The leveling refers to the contrast of black versus white. The IACs
were not seen well on the pictures you gave me. As the scan
is electronic, this can be adjusted using software.
The normal variant of sigmoid sinus and jugular bulb is the way that you have always been, and is not the source of your problems.
This area enhances because it is a vascular structure and the contrast is being shown on the MRI.
Hope this helps!