Thanks very much and good evening, everyone, and welcome to tonight's webinar. And tonight's webinar, I guess is a little bit different from some of the webinars that we've done where we're talking about specific subjects and hopefully sort of updating on a very specific area. This is a little bit different in terms of sort of introducing you to something that's quite new to veterinary medicine, which is interventional radiology.

Interventional radiology as a field in human medicine that's expanding quite quickly over the last couple of decades in terms of trying to do surgery and interventions as minimally invasively as possible to try and minimise morbidity and mortality to patients. And there's quite a lot of techniques that we can still from the human field to apply to our patients, and that can be quite helpful. The intervention radiology essentially means that we're using radiology to try to help further what's happening with those patients.

And essentially that's using fluoroscopy, so moving X-rays to allow us to see in real time what we're doing with the patient. And that may be placing something like a stent, so tubular metallic structure in a vessel or a lumen to keep it open. And the vast majority of procedures that we'll talk about the interventional radiology this evening will be doing that.

Or to go into a vessel so that we can, try to deliver chemotherapy to a very specific area or to embolize an artery so we can stop bleeding within the nose, for example, or, to try and, close a shunting vessel, for example, in the liver if we think about intrahepatic or systemic shunt. So, tonight, I'm not going to show you or teach you how to do any of those procedures because they're, they're quite complex. If the things that I need a lot of equipment with a fluoroscopy, for example, but really to talk through a few of the cases where we are able to, discuss where this may be, helpful for us in terms of trying to, improve our utility in those, patients and what applications we might have, in terms of trying to help improve things, for those specific cases.

Yeah. The sound. I wonder if you would mind phoning in for us to see if we can clear that up a little bit.

OK, perfect. So we're talking about, essentially stealing interventional techniques from human medicine and applying them to our veterinary patients. And there are a lot of techniques and a lot of instances where this will be quite useful.

So tonight I'm just going to talk through some of these cases and some of the times where we used some of these procedures to try and help to improve our patients. So I guess for us when we started using interventional techniques, when we started using stents, the airway has been the most common area for us to place them. So to kill stents or to kill claps is something that we use quite often, and we'll talk about those.

One of the other webinars I've done is talking about that in a lot more detail. But we've also used them in other areas that can constrict in the airway, so the nasopharynx, so at the back of the nose, both in cats and dogs, and they're quite successful, in the bronchi, so keeping those open if there's just very focal claps. And then another body.

As well. So in the oesophagus for esophageal strictures, in the colon, where there were rectal strictures, or in the urinary tract, and urinary interventions are really useful where there's obstruction, even in the ureter, when we place the urethral stent, which is a very small stent that goes between the kidney and the bladder, it can be quite tricky to place those, and I'll show you some pictures of how we do that. Or urethral stents, so we place them in the urethra, mostly in, in male dogs because of prostatic carcinomas or urothelial tumours in both dogs and bitches.

To try and help to improve urine flow, and this can be really successful to help improve the quality of life for those patients, with neoplastic disease. They don't necessarily change the progression of the tumour, but being able to urinate gives them a good quality of life for, for a good period of time. So, you know, 3 to 6 months, just with the placement of the stent, which is quite good.

And then we'll finish off talking about intravascular applications, so how we might attenuate intopatic port systemic shunts and how we might chemoembolize tumours. Just as an example of how we can use interventional radiology to try and address some of these more challenging intravascular approach. So they're slightly different techniques, but all of them, essentially rely on fluoroscopy to allow us to, see what we're doing and be able to guide the placement of a stent or to be able to see where we are in the vasculture or in the urinary tract to be able to do the procedures.

So I'm very happy to answer questions as we go along. If there are any questions later, I've I've written quite extensive notes just to give you a sort of flavour of what we're talking about and to pick up on any of the things that we don't have a chance to talk about this evening because I can't talk about everything where interventional radiology would be useful, but if there are cases or things that sort of pique your interest, then please let me know. I'm very happy to chat through them.

