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Lateral occipital artery

The lateral occipital artery is a cortical branch of the posterior cerebral artery (PCA), typically arising from the calcarine or parieto-occipital branches. It primarily supplies the lateral and superior aspects of the occipital lobe, particularly areas involved in visual processing.

Function:

The lateral occipital artery plays a key role in vascular supply to the visual cortex, especially:

  • Lateral occipital gyri (visual association areas)

  • Parts of the primary visual cortex (V1) in some anatomical variants

  • Middle and inferior occipital gyri (sometimes overlapping with anterior temporal and angular areas)

MRI Appearance

T1-weighted images:

  • The lateral occipital artery appears as a small tubular low-to-intermediate signal structure along the posterior scalp and occipital musculature

  • Surrounded by high-signal fat, which enhances its visibility

  • Flow voids may be noted in larger branches on standard T1 sequences

T2-weighted images:

  • The artery demonstrates low signal intensity due to flowing blood, often appearing as hypointense tubular structures

  • Adjacent fat and muscle provide contrast for identification

  • Vascular pathology such as aneurysms, thrombosis, or arterial wall irregularity may appear as focal signal changes

STIR (Short Tau Inversion Recovery):

  • The vessel lumen remains low signal, while surrounding edema or inflammation in muscles or soft tissue appears hyperintense

  • Useful for detecting vascular compression, trauma-related hematoma, or adjacent soft tissue changes

T1 Post-Contrast (Gadolinium-enhanced):

  • The lateral occipital artery demonstrates homogeneous, tubular enhancement, clearly delineating its course

  • Highlights vascular branches, anastomoses, and pathological dilations

  • Essential for pre-surgical mapping, flap planning, and evaluation of vascular lesions

CT Appearance:

  • On conventional CT, the artery may be poorly visualized unless contrast is used

  • On CT angiography, it appears as a well-defined, contrast-enhanced tubular structure coursing over posterior muscles

  • Excellent for identifying arterial caliber, tortuosity, aneurysms, or trauma-related disruptions

MRI images

Lateral occipital artery mri sag image -img-00000-00000