Table 3.

Key Imaging Findings to be Assessed and Documented

Stage 1: Look for specific signs of invasive sinusitis apart from nonspecific mucosal thickening or collection such as

Periantral loss of fat planes or stranding

Lack of sinus mucosal enhancement (LOE)

Lack of turbinate enhancement (black turbinate)

Involvement of nasal septum/palate (perforation and LOE)

Look for pterygopalatine fossa (PPF) involvement

Bony erosions (CT)

Stage 2: Look for specific signs of invasive sinusitis extending to orbits such as

Orbital fat stranding (dirty fat sign on T2-FS)

Look for features of early involvement of medial orbital wall and extraocular muscles

In case of vision loss, look for optic nerve ischemic infarct (DWI-restricted diffusion)

Look for Involvement of orbital apex and fissures

Look for perioptic sheath, sclera and globe morphology

Look for loss of flow void &and enhancement in the superior ophthalmic vein (If enlarged, then rule out cavernous sinus thrombosis)

Bony erosions (CT)

Stage 3: Look for specific signs of invasive sinusitis extending to CNS such as

Cavernous sinus and Meckel’s cave involvement (enlargement and LOE)

Look for signs of carotid artery narrowing or thrombosis or pseudoaneurysm formation

Look for features of cranial nerve thickening especially, trigeminal nerve

Look for meningeal thickening and enhancement in ACF and MCF

Look for skull base involvement in T2-FS and PC-T1FS thin sections

Look for cerebritis or abscess or infarcts or subarachnoid hemorrhage

Bony erosions (CT)

CT, computed tomography; T2-FS, T2-weighted fat-suppressed; DWI, diffusion-weighted imaging; CNS, central nervous system; ACF, anterior cranial fossa; MCF, middle cranial fossa; PC-T1FS, postcontrast T1-weighted fat-saturated images.