{
  "abstract": "Background Recent progress in orbital spaceflight has enabled civilian space travel which is poised to accelerate over the coming decades. This expansion of commercial spaceflight has introduced medically unscreened civilian populations to high G-force acceleration during the launch and descent phase of the rocket that is known to profoundly influence cerebral hemodynamics. Unlike trained astronauts who undergo rigorous cerebrovascular evaluation, civilian spaceflight participants have no federally mandated neurological screening under current FAA regulations. In this systematic review we aimed to 1. characterize the cerebrovascular risks of high-G exposure during commercial spaceflight, 2. evaluate preexisting cerebrovascular conditions as risk modifiers, 3. assess existing neuroimaging capabilities and screening protocols, and 4. identify critical knowledge gaps requiring investigation before evidence-based screening standards can be established.Methods We conducted a systematic literature search across PubMed, NASA aerospace medicine archives, and google scholar database through December 2025 using the following search terms: cerebrovascular physiology under acceleration, G-induced loss of consciousness, spaceflight associated neuro-ocular syndrome (SANS), cerebral autoregulation in space, commercial spaceflight screening protocols, and neuroimaging screening for astronauts. Studies meeting inclusion criteria were human centrifuge trials, inflight physiological measurements, computational hemodynamic models, animal centrifugation experiments, biomarker analyses, and regulatory policy documents. Data on G-force tolerance thresholds, cerebral blood flow changes, jugular venous hemodynamics, and neuroimaging was collected and analyzed.Results Pooled physiological data demonstrate that high G-force acceleration reduces mean cerebral blood flow velocity by approximately 48% , with high-G induced loss of consciousness occurring within 4-6 seconds of effective cerebral circulatory arrest. Commercial spaceflight exposes individuals to 3 - 6G acceleration which is thought to be tolerable ranges for healthy subjects, although 69% of subjects experienced dimming of vision (grayout) during suborbital launch and reentry simulation. Microgravity produces 7 fold internal jugular venous distension, with flow stagnation or retrograde flow developing in 55% of ISS astronauts. High-G exposure increased wall shear stress under computational high G-loading models. Current 3Tesla MR angiography achieves very high (>90%) sensitivity for cerebral aneurysm detection. No standardized cerebrovascular screening protocol exists for civilians during commercial spaceflights.Conclusions Significant gaps exist between the cerebrovascular risks of civilian spaceflight and the absence of mandatory neuroimaging screening. We propose a framework based on risk stratification that includes brain MRI, intracranial MR angiography, and perfusion imaging screening for orbital missions in participants aged > 40yrs with cardiovascular risk factors. We identify 2 priority research gaps which are key to establish evidence-based screening protocols including patient-specific computational fluid dynamics (CFD) modeling of cerebral hemodynamics under spaceflight acceleration, and characterization of cerebral autoregulation during microgravity to atmospheric reentry transitions.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-230 Cerebrovascular considerations for civilian spaceflight: modeling risks of high G exposure and a call for developing standardized neuroimaging screening protocols for civilian space tourism",
  "uid": "595fe8b9-3667-5c39-926b-2c2a50c12a9b"
}