Dural venous sinus thrombosis for Radiology & Imaging

Dural venous sinus thrombosis for Radiology & Imaging

1. Dural Venous Sinus Thrombosis Dr. Manmohan Bir Shrestha FOR RADIOLOGY

2. Dural venous sinuses are venous channels located intracranially between the two layers of dura mater. run alone, not parallel to arteries are valveless, allowing for bidirectional blood flow in intracranial veins it is also important to note that the draining territories of intracranial veins are different from those of major cerebral arteries.  form the major drainage pathways from the brain, predominantly to the internal jugular veins.

3. Can be classified as - Paired Transverse sinus Sigmoid sinus Superior petrosal sinus Inferiror petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus Unpaired Superior sagittal sinus inferior sagittal sinus Straight sinus Occipital sinus Intercavernous sinus

4. Venous angle & Internal Cerebral veins Septal vein – runs on the medial surface of frontal horn Thalamostriate vein – runs in the floor of the lateral ventricle Venous angle In the lateral view, the junction of septal & thalamostriate vein forms the origin of internal cerebral vein & is known as the “Venous Angle” Internal cerebral vein commence just behind the foramen of monro Near the splenium, 2 internal cerebral vein unites & continues as great cerebral vein of Galen

5. Venous Angle

6. Basal/Rosenthal Vein Deep middle cerebral vein drains the insula & is joined by anterior cerebral & striate veins to form the basal vein Basal vein arises anteriorly above the sella & passes around the midbrain to enter the back end of the Internal Cerebral Vein

7. Straight Sinus Vein of Galen curves upward & backward behind the splenium of the corpus callosum Here, it joins inferior sagittal sinus to form the straight sinus which passes downward in the apex of the tentorium to the torcular herophili Straight sinus usually drains into the left transverse sinus Superior sagittal sinus usually drains into the right transverse sinus

8. The vein of Trolard & Labbe The vein of Trolard/ Superior anastomotic vein Large vein which passes upward & backward over the cerebral hemisphere to enter the superior sagittal sinus in the parietal region. Connects superficial middle cerebral vein to superior sagittal sinus The vein of Labbe/ Inferior anastomotic vein Large vein which passes horizontally across the temporal region to enter the transverse sinus. Connects superficial middle cerebral vein to transverse sinus T – Trolard – Top one L- Labbe – Lower one

9. Torcular Herophili / Torcula The  confluence of sinuses Superior sagittal sinus Straight sinus Occipital sinus Transverse sinuses The anatomy is highly variable type 1 : superior sagittal sinus drains into one lateral sinus and the straight sinus into the other, with no connection between the two type 2 : superior sagittal sinuses and the straight sinus fork, and the forks from both sinuses join to form the lateral sinuses type 3 : a true confluence of sinuses

10. Cavernous sinus Located on either side of pituitary fossa & body of the sphenoid bone It spans from the apex of the orbit to the apex of the petrous temporal bone Structures passing through are – Internal Carotid Artery Oculomotor nerve Trochlear nerve Abducens nerve Ophthalmic nerve Maxillary nerve

11. Cavernous sinus Receives blood from Superior & inferior ophthalmic vein Intercavernous sinus Sphenoparietal sinus Superficial middle cerebral vein Occasionally central retinal vein Drains into Superior petrosal sinus Inferior petrosal sinus Basilar venous plexus

12. Dural Venous Sinus Thrombosis

13. Dural Venous Sinus Thrombosis Thrombotic occlusion of dural venous sinuses Often coexist with cortical vein thrombosis Can occur in isolation of single venous sinus or in combined with one another Common occurrence- Superior sagittal sinus Straight sinus Transverse sinus Sigmoid sinus Cavernous sinus

14. Age Any age Gender Female>Male

15. Predisposing factors Identified in most cases Hormonal Oral contraceptive pill Pregnancy, puerperium, steroids Hematological - coagulopathy Genetics – Protein S deficiency Prothrombin gene mutation Resistance to activated protein C

16. cont....... Local factors Skull trauma Compressing mass Infection – specially mastoid sinus Systemic illness Dehydration Sepsis Malignancy Connective tissue disorders idiopathic

17. Clinical features Headache Nausea Vomiting Seizures Altered consciousness Altered vision Cavernous sinus thrombosis can result in Exophthalmos Chemosis ( swelling of conjunctiva) Oedema of the eyelids Oculomotor palsies. Papilloedema.

18. Pathology Thrombus in dural venous sinus Clot propagates into cortical veins Venous drainage obstructed, venous pressure elevated Blood-brain barrier breakdown with vasogenic edema, hemorrhage Venous infarct with cytotoxic edema

19. Imaging modalities NECT CECT CT Venogram MRI MR Venogram

20. NECT Findings can be subtle when no venous hemorrhage or infarct Cerebral edema Venous hemorrhage Venous infarct Hyperdense vein sign >65 HU Compare to carotid arteries

21. Cont … Cord sign Cordlike hyper attenuation within a dural venous sinus A false positive cord sign may also be seen in the setting of generalized cerebral edema when it is actually the brain which is of reduced density rather than the sinus being hyperdense.   

22. Cord sign

23. CECT & CT Venogram Filling defect in dural sinus Shaggy enlarged/irregular collateral venous channels Empty delta sign Enhancing dura surrounds non-enhancing thrombus In coronal/axial section in superior sagittal sinus

24. Empty delta sign Delta  (uppercase  Δ , lowercase  δ) Is the 4 th letter of Greek word Delta sign resembles a triangle

25. MRI T1WI Acute thrombus – isointense with brain Subacute thrombus – hyperintense Chronic thrombus - isointense T2WI Acute thrombus –hypointense ( can mimic normal flow void) Subacute thrombus – hyperintense Chronic thrombus – hyperintense T2*GRE Hypointense thrombus usually blooms

26. 2D TOF or Contrast MRV Absence of flow in occluded sinus in 2D TOF MRV Contrast enhanced MRV shows thrombus & collaterals much better Flow gaps on MIPs must be reviewed on source images to exclude hypoplastic sinus variants, particularly for transverse & sigmoid sinus

27. Case of – young adult female with sudden onset severe headache and left sided weakness Cases

28. After 9 hours Right sided venous hemorrhage with multilobulated appearance

29. Case of 30 yrs. old female. Postpartum severe headache and disturbed conscious level.

30. SWI

31. Treatment In-patient heparin followed by out-patient warfarin Anticoagulation is usually required even in the setting of venous hemorrhage. Interventional management includes microcatheter thrombolysis or thromboplasty *** Associated abnormalities – Dural AV fistula

32. Differential diagnosis Dural sinus hypoplasia-aplasia 31% flow gaps in nondominant sinus Right transverse sinus dominant – 59 % Left transverse sinus dominant – 25% Concomitant – 16 % If the sinus is small or absent, then the ipsilateral sigmoid sinus and jugular fossa should also be small

33. Giant arachnoid granulations Round/ovoid filling defect CSF signal density/signal intensity By imaging – most common location is transverse sinus On histopathology – superior sagittal sinus is most common location

34. Presenting case