In a group of COVID-19 patients at a Paris hospital, half showed pathological MRI findings, according to a study published this month in Radiology.

Between March 23 and May 7, 2020, researchers at the Pitié-Salpêtrière University Hospital analyzed 73 adult COVID-19 patients who had no history of neurological conditions. After assessing MRI images of the patients, the researchers determined that 43 had pathological findings, including 17 with acute ischemic infarcts, one with deep venous thrombosis, eight with multiple microhemorrhages, 22 with perfusion abnormalities, and three with “restricted diffusion foci within the corpus callosum consistent with cytotoxic legions of the corpus callosum.”

“This pattern of brain damage has some similarities to that seen in encephalitis lethargica (EL) also known as Von Economo disease,” wrote the study authors. EL was a symptom reported during the 1918 flu.