{
  "abstract": "Background and Objectives Microgravity eliminates the bipedal human physiological hydrostatic pressure gradient, producing fluid redistribution towards the cranium, internal jugular vein (IJV) flow stasis, and thrombosis. These hemodynamic changes have been linked to the development of Spaceflight Associated Neuro-ocular Syndrome (SANS) which affects around 70% of astronauts during long-duration spaceflights (>30days). With Mars missions requiring 2 - 3 years of spaceflight microgravity exposure, comprehensive understanding of cerebral venous abnormalities affecting astronauts is critical. We conducted a systematic review to characterize the incidence, pathophysiology, clinical significance of spaceflight associated cerebral venous abnormalities. We critique current countermeasures and emerging technologies, and delineate critical knowledge gaps.Methods PubMed, NASA aerospace medicine archives, and google scholar databases were searched through December 2025. Eligible studies included human spaceflight investigations, ground-based analogs (head-down tilt, parabolic flight), animal models, and technology reports addressing cerebral venous hemodynamics, intracranial pressure (ICP), thromboembolism, or SANS. Due to heterogeneity in study design and data reporting we performed qualitative narrative synthesis.Results 87 reports met the inclusion criteria, encompassing fewer than 50 astronauts with inflight venous assessments. Among 11 astronauts evaluated with serial IJV ultrasound on the international space station (ISS), 55% (6/11) exhibited stagnant or retrograde flow, with two asymptomatic IJV thromboses (18% incidence). IJV cross-sectional area increased ~600% in microgravity. Direct ICP measurements during acute weightlessness (n=8) showed pressure of 13±2 mmHg, significantly below supine values (17±2 mmHg) but substantially above upright values on ground (4±1 mmHg). Parabolic flight data demonstrated persistent IJV stagnation at lunar (1/6) and martian (2/5) gravity equivalents. Emerging technologies (TRL 3-7) include AI-guided point-of-care ultrasound (TRL7), wearable ICP monitors (TRL6), and portable low-field MRI (TRL6), and novel venous flow augmentation device (TRL3).Conclusions Cerebral venous abnormalities represent a critical risk during deep space missions, with thrombosis incidence exceeding terrestrial rates. Partial gravity on moon and mars may be potentially insufficient to resolve venous stasis. Major areas that need further validation and investigations include validation of non-invasive ICP monitoring, SANS countermeasure dose optimization, thrombophilia screening protocol, and cerebral venous augmentation device development.Disclosures V. Shenoy: None. B. Ghodke: None. L. Sekhar: None.",
  "authors": [
    {
      "affiliations": [
        "Neurological Surgery, University of Washington, Seattle, WA"
      ],
      "name": "V Shenoy"
    },
    {
      "affiliations": [
        "University of Washington, Seattle, WA"
      ],
      "name": "B Ghodke"
    },
    {
      "affiliations": [
        "Neurological Surgery, University of Washington, Seattle, WA"
      ],
      "name": "L Sekhar"
    }
  ],
  "title": "E-346 Cerebral Venous abnormalities in astronauts in microgravity: systematic review of knowledge gaps, current treatment strategies, and emerging technologies",
  "uid": "76e38221-760c-5f94-b330-dc675da78ece"
}