MRI
MR signal characteristics include:
T1: variable
~50% high signal 4
the rest are hypointense or isointense to adjacent brain
T1 C+ (Gd): only rarely demonstrates thin rim enhancement, but usually this represents enhancement of the adjacent and stretched septal veins 3
T2: variable
most are of low T2/T2* signal (short T2), related to thick "motor oil" consistency fluid 4,5
some have central low T2 and high peripheral T2 signal 4
some are homogeneously high signal
FLAIR: cysts which are of low signal on T2 will appear similar to attenuated CSF on FLAIR, and are thus difficult to appreciate 4