Nikolova, Jennifer

Introduction: Although primarily supplied by the vertebrobasilar system, the hippocampus is partially supplied by ipsilateral carotid artery branches through the anterior choroidal artery or a prominent posterior communicating artery. We report a patient with acute hippocampus infarction likely due to symptomatic ipsilateral tandem carotid stenosis and discuss acute vascular-mediated hippocampal injury. Case Report: An 80-year-old female with obesity, dyslipidemia, hypertension, alcohol use disorder, history of breast cancer on letrozole, and traumatic brain injury was brought into our emergency department for 24 hours of confusion. On examination, she exhibited limited registration, recall, and executive dysfunction with otherwise normal language, visuo-spatial orientation, and praxis. Brain MRI showed a small area of diffusion restriction in the anterior right hippocampus with matched FLAIR hyperintensity, consistent with acute infarction. Computed tomography angiogram head and neck showed 90% stenosis of the proximal right internal carotid artery (ICA), <50% narrowing of the proximal left ICA, and moderate bilateral narrowing of the paraclinoid ICAs, all due to calcific atheromatous plaques. The etiology of the hippocampal infarction was suspected embolism from the ipsilateral severe carotid stenosis. Planning for right cervical carotid revascularization ensued. Conclusion: This case highlights the dual hippocampal vascular supply and that hippocampal embolic infarcts could be a sign of a symptomatic severe carotid artery stenosis that may require urgent revascularization for stroke secondary prevention.

Background: Retinal vasculopathy had been reported across the continuum of neurodegeneration. Retinal color fundus photography coupled with automated retinal vascular analysis offers potential to non-invazively screen for Alzheimer’s disease (AD) neurodegeneration. Amyloid positron emission tomography (PET) and apolipoprotein 4 (APOE4) carrier status are known biomarkers of AD risk. Herein, we examined the relationship between retinal vascular fractal dimensions in non-mydriatic color fundus photographs, amyloid-PET burden and APOE4 carrier status in a cohort of cognitively intact individuals. Methods: Our dataset included 91 macula-centered and 39 optic disc-centered images from 96 cognitively intact participants (29% male). 25 (26%) were amyloid-PET positive, defined as amyloid-PET standardized uptake value ratio centiloid cut-off > 20. AutoMorph software automatically determined retinal arteriolar and venular density, tortuosity and width, among other fractal dimensions. To test the effect of amyloid-PET status on the retinal vascular parameters, we used a generalized linear model compensated for age, sex and the interaction between APOE4 carrier and amyloid-PET status. We also compared amyloid-PET positive and negative subjects for vascular fractal dimensions correcting for age and gender. We adjusted for multiple comparisons using the False Discovery Rate correction and reported significant P values less than 0.05. Results: Compared to amyloid-PET negative, cognitively intact amyloid-PET positive cohort had greater mean age (71 vs 66 years, P=0.06), more males (60% vs 35%, P=0.02), more APOE4 carriers (P<0.001), similar vascular risk factors (hypertension, dyslipidemia, diabetes mellitus, smoking, P>0.05 for all) and significantly lower macular vessel tortuosity density (P=0.019). The amyloid-PET positive status had a significant effect on the retinal artery distance tortuosity (corrected P=8.75E-04, β=13.9, 95% CI [7.75-19.99]) and artery squared curvature tortuosity (corrected P=8.91E-10, β=464, 95% CI [359.10-569.15]). Conclusions: Automatically determined retinal vascular fractal dimension on non-mydriatic color fundus photographs predicts amyloid-PET burden in cognitively intact individuals. Future longitudinal studies should asssess the utility of automated quantitative retinal vasculopathy analysis to screen for presymptomatic AD.

AbstractPosttraumatic headache (PTH) is the most common symptom following mild traumatic brain injury (mTBI) (also known as concussion). Migraine and PTH have similar phenotypes, and a migraine-like phenotype is common in PTH. The similarities between both headache types are intriguing and challenge a better understanding of the pathophysiological commonalities involved in migraine and PTH due to mTBI. Here, we review the PTH resting-state functional connectivity literature and compare it to migraine to assess overlap and differences in brain network function between both headache types. Migraine and PTH due to mTBI have overlapping and disease-specific widespread alterations of static and dynamic functional networks involved in pain processing as well as dysfunctional network connections between frontal regions and areas of pain modulation and pain inhibition. Although the PTH functional network literature is still limited, there is some evidence that dysregulation of the top-down pain control system underlies both migraine and PTH. However, disease-specific differences in the functional circuitry are observed as well, which may reflect unique differences in brain architecture and pathophysiology underlying both headache disorders.