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Petrosal vein

The petrosal vein is a significant cerebral vein that drains blood from the brainstem and cerebellum into the dural venous sinuses, notably the superior and inferior petrosal sinuses. It plays a key role in the venous drainage of the posterior fossa structures. Recognizing the petrosal vein and its variants on neuroimaging is essential for accurate diagnosis and surgical planning, especially in posterior fossa pathologies.

Synonyms

  • Superior petrosal vein (SPV)

  • Inferior petrosal vein (IPV)

  • Petrosal bridging vein

  • Pontotrigeminal vein

  • Lateral mesencephalic vein (sometimes considered a tributary)

  • Transverse pontine vein (related, may be a synonym in some texts)

Function

  • Drains venous blood from the cerebellum, brainstem, and petrosal region

  • Empties primarily into the superior petrosal sinus (superior petrosal vein) or the inferior petrosal sinus (inferior petrosal vein)

  • Provides critical venous outflow for posterior fossa and adjacent neural structures

MRI Appearance

  • T2-Weighted Imaging

    • Appears as a linear or curvilinear structure with flow void (signal loss) in the petrosal region

    • May be challenging to visualize if small or slow-flowing

  • T1-Weighted Imaging

    • Visualized as a hypointense (dark) tubular structure

    • Non-contrast images often show it as a flow void (signal loss)

  • 3D Phase Contrast (PC) MRI

    • Clearly delineates venous structures based on flow

    • Petrosal veins appear as well-defined, enhancing tubular structures in the petrosal region

    • Useful for evaluating the venous anatomy in relation to cranial nerves and vascular lesions

  • Post-Contrast T1-Weighted Imaging

    • The petrosal vein enhances and becomes hyperintense (bright)

    • Best visualized after administration of gadolinium contrast

    • Facilitates identification of venous anatomy, patency, and thrombosis

CT and CTV Appearance

  • Non-contrast CT

    • Petrosal veins are generally not visualized unless thrombosed or calcified

    • Subtle linear hypodense (dark) structures in the petrosal region may be noted in rare cases

  • CT Venography (CTV)

    • Enhances the petrosal veins as hyperdense (bright) tubular structures

MRI images

Petrosal vein MRI 3T axial image

MRI images

Petrosal vein MRI 3T coronal image

MRI images

Petrosal vein MRI 3T sagittal image