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Superior petrosal sinus

The superior petrosal sinus is a short but critical dural venous sinus located in the posterior cranial fossa. Running along the superior margin of the petrous part of the temporal bone, it connects the cavernous sinus anteriorly to the transverse sinus posteriorly. It plays an important role in draining blood from the cavernous sinus and cerebellar veins into the transverse sinus, and is frequently encountered in neuroimaging, especially in pre-surgical planning and in the evaluation of venous pathologies.

Synonyms

  • SPS

  • Sinus petrosus superior

  • Superior petrosal dural sinus

Function

  • Serves as a venous conduit between the cavernous sinus and transverse sinus.

  • Drains blood from the cerebellar veins, brainstem veins, and some petrosal veins.

  • Contributes to the venous outflow of the posterior fossa.

MRI Appearance

  • T2-weighted Imaging

    • Appears as a flow void (signal loss), showing as a dark linear or tubular structure along the petrous ridge.

    • When slow flow or thrombosis is present, may show increased signal.

  • T1-weighted Imaging (Non-Contrast)

    • Typically seen as a flow void (low signal) similar to other dural sinuses.

    • Difficult to distinguish if not specifically sought.

  • Phase Contrast 3D MR Venography (PC 3D)

    • Demonstrates the superior petrosal sinus as a small, enhancing venous structure, best visualized in thin-slice, high-resolution reconstructions.

    • Useful for delineating venous anatomy and detecting flow-related abnormalities.

  • Post-Contrast T1-weighted Imaging

    • Shows linear or tubular enhancement along the superior margin of the petrous temporal bone.

    • Enhancing signal confirms patency and assists in evaluation for thrombosis or anatomic variants.

CT Appearance

  • Non-contrast CT

    • May show as a faint groove or channel along the superior margin of the petrous bone.

    • Venous sinus itself usually not distinctly visualized unless there is calcification or adjacent pathology.

  • CT Venography (CTV)

    • Superior petrosal sinus is depicted as an enhancing venous channel, best seen on thin-section multiplanar reconstructions.

    • Assists in assessment of patency, variations, or thrombosis.

MRI images

Superior petrosal sinus MI 3T axial image

MRI images

Superior petrosal sinus MI 3T coronal image

MRI images

Superior petrosal sinus MI 3T sagittal image