 With that, I'm gonna check the questions and answers again. What is the cause of subdural effusion and hypotension? That's a good question. So presumably there's actually negative pressure in the subarachnoid space so that it's actually exerting sort of like a vacuum on the hacky meninges to the point where it's actually pulling basically the dura and causing the subdural effusions to occur. So that's what we believe is happening basically. And that's what we believe is causing the enhancement as well. It's causing inflammation. Do you stent vocal venous sinus stenosis in patients only have tinnitus? Ooh, that's a really good one. So I will often do their full workup. I'll do their LPC, see what their pressure is. And if their pressure is very high to the point where I'm worried about them, then I will often offer them the venous sinus pressure measurements. And I do all this away. So I'll basically do an LP. I'll tell them, hey, your pressure's 30. You're lucky that you don't have papillodema. Let's go ahead and do venous sinus pressure measurements if you're okay with it. And I'll just flip them over and do the venous access and just quickly. I use a very small micro catheter. So I don't even give them that much heparin. So it's safe to do on the same day. I give them like 1500 a heparin. And I just throw in like a five-french diagnostic catheter, like usually a baronstein or a vert or something. And then I'll throw like a Prowler select plus through. And then I'll measure the pressures all the way across. It's like 10 minutes of added time. And then in most cases, like if the pressure gradient is there, I'll just tell them it's there and then we'll have a big conversation in clinic. But I can tell you, I've never personally stented anyone who just had tinnitus. I've stented someone who had tinnitus and bad headaches, but never just tinnitus. Okay. Next question. What is the specific sign of imaging studies for NPH and not any kind of hydrocephalus? Ooh, I don't think there really is the specific sign for NPH and imaging. That colossal angle that we were talking about really just predicts atrophy versus hydro. I don't think there is an imaging specific finding. It's just a general gestalt that there is enlargement of ventricles. It's out of proportion of the degree of overall volume loss. And that colossal angle is narrow to the point where we suspect hydrocephalus. It really is a clinical diagnosis. And that's what I fall back on. Anytime someone tries to push me on NPH, that's generally what I do. So someone's asking what the stroke volume cutoff. Is there any role? Oh, sorry. This thing is, man, I'm getting a lot of questions real quick. So the cutoff that I use is 100 because we have GE machines. And then in which side are CSF venous fissures more frequently and in what level? Ooh, that's a good question. I find them to be more common, actually on the right side of the patient and more common at the thoracolumbar junction. And I think the reason that that happens is because of the pressure. Actually, yeah, I think it's just because the pressure is a little bit lower. I mean, there's less interference with the fistula forming because you're closer to the IVC, closer to the, also closer to the azagus, hemi-azagus system, et cetera. Let's see, what about A genesis of the transverse sinus? Oh, that's a good question. So A genesis of the transverse sinus, I've never seen bilateral. I've seen it unilateral in the setting of a contralateral stenosis. And in those cases, a lot of those patients doing that benefiting from a stent. But yeah, A genesis is a good thing to think about when you're talking about stenosis. So that's where the gradients come in when you're actually measuring the pressure gradients. You need to make sure it's significant. Let's see here. Regarding fallout hydrocephalus, is there any objective score that can be used? I assume they mean for NPH. No, there's not really an objective score that I've used. I'm not aware of one. That being said, somebody's saying crocrum k-rad scale. I've not used that. I just, I look at the close angle and it's, oh, Kiari 1.5, yes. How can we determine normal pressure hydrocephalus in the background of generalized atrophy? Oh, that actually gets back to the close angle. So that's a good question too. I mean, that close angle tells us basically that it's probably more likely hydro and not just generalized atrophy because the normal close angle is actually usually greater than 100. If it's less than 80, it's more likely to be NPH. But I don't use any other scoring system because I don't think anything's reliable. I just, as a gestalt, I look at it that the ventricles are bigger than I would expect for the degree of volume loss. And I just measure the close angle if it's positive. Then I just say this is suggestive to NPH in the appropriate clinical setting. And then the neurologist evaluates the patient and they say, yes, it looks like NPH. Then they send them back to me and I end up doing the LP or a three day lumbar drain trial. And if it's positive, then they go to shunt. Occasionally, like I said, I'll