In MRI scans of a stroke patient’s eyes yield information about strokes

MRI: Gadolinium, used to improve images, leaked into the eyes of stroke patients.

Curious bright spots in the eyes on stroke patients’ brain images nor can alter the way these individuals are assessed and treated.

A study was in Neurology wrote that the eyes glow so brightly on these images due to gadolinium, a harmless, transparent chemical often given to patients during magnetic resonance imaging (MRI) scans to highlight abnormalities in the brain.

In healthy individuals, gadolinium remains in the blood stream and is filtered out by the kidneys. However, when someone has experienced damage to the blood-brain barrier, which controls whether substances in the blood can enter the brain, gadolinium leaks into the brain, creating bright spots that mark the location of brain damage.

A stroke can also compromise the blood-ocular barrier and that the gadolinium that leaked into a patient’s eyes could provide information about his or her stroke.

The researchers performed MRI scans on 167 stroke patients upon admission to the hospital without administering gadolinium and compared them to scans taken using gadolinium two hours and 24 hours later.

Because gadolinium is transparent, it did not affect patients’ vision and could only be detected with MRI scans. Roughly three-quarters of the patients experienced gadolinium leakage into their eyes on one of the scans, with 66 percent showing it on the two-hour scan and 75 percent on the 24-hour scan. The phenomenon was present in both untreated patients and patients who received tPA, to dissolve the blood clot responsible for their strokes.

Gadolinium was typically present in the front part of the eye, called the aqueous chamber, after two hours, and the vitreous chamber, after 24 hours.

Patients showing gadolinium in the vitreous chamber at the later timepoint tended to be of older age, have a history of hypertension, and have more bright spots on their brain scans, called white matter hyperintensities, that are associated with brain aging and decreased cognitive function.

In a minority of patients, the two-hour scan showed gadolinium in both eye chambers. The strokes in those patients tended to affect a larger portion of the brain and cause even more damage to the blood-brain barrier than the strokes of patients with a slower pattern of gadolinium leakage or no leakage at all.

The findings raise the possibility that, in the future, clinicians could administer a substance to patients that would collect in the eye just like gadolinium and quickly yield important information about their strokes without the need for an MRI.