Dyke-Davidoff-Masson syndrome was initially described as changes in the skull seen on skull X-ray in patients with cerebral hemiatrophy, but is now applied more broadly to cross-sectional imaging also. It is characterized by:

• thickening of the skull vault (compensatory)
• enlargement of the frontal sinus (also ethmoidal and mastoid air-cells)
• elevation of the petrous ridge
• ipsilateral falcine displacement