Hyperdense Dural Sinus

Anne G. Osborn, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Physiologic Hyperdensity
Thrombosis, Dural Sinus
Polycythemia
Subdural Hematoma, Acute (Mimic)

Less Common

Lymphoma, Metastatic, Intracranial
Metastases, Skull and Meningeal
Meningioma

Rare but Important

Hemangioma
Leukemia
Extramedullary Hematopoiesis (Mimic)
Masson Hemangioma

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Evaluate density, configuration of dural sinuses
- ALL dural sinuses appear slightly hyperdense compared to adjacent brain, CSF on NECT
- Margins of dural sinuses typically flat or slightly concave
Density: Is “dense dural sinus” TOO dense?
- Measure dural sinus density
- Compare to internal carotid artery (as internal standard)
- If too dense, is it thrombosis or polycythemia?
  - Dural sinus thrombosis (DST) > > polycythemia
  - Check hematocrit!
  - If any question, do CECT + CTV or MR + MRV (include GRE or SWI sequence!)
  - Look for nonenhancing thrombus
Configuration: Disrupted dural sinus, bulging dural sinus, irregular/lobulated dural sinus
- Some neoplasms invade dural sinuses
- Usually meningioma or metastasis
- May appear hyperattenuating if densely cellular
- May also cause dural sinus thrombosis (e.g., meningioma in superior sagittal sinus)

Helpful Clues for Common Diagnoses

Physiologic Hyperdensity
- At hematocrit of 43 (normal)
  - Intravascular blood in arteries, veins, dural sinuses appears slightly hyperdense compared to normal brain
  - At hematocrit of 70, circulating blood 63% denser
- Dural sinuses appear especially dense in newborns because of
  - Physiologic polycythemia at birth
  - Unmyelinated/low density brain
Thrombosis, Dural Sinus
- Many causes of DST
- Trauma
  - May tear sinus
  - ± Thrombosis
  - Thin subdural hematoma can layer along falx, tentorium, mimic “empty delta sign” (latter seen on CECT, not NECT!)
- Meningitis
- Dehydration, hypovolemia
  - Shock, cardiac failure, other “low flow” states
- Hypercoagulable states
  - Antiphospholipid antibody syndrome
  - Von Willebrand disease
  - Post-anticoagulation “rebound” phenomenon
  - Postpartum
- Hormonal
  - Pregnancy, postpartum
  - Oral contraceptives
- Hemoglobinopathies (e.g., sickle cell disease, thalassemia)
- Vasculitis
  - Some vasculitides (e.g., Behçet) have propensity to cause DST
Polycythemia
- Can be physiologic
  - Newborn
  - High altitude
- Pathologic
  - Cyanotic congenital heart disease
  - COPD
- ALL vessels (arteries, veins, dural sinuses) become hyperdense in polycythemia
  - ↑ Hemoglobin protein → ↑ dural sinus density
  - NECT in patient with polycythemia “looks like” a CECT
  - Do not mistake for DST (MR + MRV clarifies)
Subdural Hematoma, Acute (Mimic)
- May layer along tentorium, superior sagittal sinus → mimic dural thrombosis

Helpful Clues for Less Common Diagnoses

Lymphoma, Metastatic, Intracranial
- Central skull base lymphoma may extend diffusely
  - Destroys bone
  - Infiltrates adjacent structures
  - May extend into one or both cavernous sinuses
- Hyperdense, strongly enhancing
Metastases, Skull and Meningeal
- Skull metastases commonly invade underlying dura
- If adjacent to dural venous sinus, may extend into and compromise sinus
Meningioma
- Expands into (or, less commonly, originates from) dural venous sinus
- Grows slowly, so collateral blood flow develops
- Sellar/parasellar/clival meningiomas commonly involve one or both cavernous sinuses

Helpful Clues for Rare Diagnoses

Hemangioma
- Capillary &/or cavernous hemangiomas may arise within dura
- Cavernous sinus common site
- May mimic meningioma
Leukemia
- Dural-based mass(es) along falx can mimic DST
- Adjacent to, usually not within, venous sinus
Extramedullary Hematopoiesis (Mimic)
- Dural-based mass(es) typical adjacent to, not within, venous sinus
Masson Hemangioma
- Synonyms
  - Vegetant intravascular hemangioendothelioma
  - Intravascular papillary endothelial hyperplasia (IPEH)
- Found in head, neck, fingers, trunk, occasionally viscera (liver)
- Exuberant endothelial proliferation within veins, including dural venous sinus
- Benign; can be mistaken for angiosarcoma