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Topic

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Transverse sinus

The transverse sinus is a paired dural venous sinus located within the posterior aspect of the cranial cavity. It runs laterally from the confluence of sinuses, curving along the occipital bone’s attached margin of the tentorium cerebelli, and then transitions into the sigmoid sinus at the petrous temporal bone. The transverse sinus is a crucial component of the cerebral venous system, draining blood from the brain and directing it toward the internal jugular vein.

Synonyms

  • Lateral sinus (older term, less used in modern radiology)

  • Sinus transversus (Latin)

Function

  • Drains venous blood from the superior sagittal sinus and straight sinus via the confluence of sinuses

  • Receives blood from the superior petrosal sinus, inferior cerebral veins, inferior cerebellar veins, and diploic veins

  • Channels deoxygenated blood into the sigmoid sinus, which then drains into the internal jugular vein

  • Facilitates cerebrospinal fluid (CSF) absorption by draining CSF-containing blood from the arachnoid granulations

MRI Appearance

T2-weighted (T2):

  • Normal: Flow void – the transverse sinus appears as a dark/black signal due to rapid blood flow

  • If thrombosed: Loss of flow void; may appear hyperintense (bright) in subacute thrombosis

T1-weighted (T1):

  • Normal: Low to intermediate signal intensity (similar to other venous sinuses, typically dark/grey)

  • If thrombosed: Variable; hyperintense in subacute phase (due to methemoglobin), iso- to hypointense in acute/chronic phases

3D Phase Contrast (PC) MR Venography:

  • Normal: Demonstrates patent flow as high signal within the sinus

  • Absent or reduced signal indicates stenosis or occlusion (e.g., thrombosis)

Post-Contrast T1 (Gadolinium-enhanced):

  • Normal: Homogeneous enhancement of the sinus wall and lumen, showing bright linear structure

  • Filling defects (non-enhancing areas) may indicate thrombus or intraluminal pathology

CT Appearance

Non-contrast CT:

  • Normal: Transverse sinus may be difficult to distinguish; typically seen as a hypoattenuating (dark) area, sometimes with a thin hyperdense wall

  • Hyperdense transverse sinus sign may indicate acute thrombosis (increased attenuation of blood)

CT Venography (CTV):

  • Normal: Well-opacified, symmetric linear or tubular filling of the transverse sinus

  • Thrombosis: Filling defects, absence of opacification, or “empty delta sign” (for superior sagittal sinus but can also help identify other dural sinus thromboses), and possible sinus expansion

MRI images

Transverse sinus MRI 3T axial image

MRI images

Transverse sinus MRI 3T coronal image

MRI images

Transverse sinus MRI 3T sagittal image