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Mr‐derived cerebral spinal fluid hydrodynamics as a marker and a risk factor for intracranial hypertension in astronauts exposed to microgravity
Author(s) -
Kramer Larry A.,
Hasan Khader M.,
Sargsyan Ashot E.,
Wolinsky Jerry S.,
Hamilton Douglas R.,
Riascos Roy F.,
Carson William K.,
Heimbigner Jared,
Patel Vipulkumar S.,
Romo Seferino,
Otto Christian
Publication year - 2015
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.24923
Subject(s) - medicine , cerebral spinal fluid , magnetic resonance imaging , flattening , cardiology , anesthesia , radiology , physics , astronomy
Purpose To quantify the change in cerebral spinal fluid (CSF) production rate and maximum systolic velocity in astronauts before and after exposure to microgravity and identify any physiologic trend and/or risk factor related to intracranial hypertension. Materials and Methods Following Institutional Review Board (IRB) approval, with waiver of informed consent, a retrospective review of 27 astronauts imaged at 3T was done. Qualitative analysis was performed on T 2 ‐weighted axial images through the orbits for degree of flattening of the posterior globe according to the following grades: 0 = none, 1 = mild, 2 = moderate, and 3 = severe. One grade level change postflight was considered significant for exposure to intracranial hypertension. CSF production rate and maximum systolic velocity was calculated from cine phase‐contrast magnetic resonance imaging and compared to seven healthy controls. Results Fourteen astronauts were studied. The preflight CSF production rate in astronauts was similar to controls ( P = 0.83). Six astronauts with significant posterior globe flattening demonstrated a 70% increase in CSF production rate postflight compared to baseline ( P = 0.01). There was a significant increase in CSF maximum systolic velocity in the subgroup without posterior globe flattening ( P = 0.01). Conclusion The increased postflight CSF production rate in astronauts with positive flattening is compatible with the hypothesis of microgravity‐induced intracranial hypertension inferring downregulation in CSF production in microgravity that is upregulated upon return to normal gravity. Increased postflight CSF maximum systolic velocity in astronauts with negative flattening suggests increased craniospinal compliance and a potential negative risk factor to microgravity‐induced intracranial hypertension. J. MAGN. RESON. IMAGING 2015;42:1560–1571.