Cavernous Sinus Thrombosis/Thrombophlebitis

KEY FACTS

IMAGING

• CT

○ Bone CT

– Look for sinus infection, erosive changes

○ CECT

– Nonenhancing filling defects (clot) inside enhancing

dural walls of cavernous sinus (CS)

– CS margins convex (not flat/concave)

○ CTA/CTV

– Filling defects in 1 or both CSs

• MR

○ T1WI

– Convex, enlarged CS (isointense to gray matter)

– Orbits: ± "dirty fat," enlarged EOMs, proptosis

○ T2WI

– Clot heterogeneously hypointense

– Look for absent carotid "flow void"

○ T2*: Thrombus "blooms"

○ T1 C+: Dura enhances; clot doesn't

– Clot heterogeneous; ± absent carotid "flow void"

TOP DIFFERENTIAL DIAGNOSES

• Neoplasm (meningioma, schwannoma, lymphoma)

• Carotid-cavernous fistula

• Inflammatory pseudotumor (IgG4-related disease, sarcoid)

CLINICAL ISSUES

• Headache early

• Orbital/sinus pain, edema, chemosis

• Ptosis, ophthalmoplegia, visual loss

• Cranial neuropathy (typically V1 &/or V2)

• Prognosis

○ Spreads via communicating veins to contralateral CS, eye

○ Untreated CS thrombophlebitis can be fatal

DIAGNOSTIC CHECKLIST

• If initial CT negative and clinical suspicion high, CTA/CTV or

MR/MRV

(Left) Clinical photograph in a

patient with septic cavernous

sinus thrombosis shows ptosis

of right eyelid ſt and

chemosis ﬇. (Right) Axial

CECT in a 16-year-old boy with

severe sphenoid sinusitis st

shows bilateral "filling

defects" (nonenhancing clots

﬇) within the enhancing dura

ſt of the cavernous sinus. The

left superior ophthalmic vein is

also thrombosed ﬊.

(Left) Axial T1 C+ FS in the

same case shows the

nonenhancing thrombus ﬇

within the intensely enhancing

walls of the cavernous sinus

ſt. (Right) Coronal T2WI in

the same case shows sphenoid

sinusitis st, heterogeneously

hypointense thrombus ﬇

bulging the cavernous sinus

walls laterally ſt.

Trauma, and Stroke

Brain: Pathology-Based Diagnoses: Malformations,

105