do a flow study and just see if it jives with my flow diversion, or sorry, my temporary flow diversion. Particularly if they're immobilized and they can't walk. Let's see, do you use CT and MR Mylo in the same setting? How much MR Max contrast can be used? Okay, so I personally never use more than 0.5 intrathecal gadolinium, I usually stick to 0.3. As far as I'm aware, there's no FDA approval for that. I normally just tell them it's off-label and actually put it in a consent that this is off-label. And that's usually what I will do. Do you use the NPH scale from Scandinavia? No, I don't use that NPH scale. Let's see, about intracranial hypertension. What do you think is the most reliable MRX? Honestly, optic disc cupping and optic nerve sheath dilation, I think is probably most reliable in intracranial hypertension. I see empty cellas all the time and it means nothing. The other thing that's pretty reliable is diffuse sinus narrowing in the appropriate clinical setting along with those findings within the optic nerve sheath. So if you have diffuse sinus narrowing, particularly along the spear sagittal sinus as it transitions into the transverse sinuses, if you have narrowing right there, a lot of those patients have NPH. Patient 50 female CSF leak, history of direct head trauma last 20 years. What suitable imaging needed? So from nose, oh, okay. So I normally do a super thin section max face to see if I can see it to hissins. And then I actually go to nuclear medicine pretty quickly. And when I do the nuclear medicine scan for those patients that I'm looking for CSF rhinorrhea, I actually raise their pressure substantially. I take them to 35 centimeters of water with Elliott B solution right before, sorry, right after I inject the nuclear medicine tracer. So for Zandia, it'll be my LP. I confirm I mentioned intrathecal with a little bit of iodinated contrast. Then I inject the radio tracer. Then I inject a lot of Elliott Bs or you can inject saline and get them up to 35, just intermittently monitoring. Also, you kind of tolerate to their, you kind of titrate to their tolerance. Some people won't get to 35. If you can get them to 30, even 25, that makes a difference. But if you leave them with a CSF hypotension or even a normal pressure, you might not elicit the leak. So I typically try to get them around 30 if I can, even for that. And then I normally have my ENTs packed the nose with Pledgeits right before and we actually count the Pledgeits. You can also do thin section T2s through the anterior skull base and try and see if you can see the CSF leak. There are some cases where you can see that his it's a little bit better on thin section, T2 cube or Fiesta imaging, compared to just a plain maxillofacial CT, but that being said, seeing the dehiscence you're relying upon, seeing a tiny, usually assigned a tiny encephalocel, basically that's what you're looking for. How to differentiate small perineural cysts from CSF leaks on planes and you can't, it's impossible. If the patient doesn't have, if the patient has a prior MRI of the brain and they do not have a positive burn scale score and they don't have symptoms of CSF leak, then it clearly is just a normal perineural cyst. But if they have signs of CSF leak on MRI and or clinical, then you just have to report that there are perineural cysts in all these locations. And in general, if you've already done that, you could ask your tech to go ahead and try and do a Fatsat T2, but that's gonna add a lot of time to your scan. The Fatsat T2 is really useful. If you go back or if you remember back earlier when I was showing a Fatsat T2 of that young lady who had the lumbar puncture, you could see stranding in the epidural space. So basically on the Fatsat T2 around a perineural cyst, you can see stranding in the epidural fat when there's a positive CSF leak. And that can help you kind of focus on one perineural cyst. I think that probably is what you're asking, basically a Fatsat T2, but on a standard scan, you can't tell if a perineural cyst is gonna be a leak or not. You need the Fatsat T2 at minimum to be able to tell if it's really suspicious. Threshold for stroke volume to be CSF low study. Again, I go back to the 100 microliters for G or 42 microliters for Siemens. But I still rely ultimately on a temporary flow diversion, meaning like a lumbar puncture or a lumbar drain. Is there any significance using needle gauge ties when doing, yes, there is significance. So when you're looking for a high flow leak, somebody asked a question about what size gauge needle to use. So if you're doing a high flow leak, you need to be able to inject the contrast really quickly if you're doing a DSM. So I use a 20 gauge needle to be able to inject it quickly. That being said, if you're doing a high flow leak in CT, presumably you got the head up for a while and you're actually injecting slowly. The sort of the distinction is that in a DSM, the patient can't be moved. So in a DSM, you already have the head down. So you have to inject quickly and wait for it to flow up. Whereas in CT, you can inject the entire volume and drop