Sinus thrombosis

NECT:
Dense Delta sign = dense clot sign - commonly seen in SSS, can be seen in other sinuses too.
Non-arterial infarcts
Dense cortical veins = cord sign
Often a/w hemorrhage
Infarction of basal ganglia and thalami is typical of CVT (this is not a feature of arterial infarct)
Temporal lobe infarct - vein of Labbe thrombosis
Pitfalls:
Hyperdense sign can be normal in infants and neonates, in patients with increased hematocrit (dehydration, polycythemia)
Subdural hemorrhage can mimic CVT and vice versa

CECT:
Empty delta sign, commonly seen in SSS, can be seen in other sinuses too.
Enhancement of falx and tent
Pitfalls:
Intrasinus septa can mimic empty delta sign

MR:
GE images for hemorrhage
Acute: iso on T1, low on T2
Subacute: high on T1 and T2
Chronic: iso on T1 and T2
TOF - short imaging time, beware of artefacts, more false positives, false negative due to methHb
Phase contrast - artefacts due to movements and turbulent flow, no false negative due to methHb
Post-Gd venogram - less false positives, false negative due to methHb or enhancing chronic thrombus
Pitfalls:
Intrasinus septa can mimic CVT
Slow flow may mimic loss of flow void
MethHb may show increased signal on TOF

References:
Poon CS et al. Radiologic Diagnosis of Cerebral Venous Thrombosis. AJR 2007; 189:S76-S78