Magnetic resonance imaging in COVID-19-associated acute invasive fungal rhinosinusitis - Diagnosis and beyond.

Contrast-enhanced MRI must be performed in all patients with suspected AIFRS as non-contrast MRI fails to demonstrate tissue necrosis and CT fails to demonstrate extrasinosal disease across intact bony walls. Orbital apex, pterygopalatine fossa, and the cavernous sinuses form important pathways for disease spread to the skull base and intracranial compartment. While cerebritis, intracranial abscesses, and infarcts can be seen early in the disease due to the angioinvasive nature, perineural spread and skull base infiltration are seen 3-4 weeks after disease onset. Exaggerated soft-tissue enhancement in the post-operative bed after debridement can be a normal finding and must not be interpreted as disease progression.