Cerebrovascular Effects of Lower Body Negative Pressure at 3T MRI: Implications for Long‐Duration Space Travel

Background Optic disc edema develops in most astronauts during long‐duration spaceflight. It is hypothesized to result from weightlessness‐induced venous congestion of the head and neck and is an unresolved health risk of space travel. Purpose Determine if short‐term application of lower body negati...

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Bibliographic Details
Published in:Journal of magnetic resonance imaging 2022-09, Vol.56 (3), p.873-881
Main Authors: Kramer, Larry A., Hasan, Khader M., Gabr, Refaat E., Macias, Brandon R., Marshall‐Goebel, Karina, Laurie, Steven S., Hargens, Alan R.
Format: Article
Language:English
Subjects:
Airtightness
Astronauts
Blood flow
brain perfusion
cerebral artery flow and microgravity
Edema
Extremities
Field strength
Flow velocity
Health risks
Heart rate
internal jugular vein flow
Jugular vein
Lower body negative pressure
Magnetic resonance imaging
MRI
Perfusion
Posture
Space flight
Spin labeling
Statistical analysis
Statistical tests
Stroke volume
Substantia alba
Travel
Weightlessness
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Summary:Background Optic disc edema develops in most astronauts during long‐duration spaceflight. It is hypothesized to result from weightlessness‐induced venous congestion of the head and neck and is an unresolved health risk of space travel. Purpose Determine if short‐term application of lower body negative pressure (LBNP) could reduce internal jugular vein (IJV) expansion associated with the supine posture without negatively impacting cerebral perfusion or causing IJV flow stasis. Study Type Prospective. Subjects Nine healthy volunteers (six women). Field Strength/Sequence 3T/cine two‐dimensional phase‐contrast gradient echo; pseudo‐continuous arterial spin labeling single‐shot gradient echo echo‐planar. Assessment The study was performed with two sequential conditions in randomized order: supine posture and supine posture with 25 mmHg LBNP (LBNP25). LBNP was achieved by enclosing the lower extremities in a semi‐airtight acrylic chamber connected to a vacuum. Heart rate, bulk cerebrovasculature flow, IJV cross‐sectional area, fractional IJV outflow relative to arterial inflow, and cerebral perfusion were assessed in each condition. Statistical Tests Paired t‐tests were used to compare measurement means across conditions. Significance was defined as P 
ISSN:1053-1807
1522-2586
DOI:10.1002/jmri.28102