Features of radiation diagnosis of COVID-associated mucormycosis of the paranasal sinuses: a prospective study

Introduction: Mucormycosis is a severe infection that mainly develops in immunocompromised patients. During the COVID- 19 pandemic, there was an increase in the incidence of mucormycosis, high prevalence was observed in many countries of the world, for example, in India. The number of publications on mucormycosis in electronic libraries has increased more than 1.5 times over the past four years. Patients with COVID-associated mucormycosis (COVID-M) predominantly develop lesions of the paranasal sinuses — up to 96%. Mucormycosis of the paranasal sinuses is characterized by high disability and mortality of up to 80%. Objective : To analyze the results of multispiral computed tomography (MSCT) and magnetic resonance imaging (MRI) in patients with COVID-associated rhinocerebral mucormycosis to improve the effectiveness of disease diagnosis. Materials and methods: The registry of patients with mucormycosis included 100 patients with COVID-associated paranasal sinus mucormycosis. The criteria of EORTC/MSG, 2020 were used to make the diagnosis of «invasive mycosis». Retrospectively, using the Weasis v4.5.0 program, the multispiral computed tomography data of 41 patients were analyzed in dynamics. The median age of the patients was 61 years (22–83), 56% of them men. CT-studies were performed using a GE Bright Speed 16 tomograph, GE Revolution HD, Philips Ingenuity Core 64, Aquilion PRIME 1. Statistics: Statistical data analysis was performed using the Microsoft Office Excel 2019. Survival analysis was performed using the Kaplan-Mayer method. Results: The main clinical symptoms were swelling of the soft tissues of the face and eyes (93%), local pain syndrome (88%), facial numbness (78%), paresthesia (76%), visual impairment (66%). Thickening of the mucous membranes (100%) was observed in the nasal cavity with the formation of necrotic masses and a characteristic «black scab» (90%). The main radiological signs were: hypertrophy of the mucous membranes of the paranasal sinus — 100%, destructive changes in the walls of the sinuses and bones of the skull — 100%; edema, thickening of the soft tissues of the face, orbit and brain — 93%. Destructive changes of the maxillary sinuses were detected in 100% of patients, the walls of the orbits — 95%, the latticed bone — 93%, the maxilla — 85%, the walls of the main sinus and the sphenoid bone — 83%, the frontal sinuses — 37%. The lesion of the optic nerve is in 66%. According to the central nervous system, damage to the frontal lobe was detected in 32% of cases, damage to the temporal lobe — 15%. Cavernous sinus thrombosis — 46%. In case of orbital damage, CT-signs were determined on day 12 (median 12.5±4.9 days) from the onset of clinical manifestations, involvement of the optic nerve in the infectious process also on day 12 (median 12±4.1 days). CT-changes from the central nervous system were observed on day 18 (median 18±10.45 days). The survival rate of patients within 3 months was 88%, and within 1 year — 78%. Discussion : The main underlying diseases in mucormycosis today are COVID-19 (46%) and oncohematological pathology (37%). When analyzing the risk factors for the development of rhinocerebral mucormycosis, the main importance is the presence of concomitant diabetes mellitus (88%), as well as long-term use of glucocorticosteroids (GCS) in high doses (90%). The main CT-signs of rhinocerebral mucormycosis were the destruction of the walls of the paranasal sinuses and cranial bones, which occurs on days 7–12 from the onset of the first clinical symptoms. Conclusion: Radiation examinations are the leading imaging methods for rhinocerebral mucormycosis. The examination protocol must include a MSCT scan of the paranasal sinuses and an MRI scan of the brain. Early radiological diagnostics reduces mortality and disability of patients.