Imaging findings in invasive rhino-orbito-cerebral mucormycosis in post-COVID-19 patients

Abstract

Rhino-orbito-cerebral mucormycosis (ROCM) is a life-threatening addition to the COVID-19 disease spectrum and is caused by an angioinvasive saprophytic opportunistic fungus. Early diagnosis is important to avoid disease spread and mortality. Contrast-enhanced magnetic resonance imaging plays a major role in detection of intraorbital and intracranial extension. We present imaging findings of 15 patients with post-COVID-19 rhino-orbito-cerebral mucormycosis who were diagnosed with invasive sinus mucormycosis at our institution and are currently undergoing treatment. All patients were diabetics, and 80% had a history of steroid intake during the course of COVID-19 treatment. There was a male preponderance (73.3%). The maxillary sinus was most commonly involved (86.7%). Orbital and intracranial invasion was seen in 73.3% and 60% of patients, respectively. The presence of retroantral, facial, infratemporal, and orbital fat stranding was an early sign of extrasinus spread. Other common sites of extrasinus involvement were the orbit and face, followed by the orbital apex, masticator space, pterygopalatine fossa, bone, skull base, cavernous sinus, brain, and internal carotid artery. In conclusion, early detection of extrasinus spread of mucormycosis by imaging is important so that aggressive treatment can be given and mortality can be reduced.

Keywords: COVID-19; extrasinus spread; mucormycosis.

Figure 1.

(a) Post-gadolinium T1-weighted image, with the right middle turbinate showing reduced enhancement, suggestive of the black turbinate sign (arrow). (b) T2-weighted axial image showing soft tissue in the medial extraconal space (arrow), with lateral displacement of the medial rectus. (c) T2-weighted coronal image depicting bulky left extraocular muscles with increased signal (star). Diffuse thickening of the left optic nerve sheath with a hyperintense signal in the left optic nerve suggests optic neuritis (arrow). (d) Post-gadolinium T1-weighted image showing a right inferior frontal gyrus abscess with thin peripheral enhancement (arrow). (e) Post-gadolinium T1-weighted image showing lack of contrast enhancement in the right internal carotid artery (arrow).