Post-COVID-19 acute invasive fungal rhinosinusitis: a systematic radiological approach in the light of clinico-surgical characteristics

BACKGROUND: The objective is to describe the radiological imaging findings of post-COVID-19 acute invasive fungal rhinosinusitis (AIFRS), being familiar with the wide variety of imaging spectrum, thus raising the suspicion for early diagnosis. Methods: In this retrospective study, we reviewed the imaging findings in 54 patients with proven post-COVID-19 AIFRS who underwent endoscopic/surgical debridement from April 2020 to September 2021. Most of these patients presented with facial or orbital swelling or facial pain. Medical records with a special emphasis on radiological imaging (50 NCCT of the paranasal sinuses and 17 MRIs of the orbit) were reviewed regarding the degree of mucosal disease of sinuses, nasal cavity, and nasopharynx, extra sinus soft tissue infiltration, especially orbital and cerebral extension (parenchymal, cavernous sinus, vascular or neuro-invasion). RESULTS: We reported findings in 54 patients with post-COVID-19 AIFRS, of whom 30 were men and 24 were women with a mean age of 48.06. Unexpectedly, infiltration of pterygopalatine fossa was found to precede mucosal opacification of sinuses nasal cavity and affection of nasopharynx. Out of 54 patients, 49 showed inflammatory changes involving pterygopalatine fossa, 29.6% of patients showed infiltration of orbital tissues, 22 patients suffered from a fungal invasion of the cavernous sinus and 3 patients had carotid artery involvement. CONCLUSIONS: Imaging findings of AIFRS significantly vary from subtle mucosal thickening of paranasal sinuses, up to orbital and intracranial extension with vascular thrombosis and neuroinvasion. The hallmark inflammatory tissue infiltration into the pterygopalatine fossa and facial soft tissue may precede mucosal disease.