced decisions on American health foreign assistance efforts during the Obama presidency?

BACKGROUND: This study sought to characterize the possible relationship between US geopolitical priorities and annual decisions on health foreign assistance among recipient nations between 2009 and 2016. METHODS: Data on total planned United States (US) foreign aid and health aid were collected for the 194 member nations of the World Health Organization (WHO) from publicly available databases. Trends in per-capita spending were examined between 2009 and 2016 across the six regions of the WHO (Africa, Americas, Eastern Mediterranean, Europe, Southeast Asia, and the Western Pacific). Data on US national security threats were obtained from the Council on Foreign Relations' annual Preventive Priorities Survey. Multivariable regression models were fitted specifying planned health aid as the dependent variable and threat level of a recipient aid nation as the primary independent variable. RESULTS: Across the aggregate 80 planned recipient countries of US health aid over the duration of the study period, cumulative planned per-capita spending was stable (US$ 0.65 in both 2009 and 2016). The number of annual planned recipients of this aid declined from 74 in 2009 to 56 in 2016 (24.3% decline), with planned allocations decreasing in the Americas, Eastern Mediterranean, and Europe; corresponding increases were observed in Africa, Southeast Asia, and the Western Pacific. Regression analyses demonstrated a dose-response, whereby higher levels of threat were associated with larger declines in planned spending (critical threat nations: b = -3.81; 95% confidence interval (CI) -5.84 to -1.78, P ≤ 0.001) and one-year lagged (critical threat nations: b = -3.91; 95% CI, -5.94 to -1.88, P ≤ 0.001) analyses. CONCLUSIONS: Higher threat levels are associated with less health aid. This is a novel finding, as prior studies have demonstrated a strong association between national security considerations and decisions on development aid.

Has development assistance for health facilitated the rise of more peaceful societies in sub-Saharan Africa?

Growing evidence suggests that health aid can serve humanitarian and diplomatic ends. This study utilised the Fragile States Index (FSI) for the 47 nations of the World Health Organizations' Africa region for the years 2005-2014 and data on health and non-health development aid spending from the United States (US) for those same years. Absolute amounts of health and non-health aid flows from the US were used as predictors of state fragility. We used time-lagged, fixed-effects multivariable regression modelling with change in FSI as the outcome of interest. The highest quartile of US health aid per capita spending (≥$4.00 per capita) was associated with a large and immediate decline in level of state fragility (b = -7.57; 95% CI, -14.6 to -0.51, P = 0.04). A dose-response effect was observed in the primary analysis, with increasing levels of spending associated with greater declines in fragility. Health per-capita expenditures were correlated with improved fragility scores across all lagged intervals and spending quartiles. The association of US health aid with immediate improvements in metrics of state stability across sub-Saharan Africa is a novel finding. This effect is possibly explained by our observations that relative to non-health aid, US health expenditures were larger and more targeted.