MRI Evaluation of Rhino-orbito-cerebral Mucormycosis in Post COVID-19 Patients: A Cross-sectional Study

Abstract

Introduction: Mucormycosis is the common cause of invasive fungal sinusitis in post Coronavirus Disease-2019 (COVID-19) patient. Mucormycosis is a life-threatening infection with a death rate of >50%. Early detection is critical for determining the amount of infection dissemination, as medical and surgical intervention can reduce death and morbidity. Aim: To evaluate the Magnetic Resonance Imaging (MRI) findings of Rhino-Orbito-Cerebral Mucormycosis (ROCM) in the post COVID-19 patients to detect the extent of the disease and complications. Materials and Methods: This was the retrospective cross- sectional analysis of medical records of 93 patients admitted from 1st June 2021 to 31st July 2021 in tertiary care centre with documented history of COVID-19 infection with clinically suspected and histopathologically confirmed ROCM retrieved for the study. Radiological findings such as involvement of Paranasal Sinus (PNS), intracranial extension, extrasinus extension, orbit, brain parenchyma, perineural extension in ROCM were recorded. Results: Records of total 93 patients (65 males and 28 females; aged between 20-80 years) were studied. The MRI findings revealed, the most common sinus involved was ethmoid sinus (n=92, 98.92%) followed by maxillary (n=90, 96.77%), sphenoid (n=76, 81.72%) and frontal sinus (n=61, 65.59%). There was an involvement of infratemporal and pterygopalatine fossa (n=73, 78.49%), orbit (n=58, 62.36%), cavernous sinus (n=22, 23.65%), Internal Carotid Artery (ICA) (n=12, 12.90%), cranial nerves (n=6, 6.45%), brain parenchyma (n=22, 23.65%) and skull base (n=1, 1.07%). MRI showed T2 isointense to hypointense mucosal thickening and heterogeneous postcontrast enhancement as the most common finding. The mucosa was hypointense on T1W images in all cases (100%). Hypo to isointense components in thickened hyperintense mucosa on T2W images was seen in 77 cases (82.79%). Thickened hyperintense mucosa on T2W images was seen in rest of the 16 (17.20%) cases. Conclusion: In clinically suspected post COVID-19 ROCM cases with typical imaging features (like mucosal thickening with hypointense components on T2W images, demonstration of spread beyond the sinus walls and presence of angioinvasion), even before microbiology or histopathology establish the diagnosis, empirical antifungal medication might be initiated. MRI plays important role in the evaluation of extent of the disease and planning treatment.