Van Ombergen and 21 other researchers, mostly in Russia, report that long-duration spaceflight induces detrimental changes in human physiology due to microgravity. One example is a cephalic fluid shift. They prospectively investigated the quantitative changes in cerebrospinal fluid (CSF) volume of the brain ventricular regions in space crew by means of a region of interest, observer-independent analysis on structural brain MRI scans. MRI scans were collected before the mission, shortly after and 7 mo after return to Earth. They found a significant increase in lateral and third ventricles at post-flight and a trend to normalization at follow-up, but still significantly increased ventricular volumes. The observed spatiotemporal pattern of CSF compartment enlargement and recovery points to a reduced CSF resorption in microgravity as the underlying cause.
Long-duration spaceflight is associated with several factors that can induce detrimental changes across many human physiological systems. An example hereof is the cephalic fluid shift that occurs immediately upon entering a microgravity environment because of the loss of hydrostatic pressures within the caudocranial fluid columns of the body (e.g., arterial and venous structures). It has been suggested that this fluid shift is associated with ocular and visual acuity changes, a clinical syndrome that has been coined Visual Impairment Intracranial Pressure (VIIP) syndrome and, more recently, redefined as Spaceflight-Associated Neuro-ocular Syndrome (SANS). VIIP or SANS has been reported to present with globe flattening, choroidal folds, optic disk edema, and a hyperopic visual shift (see refs. for an overview), with a potential risk of permanent visual acuity changes. The exact mechanisms underlying these visual changes related to long-duration spaceflight, however, are still unclear.
Previous studies have observed a cerebrospinal fluid (CSF) compartment enlargement, including the subarachnoid space, directly after long-duration spaceflight. However, to date, no coherent imaging dataset and observer-independent analysis are available to quantify CSF volume changes longitudinally including a follow-up period longer than 1 mo after return to Earth.
In this prospective study, they therefore aimed to assess and quantify ventricular volume changes in cosmonauts and matched controls on a group level by means of an observer-independent region-of-interest analysis of CSF spaces derived from structural MRI brain scans before, shortly after, and 7 mo after long-duration spaceflight. They compared these findings together with other published analyses to try to unravel the underlying dynamics in CSF compartment changes.
Managed by I2M Consulting, LLC