 This is a 52 year old man who is in a deceleration injury and I am confident that all of you are focused on the bifrontal encephalomalacia from prior trauma. Let me scroll a bit and take your time and have a look as I scroll up and down and see what catches your eye. There are multiple areas of white matter signal alteration. The patient is shunted. You can see a little bit of the shunt tube right here to your left. I have my arrow on it. And perhaps a few of you are dialed into the thickened Pia and arachnoid. Something is rotten in the state of Pia and arachnoid. And what might that be? Let me go to the midline of a T1 spin echo non-contrast image and then I have on the far right a contrast enhanced image in the coronal projection of the same patient. What are you thinking? I am thinking that this is a shunted patient and the question is how is this shunt working? And shunts, as you guys know, can stop working or they can work too well, which is the problem here. Well, ventricles aren't big here. They are small. And also look at the enhancement of the Pachy meninges. This is not leptomeningeal enhancement like you would see with the tumor or something. Pachy meningeal enhancement. So that is one finding. Ventricles are small. So my idea of something is rotten in the state of Pia and arachnoid is wrong. It is actually the dura mater, the Pachy meninges that are actual. The Pachy meninges. That is correct. If you look here on the T2, there is thin extra-axial collections. So we are kind of mounting up a couple of things. Extra-axial collections, small ventricles, shunted patient. What is the next thing we are going to be looking for? Let's look at the sagittal. You guys probably are very familiar or maybe familiar with the diagnosis of intercranial hyper tension. Remember, empty cell, optic nerve sheath dilatation. What about hypotent? That used to be called pseudo-tumor cerebri. Pseudo-tumor cerebri. So hypotension is the flip side. And this is a problem that somebody like me has helped to create because hypotension is just an atrogenic form over shunting. You did it. You are a very bad man. So look at the, this one has a very good finding which is part of the constellation but you don't see as often. So hyper tension, pseudo-tumor cerebri, empty cell. There is a big pituitary. Something is decompressed here. So this pituitary is large. So we have a constellation of findings, packing energy, small ventricles, extra-axial collections and a big pituitary. So those mount up to a lot of the potential findings of intercranial hypotension, shunted patient. So hypotension due to over shunting. Let me put it up, let me tie it up in a neat little package because what has actually happened is the surgeon created low pressure in the brain so what happens? The other structures compensatorily get bigger. So if you look at the axial, you will notice that the superior sagittal sinus and the lateral sinuses if we can get down there are a little bit prominent. They are blowing up to fill up the space. So that is one side. Now let's look at the veins. The veins down here are prominent, you can see them right there. They are blowing up to fill up the space. The pituitary gland is blowing up to fill up the space. Things are sagging down. Look at the monopontine distance. That's decreased. The optic chiasm is pressed down on the pituitary gland. You have got Pachyminigial enhancement and here again is our enlarged pituitary gland. All these findings come together in a neat little package to give you the diagnosis of not spontaneous but rather post-surgical intracranial hypotension from overshunting. Correct. Done. Thank you.