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Interpeduncular Cistern

The interpeduncular cistern is a cerebrospinal fluid (CSF)-filled subarachnoid cistern located at the base of the brain, specifically between the cerebral peduncles of the midbrain. It serves as a key anatomical space in the supratentorial compartment, lying below the floor of the third ventricle and above the pons. The cistern contains several crucial neural and vascular structures, making it significant in both normal neuroanatomy and in the context of various pathologies. Its visualization is important in neuroimaging for the assessment of conditions such as subarachnoid hemorrhage, aneurysms, and masses.

Synonyms

  • Basal cistern (when referring collectively to cisterns at the base of the brain)

  • Cistern of the interpeduncular fossa

  • Interpeduncular fossa cistern

Function

  • Acts as a reservoir for cerebrospinal fluid (CSF) circulation at the base of the brain.

  • Provides a cushioning effect for neurovascular structures traversing the base of the brain.

  • Contains important neurovascular structures:

    • Basilar artery bifurcation

    • Posterior cerebral arteries (initial segments)

    • Oculomotor nerves (cranial nerve III)

    • Perforating arteries to the midbrain

MRI Appearance

  • T1-weighted images:

    • The cistern appears as a well-defined, hypointense (dark) CSF-filled space between the cerebral peduncles.

    • Neurovascular structures (e.g., arteries, nerves) may be seen as small signal voids within the cistern.

  • T2-weighted images:

    • The interpeduncular cistern appears hyperintense (bright) due to the high water content of CSF.

    • Surrounding neural and vascular structures may appear as areas of low signal intensity within the bright CSF background.

  • FLAIR (Fluid-Attenuated Inversion Recovery):

    • The CSF signal is suppressed, so the cistern appears dark (hypointense).

    • Pathological processes (e.g., blood, pus, proteinaceous fluid) will appear hyperintense (bright) compared to normal CSF.

CT Appearance

  • Appears as a hypodense (dark) space between the cerebral peduncles, anterior to the midbrain.

  • Can be obscured or effaced in cases of mass effect, hemorrhage, or raised intracranial pressure.

  • Acute blood within the cistern (e.g., from subarachnoid hemorrhage) will appear hyperdense (bright) compared to the normal hypodense appearance of CSF.

MRI images

Interpeduncular cistern mri 3t sagittal image

CT image

Interpeduncular Cistern CT sag anatomy image -img-00001-00001