Epidermoids can be differentiated from arachnoid cyst on MRI by:
C i.e. Restricted diffusion Epidermoids can be differentiated from arachnoid cyst characteristically by hyper-intense diffusion weighted images because of restricted diffusion of epidermoid cystQ. FLAIR and proton images are less specific than DWI.
Contrast enhancement
Smooth margins
Restricted diffusion
CSF signal on FLAIR
Restricted diffusion