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Dural Sinus Thrombosis

KEY FACTS

IMAGING

• General features

○ Empty-delta sign on CECT, T1WI C+ MR

• CT

○ Hyperdense sinus on NECT (usually > 70 Hounsfield

units)

○ ± hyperdense cortical veins (cord sign)

○ CTV: Filling defect (thrombus) in dural sinus

• MR

○ Hypointense thrombus "blooms" on T2* GRE

○ Absence of flow in occluded sinus on 2D TOF MRV

• Protocol recommendations

○ NECT, CECT scans ± CTV as initial screening

○ If CTs negative, MR + MRV (T2*, DWI, T1WI C+)

○ If MRV equivocal, DSA is gold standard

TOP DIFFERENTIAL DIAGNOSES

• Normal (arteries, veins normally slightly hyperdense)

• High hematocrit (newborns, polycythemia)

• Dural sinus hypoplasia/aplasia: No "blooming";

collaterals/venous infarcts absent

• "Giant" arachnoid granulations: Round/ovoid, not

elongated like thrombus

• Acute subdural hematoma: Blood layered on tentorium can

mimic transverse sinus (TS) thrombosis

CLINICAL ISSUES

• May present with headache and papilledema

DIAGNOSTIC CHECKLIST

• Review MRV source images; exclude pseudocollusions (e.g.,

hypoplastic TS)

• Review T1 images to exclude false-negative MRV

• Review NECT to exclude dense thrombus as false-negative

CECT or CTV

• Brain looks normal; does not exclude CVT

• DSA helpful if noninvasive imaging inconclusive

• Chronic thrombosis may enhance; recanalization or

granulation tissue enhances

(Left) Sagittal graphic shows

thrombosis of the superior

sagittal sinus ſt and straight

sinus ﬇. Inset in the upper

left reveals a thrombus in the

superior sagittal sinus in cross

section (empty = delta sign) st

seen on contrast-enhanced

imaging. (Right) NECT scan in

a 25-year-old man with

progressively increasing

headaches shows hyperdensity

in the right transverse ſt and

straight sinuses st. Both

internal cerebral veins are

hyperdense ﬇, and the right

thalamus ﬊ is hypodense and

edematous.

(Left) Axial source image from

a CTV in the same patient

shows that the dura around

the superior axial sinus

enhances ſt, but its clot-filled

lumen ﬇ does not (emptydelta sign). (Right) Sagittal

reformatted view of the CTV

in the same patient shows

extensive nonenhancing

thrombus in the superior

sagittal ﬊ and straight ſt

sinuses. The internal cerebral

veins ﬇ are occluded and do

not enhance. Findings indicate

extensive dural sinus, deep

vein thrombosis.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

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