Case 6 Answer.

Answer: cerebral edema

This was an early post-cardiac arrest patient that never came back neurologically. In hindsight there is some beam hardening artifact on the right (didn’t persist on window/leveling). Check out the vents - slitlike (in an adult). Also no grey-white differentiation at the caudates and cortical junction. The symmetry makes it touch and without window/leveling it probably was rather difficult.

Reference: http://radiopaedia.org/articles/cytotoxic-cerebral-oedema