the head. You can't drop the head and do a DSM as easily. It's theoretically possible if your table moves really, really quickly for you to drop the head and quickly subtract and then before the contrast runs in. But I tend to use the smallest gauge needle I can for the low flow leaks because I don't want my puncture to obscure the leak, basically. So I try to use the smallest thing I can. The good compromise though is the GERDY set. So there's a GERDY set out there that I think it has a 20 gauge coaxial. It's about an inch and a half long and then a 22 gauge pin cam that goes through it. I've had a lot of luck with those. So for those sort of leaks where I'm not sure if it's high flow or not, if I think it may be a type two lateral leak and it may be kind of high flow, then I'll use that GERDY set. It's a good compromise. But when I think it's a low flow leak, I tend to use a 25, basically a discogram set more or less. What needle should we use for diagnostic LPs? Like I said, I tend to use that GERDY set for diagnostic LP if I'm worried about CSF leaks. If I'm not worried about CSF leaks, I'm trying to do a very quick assessment of whether or not someone has NPH. I tend to use a bigger needle because I don't want to sit there all day. So I tend to use a 20 gauge needle and I have this 33 inch one meter tubing that I hooked to the 20 gauge needle and I actually raised the head of the bed up and I actually dropped the tubing down lower. And generally I can finish a high volume LP in about 15 minutes. So our epidural CSF leak surgical emergencies like hemorrhage, they can be if they're really fast. So if an epidural leak is extremely fast to the point where the patient's comatose, it can be an emergency. I've run into those situations where I don't even have time to localize them and I take exactly what I do. Usually the epidural space is so engorged because of the leak and it's so soupy for lack of a better way of saying it. You can put almost anything into the epidural space. So I'll take a vascular forefront sheath and actually just use like a twoy needle and get my twoy needle in the epidural space. I take a really steep angle into it. And then once I get in there, I'll put like either an 035 or a nitrex wire into the epidural space and I'll put either a four French radial or just a small four French vascular sheath into the epidural space. And then I'll put like a vert, a four French vert or a four French baronstein catheter over an 035 wire. And I will run a catheter all the way up the dorsal epidural space to the cervical thoracic junction. I will patch them with 125 CCs of blood, generally injecting about two to four CCs per level titrated into the patient's ability to tolerate it. But that's how I deal with emergent leaks like where I don't really have time to localize it like the patient's comatose, I need to do something fast. So I'll put in a catheter and just inject a lot of blood. What is the anticoagulation policy for venous stent and follow-up? So I normally will give them aspirin and plavix for three months, I do check levels for those. So I checked P2Y12 level and aspirin verify now and I send out whole blood platelet aggregation for ADP and for the AA levels because they're more reliable but they're 24 hours in that lab for us. So if the P2Y12 level is less than 194 and the aspirin's less than 550 I normally feel comfortable proceeding. And then I'll wait for the final numbers but generally I like them to be below 50% when I'm putting in a venous stent on the ADP activation. And then for AA I like them to be about the same below 50%. What is flow compensated fiesta for this point? Essentially, we put on EKG leads and we're actually timing the patient's heart and we're compensating for flow based on when their heart beats because when their heart beats their brain pulsates essentially. I mean, we're actually compensating for essentially when their heart beats and when the CSF is moving. So it's almost like gating. I mean, and you can do it that way. Another way, there are a couple of other ways to do it but I'm not a physicist full disclosure. There are other ways to do flow compensated fiesta but you can gate based on the heartbeat. And then there are a couple of other ways to do it but in general, flow compensated fiesta is helpful because it removes a lot of different artifacts. Fiesta itself removes truncation and then the flow compensation removes the flow artifact so that you can see those epidural collections much more easily but you can either gate to the cardiac cycle or there's a couple other tricks. And again, I'm not a physicist. I don't know all of the tricks to that but I have a very good physicist here and they do really nice flow compensated fiesta as far as and that's how I see a lot of my CSF leaks. Okay, I think we have all of our questions and answers done. I really appreciate everyone sticking around to the very end and I hope this was helpful. I know it's a lot of information to throw at you all at once and it's as comprehensive as I can get about the specific topics that I'm talking about in this amount of time.