 Okay, let's turn our attention now to inflammatory diseases and we'll start with labyrinthitis pacificans. Labyrinthitis pacificans is the end stage of any insult to the inner ear. This commonly occurs as a result of meningitis or trauma if you allow that surgery is a form of trauma. Surgery is probably the most common reason that we encounter this, at least in North America. There's two phases of labyrinthitis pacificans. There is a fibrous phase where fibroblasts infiltrate the labyrinth and displace all of the normal fluid. And then there is a bony phase where bone infiltrates and replaces those fibroblasts and the whole thing whites out on CT. And we can distinguish all of the acute, the fibrous, and the bony phases of labyrinthitis pacificans on imaging. So here's an example of an acute phase. We see that there is intact structures here, the vestibule, the semi-circular canals, the cochlea, but they're all abnormally enhancing on this post-contrast T1. This is the acute phase, the active inflammation within the labyrinth. The next phase that we're going to look at is the fibrous phase. And you can see that although the inner ear is well seen on this T2 on this side, here all of the inner ear structures are ghostly and almost missing, right? Now we don't know whether this is the bony phase or the fibrous phase yet, because we don't know whether that's filled with bone or whether it's just filled with tissue. So we're going to look at the CT on that same patient and we can see that from a bone perspective everything still looks normal, right? This is the fibrous phase where you can't detect it yet on CT. You can only detect it on MR by displacement of that fluid. Now eventually we're going to end up in the bony phase here and you can see that the basal turn of the cochlea is being encroached on by bony structures, filling in posterior to anterior. This is early bony phase of labyrinthitis pacificans. If you allow this to go on for long enough, it looks as though the entire labyrinth is gone, just little traces and ghosts of where the labyrinth ought to be as it fills in with bone.