Table 2.

Direct and indirect radiological signs providing value and certainty in the diagnosis of cerebral venous sinus thrombosis.

Test	Radiological sign
Head CT scan	Increased attenuation (hyperdensity) of the venous sinus or cortical vein (dense vein sign when superior longitudinal sinus is affected), especially when:
	Asymmetrical with regard to the contralateral side (in lateral sinus or cortical vein thrombosis)
	Decreased parenchymal attenuation (hypodensity) suggestive of venous infarction, especially if:
	Not corresponding to arterial territory
	Bilateral involvement
	Presence of subarachnoid or intraparenchymal component
	Signs of cerebral oedema:
	Decreased ventricular size
	Collapsed sulci
	Tortuosity of the optic nerve
	Flattening of the posterior sclera
	Optic disc protrusion
CT venography	Filling defect inside the affected venous sinus or cortical vein
Brain MRI	Iso- and hyperintensity in T1-weighted sequences and hypo-/hyperintensity in T2-weighted sequences of the venous sinus or cortical vein (acute/subacute phase)
	Cerebral oedema
	Hyperintensity in T2-weighted FLAIR sequences and diffusion in the affected venous sinus or cortical vein
Venous MRI angiography	Absence of flow in the venous sinus

CT: computed tomography; MRI: magnetic resonance imaging.

Techniques providing diagnostic certainty are shown in bold.