Magnetic resonance imaging of COVID-19 anosmic patients reveals abnormalities of the olfactory bulb: Preliminary prospective study.

• COVID-19 patients with total loss of smell have more olfactory bulb abnormalities at the magnetic resonance imaging than patients without loss of smell. • The olfactory bulb MRI abnormalities may be objectified through a signal intensity ratio measurement that is calculated between the average signals of the olfactory bulb and the frontal white matter. • The loss of smell is probably due to olfactory bulb inflammation related to virus spread.