Topics

Topic

design image
Lateral mesencephalic vein

The lateral mesencephalic vein is a key cerebral vein located along the lateral aspect of the midbrain (mesencephalon). It is an important component of the deep venous drainage system of the brainstem, providing venous return from the lateral midbrain and adjacent structures. The vein is frequently visualized in advanced neuroimaging studies and holds clinical significance due to its anatomical location and potential involvement in pathological processes. Understanding its imaging characteristics and anatomical variations is essential for radiologists and neurosurgeons.

Synonyms

  • Lateral midbrain vein

  • Vena mesencephalica lateralis (Latin)

  • Lateral vein of the mesencephalon

Function

  • Drains venous blood from the lateral aspect of the midbrain

  • Receives tributaries from the cerebral peduncle, tectum, and surrounding tegmental regions

  • Empties typically into the basal vein of Rosenthal or the superior petrosal sinus

  • Plays a role in maintaining venous outflow from critical midbrain structures

MRI Appearance

  • T2-Weighted Imaging:

    • Appears as a linear, hypointense (dark) structure due to flow void; typically runs parallel to the lateral surface of the midbrain

  • T1-Weighted Imaging:

    • Generally appears as a linear, hypointense signal (flow void); rarely visualized unless thrombosed or slow flow

  • Phase Contrast 3D (PC 3D) MRI:

    • Enhances visualization of small veins; the lateral mesencephalic vein is typically well delineated as a thin, curvilinear flow signal lateral to the midbrain

  • Post-Contrast T1-Weighted Imaging:

    • Shows thin, linear enhancement along the lateral surface of the midbrain, consistent with venous enhancement

    • Enhancement may be more prominent if the vein is dilated or if there is slow flow

CT and CTV (CT Venography) Appearance

  • Non-Contrast CT:

    • Usually not visualized due to its small size and lack of inherent contrast from surrounding brain tissue

  • CT Venography (CTV):

    • Can be seen as a thin, linear enhancing structure along the lateral margin of the midbrain

    • Best visualized with thin-section, high-resolution imaging and appropriate venous phase timing

    • May be more apparent in cases of venous congestion or anatomical variation

MRI images

Lateral mesencephalic vein MRI 3T axial image