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

  • Can look bizarre, mimic neoplasm

TERMINOLOGY

IMAGING