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Topic

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Internal carotid artery (cavernous part)

The cavernous part of the internal carotid artery (ICA), also known as the cavernous segment, is a critical vascular structure located within the cavernous sinus at the base of the skull. It follows a tortuous “S-shaped” course, known as the carotid siphon, as it passes through the cavernous sinus, surrounded by important cranial nerves and venous channels. The cavernous segment provides vital blood supply to the brain, the pituitary gland, and adjacent structures. Its unique anatomical location makes it significant in neurovascular, endovascular, and surgical procedures, as well as in various pathological conditions such as aneurysms, fistulas, and tumors.

Synonyms

  • Cavernous segment of the internal carotid artery

  • Cavernous ICA

  • Carotid siphon (includes both cavernous and supraclinoid parts)

  • Pars cavernosa arteriae carotidis internae

Function

  • Supplies arterial blood to the brain, specifically parts of the pituitary gland, optic chiasm, and the cavernous sinus region

  • Provides branches such as the meningohypophyseal trunk and inferolateral trunk

  • Plays a role in collateral circulation via anastomoses with external carotid artery branches

MRI Appearance

  • T1-Weighted Images:

    • The cavernous ICA appears as a flow void (black signal) due to rapid blood flow

    • Surrounding cavernous sinus shows intermediate signal intensity

  • T2-Weighted Images:

    • ICA is again seen as a flow void (dark signal)

    • The cavernous sinus may appear hyperintense due to slow-flowing venous blood

  • STIR (Short Tau Inversion Recovery):

    • ICA remains a flow void

    • Adjacent soft tissues and pathological processes (e.g., inflammation or tumors) appear hyperintense

  • TOF (Time-of-Flight) MR Angiography:

    • ICA demonstrates high signal (bright appearance) due to the inflow of unsaturated blood

    • Clearly delineates the tortuous course within the cavernous sinus

    • Useful for detecting aneurysms, stenosis, or vascular malformations

CT Appearance

  • On non-contrast CT, the cavernous ICA is not distinctly visualized except as a round/oval low-attenuation area within the cavernous sinus

  • Surrounding bone structures (sphenoid, carotid canal) provide anatomical landmarks

  • Hyperdense vessel sign may be seen in acute thrombosis

CTA (CT Angiography) Appearance

  • Cavernous ICA is clearly visualized as a well-defined contrast-filled vessel following an S-shaped course within the cavernous sinus

MRI images

Internal carotid artery (cavernous part) coronal image

MRI images

Internal carotid artery (cavernous part) mri axial image