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Superior sagittal sinus

The superior sagittal sinus is a large, unpaired dural venous sinus located along the midline of the brain. Running within the superior margin of the falx cerebri, it serves as a major channel for venous blood drainage from the cerebral hemispheres. This sinus extends from the foramen cecum at the frontal bone anteriorly to the confluence of sinuses at the internal occipital protuberance posteriorly. The superior sagittal sinus plays a crucial role in draining cerebrospinal fluid (CSF) via arachnoid granulations and directs blood towards the transverse sinuses.

Synonyms

  • Superior longitudinal sinus

  • Sinus sagittalis superior

  • Sagittal sinus

Function

  • Major venous drainage channel for the cerebral hemispheres

  • Receives blood from superior cerebral veins

  • Drains cerebrospinal fluid (CSF) through arachnoid granulations

  • Directs venous blood flow posteriorly towards the confluence of sinuses

  • Regulates intracranial pressure by facilitating CSF resorption

MRI Appearance

  • T2-Weighted MRI:

    • Appears as a flow void (dark signal) due to rapid blood flow

    • Lined by hyperintense dura mater

    • Thrombus or slow flow may appear hyperintense

  • T1-Weighted MRI:

    • Normally appears hypointense (dark) due to flowing blood

    • Acute thrombus may appear isointense to mildly hyperintense

    • Dura appears as a thin low-signal rim

  • Phase-Contrast 3D (PC 3D):

    • Demonstrates high signal intensity within the sinus

    • Clearly delineates venous flow and sinus patency

    • Useful in assessing flow abnormalities, stenosis, or thrombosis

  • Post-Contrast T1-Weighted MRI:

    • Strong enhancement of the sinus lumen

    • Clearly outlines the sinus margins

    • Absence of enhancement suggests thrombosis or occlusion

    • Helps differentiate sinus from adjacent dura or brain tissue

CT Appearance

  • Non-contrast CT:

    • Appears as a linear or triangular hypodense structure along the midline

    • Acute thrombosis may be hyperdense (dense triangle sign)

    • Normal sinus not easily distinguished without contrast

  • CT Venography (CTV):

    • Superior sagittal sinus is well-opacified with contrast

    • Appears as a bright linear or triangular structure along the midline

    • Filling defects indicate possible thrombus or flow disturbance

    • Provides clear visualization of sinus patency and anatomy

MRI images

Superior sagittal sinus MRI 3T sagittal image

MRI images

Superior sagittal sinus MRI 3T sagittal MIP PC 3D image

CT image

Superior sagittal sinus CT IMAGE