Tuesday, September 6, 2011

Arachnoid Cyst

Axial T2
Axial Flair

Axial T1


Axial T1 post gad

DWI


Most important differential:
Epidermoid Cyst (sebaceous cyst).

Differentiating points:
1. Arachnoid cyst shows no restriction on DWI, Epidermoids highly restrict!
2. Arachnoid cysts lose signal on FLAIR (iso to CSF), while epidermoids will be hyper to CSF on FLAIR.

Nail Gun accident..

81 y o M, shot self with nailgun.



Entry wound in right temporal bone, exit in left.



What's your Dx?

CT

Post contrast CT


Axial T1

Sag T1
Axial Flair




DWI

ADC