Intracranial Effects of Microgravity: A Prospective Longitudinal MRI Study

Area of Science:

• Neuroscience
• Space Medicine
• Radiology

Background:

• Astronauts experience ocular changes post-spaceflight, possibly linked to elevated intracranial pressure.
• The exact causes of these intracranial pressure changes during spaceflight remain unclear.

Purpose of the Study:

• To investigate microgravity's intracranial effects by measuring volumetric, pituitary, and cerebrospinal fluid (CSF) hydrodynamics changes.
• To develop a comprehensive model for post-flight recovery of these parameters.

Main Methods:

• Prospective longitudinal MRI study of astronauts before and up to 360 days after long-duration spaceflight.
• Quantification of intracranial volumetry, aqueductal CSF hydrodynamics (velocity, stroke volume), and pituitary morphology.

Main Results:

• Increased brain, white matter, lateral ventricle, and total brain/CSF volumes were observed post-flight.
• Elevated aqueductal stroke volume and CSF peak-to-peak velocity magnitude were noted.
• Persistent brain and CSF volume expansion and pituitary deformation were evident up to 1 year post-flight.

Conclusions:

• Long-duration spaceflight induces pituitary deformation and alters CSF hydrodynamics.
• Significant expansion of brain and CSF volumes persists for at least one year, suggesting permanent intracranial alterations.