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Vestibular ganglion

The vestibular ganglion, also known as Scarpa’s ganglion, is a collection of bipolar sensory nerve cell bodies located in the internal auditory canal, associated with the vestibular nerve, which is a division of the vestibulocochlear nerve (cranial nerve VIII). This ganglion plays a critical role in transmitting sensory information related to balance from the semicircular canals, utricle, and saccule of the inner ear to the brainstem. Due to its location and function, the vestibular ganglion is an important structure in neuro-otology and radiology, particularly in the assessment of vestibular nerve disorders.

Synonyms:

  • Scarpa’s ganglion

  • Vestibular nerve ganglion

  • Ganglion of the vestibular nerve

Function:

  • Contains bipolar sensory neuron cell bodies.

  • Transmits balance and spatial orientation information from the peripheral vestibular apparatus (utricle, saccule, and semicircular canals) to the vestibular nuclei in the brainstem.

  • Plays a key role in maintaining balance and equilibrium.

  • Essential for the vestibulo-ocular reflex (stabilizing gaze during head movement).

MRI Appearance:

  • 3D T2-Weighted MRI:

    • The vestibular ganglion appears as a small, well-defined, ovoid structure within the fundus of the internal auditory canal (IAC), anterior and superior to the cochlear nerve.

    • Intermediate to mildly hyperintense signal relative to surrounding cranial nerves.

    • Fine-resolution 3D T2 sequences (e.g., CISS, FIESTA, or SPACE) are optimal for visualizing its borders.

  • T1-Weighted MRI:

    • The vestibular ganglion is typically isointense to surrounding nerve tissue.

    • May be difficult to differentiate from the rest of the vestibulocochlear nerve without contrast.

    • Gadolinium enhancement is not typical unless there is pathology (e.g., inflammation, tumor).

CT Appearance:

  • The vestibular ganglion itself is not directly visualized on standard CT due to its small size and similar density to adjacent neural tissue.

  • CT can show the bony anatomy of the internal auditory canal and can be useful for assessing canal widening, erosions, or bone lesions affecting the region where the vestibular ganglion resides.

  • Indirect signs (e.g., expansion or bony changes in the fundus of the IAC) may suggest pathology involving the ganglion.

MRI images

Vestibular ganglion MRI 3T axial image 1

MRI images

Vestibular ganglion MRI 3T axial image

MRI images

Vestibular ganglion MRI 3T sagittall image