Figure 26.

Ethmoidal and sphenoidal menigoencephaloceles. (A) Coronal CT image reveals a bony defect in the left cribriform plate (white arrow), with a well-defined polypoid lesion protruding into the left-sided ethmoid sinus and nasal cavity. (B) Coronal T2W image reveals that the lesion correlates with herniated left frontal lobe parenchyma, CSF, and meninges through the bony defect (red arrows). (C) Axial CT image in a different patient demonstrates a bony defect in the left lateral sphenoid sinus wall (white arrow), with opacification of the left sphenoid sinus and left posterior ethmoid air cells. (D) Axial CISS image shows herniation of the anteromedial left temporal lobe, meninges, and CSF through the bony defect (red arrows).