Spoke wheel sign (meningioma)

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The spoke wheel sign refers to the pattern of vessels coursing through meningiomas, when seen in cross-section.  It is the result of the same phenomenon which results in the sunburst pattern (vessels seen from the side rather than in cross-section).

Terminology

A similar appearance also referred to as a spoke wheel sign may also be seen in renal tumors (e.g. oncocytoma) - see spoke wheel vascularity - kidney.

Pathology

The vascular supply of meningiomas is often both dural and pial. Pial branches usually supply the innermost part of the tumor but arterial feeders to the pedicle at the site of dural attachment and center of the lesion typically arise from branches of the external carotid artery and in particular the middle meningeal artery.

Radiographic features

The feeder arterial branches diverge radially into the lesion; this gives the appearance of a spoke wheel on T2-weighted or post contrast images, or during angiography.

Dural masses