Benjamin Soares

Background and purpose Emissary veins (EVs) are common incidental radiological findings, and enlarged EVs have been associated with the development of pulsatile tinnitus (PT). The purpose of this study is to further investigate the prevalence and characteristics of EVs in patients with and without PT. Materials and methods We conducted a case-control study of consecutive patients with PT and age- and sex-matched controls who received imaging (primarily CTA, CTV, and MRI) between February 2018 and February 2022. Radiological evaluation was performed by two neuroradiologists and EVs measurements were performed at the point of maximal diameter. For statistical analyses, Mann-Whitney U test was used to compare vein diameters, and Fisher’s exact test was used to compare vein frequencies. Results Condylar and mastoid emissary veins of any diameter were less frequently observed in patients with PT than controls (66% vs. 78%; p < 0.01). The median diameter of mastoid emissary veins (MEVs) was significantly greater in the PT cohort (1 [IQR 1–2] mm vs. 1 [1–1] mm; p < 0.01) but there was no difference in median condylar emissary vein (CEV) diameter (3 [2–4] mm vs. 2 [2-3.5] mm; p = 0.64). Dilated CEVs (≥ 5 mm, 11% vs. 4%; p = 0.02) and MEVs (≥ 2 mm, 30% vs. 13%; p < 0.01) were more common in patients with PT. In both the PT and control cohorts, there was no significant difference in the prevalence of dilated EVs in patients with and without significant internal jugular stenosis (IJVS), transverse sinus stenosis (TSS). Additionally, there was no significant difference in the prevalence of dilated EVs in patients with and without idiopathic intracranial hypertension (IIH) in the PT cohort. Conclusion Dilated CEVs and MEVs were more common in patients with PT compared to controls, while the overall prevalence of CEVs/MEVs was lower in the control cohort.There was no association between the prevalence of dilated EVs and the presence of significant IJVS or TSS in patients with PT or controls.

BACKGROUND AND PURPOSE: The role of internal jugular venous stenosis (IJVS) in the development of pulsatile tinnitus (PT) is unclear. In this study, we aim to assess the prevalence of IJVS and to analyze the associated imaging findings in patients with and without PT. MATERIALS AND METHODS: We conducted a case-control study of consecutive adult patients with PT who underwent imaging evaluation with CT angiogram/CT venogram with contrast between February 2018 and March 2022. Age-and sex-matched controls who received CTA and/or CTV for an indication other than PT, headache, or visual disturbance were included. We compared the clinical and imaging findings between the PT and control groups. The prevalence and severity of IJVS were also analyzed. RESULTS: A total of 148 patients with PT and 98 control patients were included. There was no difference in the prevalence of IJVS between groups (p = 0.19). No difference in stenosis grade was observed between patients with PT and those in the control group with IJVS (p = 0.61). Empty sella turcica, optic nerve tortuosity, optic nerve sheath prominence, transverse sinus stenosis (TSS), and sigmoid sinus wall abnormalities (SSWA) were greater in the PT group than in controls (all p < 0.01). Among PT patients, imaging findings of IIH were not associated with IJVS. Among patients with IJVS, TSS and empty sella turcica were more common in PT patients than controls. CONCLUSIONS: IJVS was common in patients with PT and controls with similar prevalence and severity observed in both groups. TSS and SSWA were significantly more common in PT patients compared to controls. Among PT patients, there was no association between imaging findings of IIH and IJVS. Other causes of PT should be sought before considering intervention for IJVS. ABBREVIATIONS: IIH = idiopathic intracranial hypertension; IJVS = internal jugular venous stenosis; LP = lumbar puncture; PT = pulsatile tinnitus; SSWA = sigmoid sinus wall abnormalities; TSS = transverse sinus stenosis

In light of the potential effects of spaceflight on the anterior segment of the eye, there is a pressing need for anterior segment imaging to be available and accessible to monitor astronauts’ ocular health, including alterations to the cornea and lens. We aim to highlight the clinical basis and need for anterior segment imaging for astronauts. We explore the impacts of spaceflight-associated hazards, including microgravity and radiation, on astronauts’ risk of developing anterior segment pathology including risk of ocular trauma, infection, dry eye symptoms, cataracts, and possibly additional pathologies from increased radiation exposure. Such risks highlight the potential value that longitudinal assessment of anterior ocular structures would offer in future spaceflight missions. Specifically, anterior segment imaging would enable evaluations of corneal morphology, including longitudinal monitoring for microgravity-induced changes, and evaluation of interventions that aim to preserve anterior segment health during spaceflight. Lastly, non-invasive anterior segment imaging allows for unique insights into astronaut ocular health and can be performed routinely through modalities such as anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). We discuss these modalities and their implications for astronaut health during future spaceflight.

Ocular health is currently a major concern for astronauts on current and future long-duration spaceflight missions. Spaceflight-associated neuro-ocular syndrome (SANS) is a collection of ophthalmic and neurologic findings that is one potential physiologic barrier to interplanetary spaceflight. Since its initial report in 2011, our understanding of SANS has advanced considerably, with a primary focus on posterior ocular imaging including fundus photography and optical coherence tomography. However, there may be changes to the anterior segment that have not been identified. Additional concerns to ocular health in space include corneal damage and radiation-induced cataract formation. Given these concerns, precision anterior segment imaging of the eye would be a valuable addition to future long-duration spaceflights. The purpose of this paper is to review ultrasound biomicroscopy (UBM) and its potential as a noninvasive, efficient imaging modality for spaceflight. The analysis of UBM for spaceflight is not well defined in the literature, and such technology may help to provide further insights into the overall anatomical changes in the eye in microgravity.