News | March 15, 2012

MRI Shows Prolonged Space Travel Causes Brain, Eye Abnormalities in Astronauts

March 15, 2012 - Magnetic resonance imaging (MRI) of the eyes and brains of 27 astronauts who have spent prolonged periods of time in space revealed optical abnormalities similar to those that can occur in intracranial hypertension of unknown cause, a potentially serious condition in which pressure builds within the skull. A retrospective analysis of the MRI data appears online in the journal Radiology.

A team of researchers performed MRIs and analyzed the data on the 27 astronauts, each of whom were exposed to microgravity, or zero gravity, for an average of 108 days while on space shuttle missions and/or the International Space Station (ISS), a habitable research facility that has been orbiting the earth since 1998. Eight of the 27 astronauts underwent a second MRI exam after a second space mission that lasted an average of 39 days.

“The MRI findings revealed various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity also seen with idiopathic intracranial hypertension,” said Larry A. Kramer, M.D., professor of diagnostic and interventional imaging at The University of Texas Medical School at Houston. “These changes that occur during exposure to microgravity may help scientists to better understand the mechanisms responsible for intracranial hypertension in non-space traveling patients.”

Among astronauts with more than 30 days of cumulative lifetime exposure to microgravity, findings included expansion of the cerebral spinal fluid space surrounding the optic nerve in nine of the 27 (33 percent) astronauts, flattening of the rear of the eyeball in six (22 percent), bulging of the optic nerve in four (15 percent) and changes in the pituitary gland and its connection to the brain in three (11 percent) of the astronauts. The pituitary gland secretes and stores hormones that regulate a variety of important body functions.

The same types of abnormalities are observed in cases of intracranial hypertension where no cause can be found for increased pressure around the brain. The pressure causes swelling of the juncture between the optic nerve and the eyeball, which can result in visual impairment.

Bone mineral loss and muscle atrophy are some of the known effects of zero gravity on astronauts. With the onset of longer excursions in space afforded by the ISS, visual changes have also been observed and are now being studied.

“Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel,” Kramer said.

William J. Tarver, M.D., M.P.H., chief of flight medicine clinic at NASA/Johnson Space Center, said the agency has noted changes in vision in some ISS astronauts, the origin of which is not yet fully understood. No astronauts have been considered ineligible for space flight duties as a result of the findings, which he said are suspicious but not conclusive of intracranial hypertension.

“NASA has placed this problem high on its list of human risks, has initiated a comprehensive program to study its mechanisms and implications, and will continue to closely monitor the situation,” Tarver said.

For more information: http://radiology.rsna.org

Related Content

First FDA-Approved Study of Focused Ultrasound to Open Blood-Brain Barrier
News | Focused Ultrasound Therapy | August 21, 2018
In the first such clinical trial in the United States, physician-scientists with the University of Maryland School of...
Doctor-Patient Discussions Neglect Potential Harms of Lung Cancer Screening
News | Lung Cancer | August 15, 2018
August 15, 2018 — Although national guidelines advise doctors to discuss the benefits and harms of...
Videos | Magnetic Resonance Imaging (MRI) | August 13, 2018
Haojie Wang, M.D., director of advanced cardiovascular MRI and a member of the heart valve clinic at Baylor Scott Whi
ACR LI-RADS Steering Committee Releases New Version of CT/MRI LI-RADS
News | Clinical Decision Support | August 13, 2018
August 13, 2018 — The American College of Radiology Liver Imaging Reporting and Data System (LI-RADS) steering commit
Indiana Hospital Installs First Vantage Titan/Zen Edition 1.5T MRI in U.S.
News | Magnetic Resonance Imaging (MRI) | August 10, 2018
Patients in Pulaski County, Ind., now have access to quiet, comfortable magnetic resonance (MR) exams thanks to the...
3T MRI Installed at The London Clinic Through Hospital Roof

Image courtesy of The London Clinic

News | Magnetic Resonance Imaging (MRI) | August 08, 2018
Patients at The London Clinic, a private hospital and charity, will be the first in the United Kingdom to access the...
Cardiac Imaging Reveals Roots of Preeclampsia Damage in Pregnant Women
News | Women's Health | August 07, 2018
Johns Hopkins researchers say a heart imaging study of scores of pregnant women with the most severe and dangerous form...
Cardiac Monitoring a Higher Priority for High-Risk Breast Cancer Patients
News | Cardio-oncology | August 07, 2018
August 7, 2018 — While heart failure is an uncommon complication of...
Videos | Contrast Media | August 03, 2018
Lawrence Tanenbaum, M.D., FACR, vice president and director of advanced imaging at RadNet, discusses the latest resea
Videos | Magnetic Resonance Imaging (MRI) | August 01, 2018
Robert Junk and Tobias Gilk, MRSO, MRSE, of architectural firm RAD-Planning, discuss the different types of safety ha
Overlay Init