Imaging findings using a combined MRI/CT protocol to identify the "entire iceberg" in post-COVID-19 mucormycosis presenting clinically as only "the tip".

ABSTRACT

AIM: To analyse combined computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of invasive rhino-orbital mucormycosis (IROM) in post-COVID-19 infection patients for accurate diagnosis and delineation of the extent of involvement. MATERIALS AND METHODS: A retrospective analysis was undertaken of 50 patients who developed IROM post-COVID-19 infection who underwent combined CT/MRI evaluation. RESULTS: The age range of the 50 affected patients was 23-73 years. Out of these, 41 were diabetic. CT/MRI showed predominant involvement of the maxillary (n=26) and ethmoid (n=19) sinuses. Extension of disease to the orbit (n=35), cavernous sinus (n=18), hard palate (n=15), skull base (n=8), and intracranial involvement (n=3) was seen. Perineural spread of the disease was analysed along all divisions of the trigeminal nerve and its branches. MRI showed T2-hypointense soft-tissue thickening with heterogeneous contrast enhancement with corresponding hyperdensities on CT diagnosing the presence of fungal elements. CONCLUSION: Clinicians should be aware of the possibility of IROM post-COVID-19 infection. Conjunctive use of CT, which depicts bone destruction and other reactive bony changes along with MRI, which reveals characteristic findings of soft-tissue thickening of the involved sinuses with extension of disease to the orbits, cavernous sinus, dura, hard palate, skull base, and intracranial structures. Accurate diagnosis and early recognition of the disease and its extension with appropriate use of these techniques helps to initiate appropriate and timely treatment, which is vital to prevent a fatal outcome.