Fungal sinusitis

Acute invasive:
Rapidly progressing infection
Seen commonly in immunocompromised patients, diabetec ketoacidosis
Mortality of 50%–80%
Primary site is nasal cavity with common involvement of middle turbinate
CT:
Mucosal thickening of paranasal sinus and nasal cavity
Complete opacification with expansion, erosion, remodelling, thinning
Calcification (70%) - primarily central (non fungal - peripheral), fine punctate (non fungal - eggshell, round)
More often unilateral with involvement of ethmoid and sphenoid sinuses
Bone destruction
Cavernous sinus thrombosis, or carotid artery invasion, occlusion or pseudoaneurysm may be seen
MR:
Low T2 signal
Orbital extension - inflammatory changes in periorbital fat, proptosis
Obliteration of periantral fat
Leptomengeal enhancement

Chronic invasive:
Usually immuno competent
CT:
Masslike soft tissue with destruction of sinus walls and extension beyond the sinus
May be bony sclerosis
MR:
Low on T1 and very low on T2-weighted

Allergic fungal sinusitis:
Young people
CT:
Opacification and expansion
MR:
Low or hig signal on T1, low signal on T2

Fungal ball:
Mass within sinus, common in maxillary sinus
CT:
High density
May be punctate calcifications
MR:
Low on T1 and T2

References:
1. Aribandi M et al. Imaging Features of Invasive and Noninvasive Fungal Sinusitis: A Review. RadioGraphics 2007;27:1283-1296