【學術】Cerebral Venous Thrombosis

Introduction

• Cerebral venous thrombosis is located in descending order in the following venous structures:
• Major dural sinuses:
  Superior sagittal sinus, transverse, straight and sigmoid sinuses.
• Cortical veins:
  • Vein of Labbe, which drains the temporal lobe.
  • Vein of Trolard, which is the largest cortical vein that drains into the superior sagittal sinus.
• Deep veins: 
• Internal cerebral and thalamostriate veins.
• Cavernous sinus.

Clinical presentation

• Clinically patients with cerebral venous thrombosis present with variable symptoms ranging from headache to seizure and coma in severe cases.
• In adults, coagulopathies is the cause in 70% and infection is the cause in 10% of cases.
• In women, oral contraceptive use and pregnancy are strong risk factors.

Image

• Dense clot sign
• Direct visualization of a clot in the cerebral veins on a non enhanced CT scan is known as the dense clot sign. It is seen in only one third of cases.

• Empty delta sign
• The sign consists of a triangular area of enhancement with a relatively low-attenuating center, which is the thrombosed sinus. The likely explanation is enhancement of the rich dural venous collateral circulation surrounding the thrombosed sinus, producing the central region of low attenuation. 

• Absence of normal flow void on MR
• T2-weighted image with normal flow void in the right sigmoid sinus and jugular vein (blue arrow). On the left there is abnormal high signal as a result of thrombosis (red arrow).