new study suggests that gadolinium used during MRI imaging in stroke patients
leaks into the eyes and can provide clues about the stroke
contrast used during MRI in stroke patients leaks into the eyes.
- This indicates
that the blood vessels of the eyes become leaky following a stroke.
- Therefore, an eye
examination following a stroke using a special dye could obviate the need
for an MRI scan in the future.
. The study
was published in Neurology.
The study evaluated the
imaging) reports of 167 stroke patients. Some patients did not receive
treatment before the test while others were treated with the clot-dissolving
drug called tissue plasminogen activator. The MRI was first done without and
then with a contrast dye called gadolinium which was injected into the blood.
The use of a contrast allows the easy detection of the damaged area of the
brain. The test was repeated 2 and 24 hours after the initial MRI. The
scientists found that:
- Leakage of
gadolinium occurred into the eyes of 76% individuals.
- There also
appeared to be a specific pattern for the leakage. The MRI done after 2
hours showed leakage in the aqueous chamber, the part of the eye in front
of the iris in 67% individuals, in the vitreous chamber, the part of the
eye behind the iris in 6% patients, and in both the aqueous and the
vitreous chamber in 27% of patients. Patients with gadolinium in both the
chambers had a larger part of the brain affected by the stroke.
- The MRI performed
at 24 hours detected the leakage in the vitreous chamber of the eyes in
75% patients, and in both the chambers in 6% patients. In older patients,
patients with greater affliction of the white matter of the brain due to
aging, and patients with hypertension, gadolinium
was detected more commonly in the vitreous chamber at 24 hours.
The leakage of
gadolinium, however, could not be associated with the extent of the disability
caused by the stroke.
‘Examination of the eyes with a special dye could give clues on the extent of brain damage caused due to stroke in the future.’
Gadolinium does not leak
into the eyes of individuals without brain damage. The scientists therefore
suggest that the stroke could make the blood vessels of the eyes leakier and
therefore allows the leakage of gadolinium into the eyes.
studies on the phenomenon could reveal ways in which, using a special dye that
accumulates in the eye in stroke patients similar to gadolinium, an eye
examination will be able to provide clues into the severity of brain damage
caused by the stroke
imaging (MRI) is an imaging test during which images of the brain or other
parts of the body are obtained using a magnetic field. A contrast is sometimes
injected to highlight the damaged part. In a normal brain, leakage of the dye
through the blood vessels into the brain does not occur. Damage to the brain
on the other hand, allows the
contrast to enter the brain and settle down in damaged areas, thus enabling
easy detection of the damaged parts.
- Hitomi et al. Blood-ocular barrier disruption in acute stroke patients. Neurology. February 7, 2018. doi: 10.1212/WNL.0000000000005123.