And there are centres in the UK, really sort of advancing interventional radioy that's the, the. The various fight international group of of people led by Chicke and Alison Brent, who really are the sort of people that have moved into vent radiology into the vein field, but ourselves it's quite referrals. Fitzpatrick's are doing a lot, and willows and and and Davis, but I think most of the big referral centres have an interest in this now.

So it is something that's becoming a lot more common across the UK. So, this isn't something I can teach you to do. This is me learning, and we very much learn as we go along with interventional radiology.

It's something that is a little bit foreign to us in terms of, of placements of, of stents and things, watching and learning and, and then doing it and then teaching is, is really helpful. But we'll place stents. So this is a metallic stent here, the image at the top of the screen in the nasopharynx in a cat because of nasopharyngeal stenosis.

This is a tracheal stent, so placement of anitinol stent, so, titanium nickel alloy to keep the trachea open that was collapsing. This is one of those urethral stents that we were talking about because of a prostatic carcinoma, keeping the prostate open. So we've got urine flow, and we can see contrast flow across those, and I'll show you how we place them.

And then this is a, a, a shunt with coils that are embolizing a shunting vessel which is stopping flow through those. We'll pick up on all of these examples as we go through this evening. So when we're thinking about stents and the placement of stents, there are essentially 3, well, 4 different types of stents that we use.

There are ones that we replace with the balloon, so these are a meshwork or a framework of stent that comes in a collapse form. And as we expand the balloon, the balloon opens and the stent opens to form the structure of the balloon. And these are really useful in areas where we want to mould the stent to that.

So the nasopharynx would be a classic example of that. But they're not very strong stents when you compress them. You can squash them quite easily.

So, in the airway or in the rectum, they, they're not gonna have a very good use and in the urinary tract, similarly, they can be squashed quite easily. So, essentially they're used in areas where there isn't movement, so within a bony cavity like the nasopharynx is the best place for them. And then we have self-expanding metallic stents, and we have traquille stents, and this is a traquil stent here, which is a woven stent, and this is really good where we have movements, so they flex and they move as the trachea move.

And then we have laser cut stents, which are ones that just open to a very set size. It's really tricky with the traquiel stents. You can see the sort of woven stent.

It comes in and it's, it's squashed when it's in the delivery sheet, but as you release it, it opens to a wider diameter, so it actually gets shorter. I'll show you pictures of how that happens, whereas the laser cuts stay at the same length and the same diameter, so they have good compression of the opening so they keep the area open once they've been deployed. So these are really useful within the urinary tract, and in the vasculature and we use them quite nicely.

And then lastly, we have dissolvable stents, so stents where we might want to place them but not leave them there for too long. So in the oesophagus, for example, we can have stents made out of material like some of the dissolving suture material that stays in place and that keeps the stent open, the oesophagus open for a period of time, so maybe 3 to 6 months, and then dissolves and then goes away and hopefully, the problem is solved as a result of that. So there's difference in flexibility between the stents, the kill stents, we want to have quite a lot of movements.

They need to be mobile. We try and minimise that movement as much as possible because it can cause irritation to the tissue, but you can imagine as the dog moves or the cat moves, it's gonna need to have some functionality, whereas with the laser cut stents, at the bottom, we've got a framework. A meshwork which is open, but it doesn't need to have the same degree of flexibility that's there.

So it doesn't matter if that degree of flexibility isn't present, but movement does tend to fatigue stents and we'll get metal metal thresh and fracture result of that. So we try to, to minimise movement wherever possible and replacing stents into our patients. So just wanted to talk through these cases, and we'll start off talking about this dog here, which is Branson, which is a, a dog that has nasal angiostenosis.

This is a little bit unlucky because well first he had anna angiostenosis, but first he was only born with one descended testicle, so he was cryptal kid and he had a, a, a liking for eating all sorts of things that he shouldn't, which is a habit of, of Labradors, and he had a, a surgery to remove a foreign body from his stomach about 5 months before we saw him. But he'd gradually recovered from that operation but developed a stor and a a nasal discharge and when we saw him we documented that he had a a nasal ngela. And this has, has caused him to have difficulty breathing through his nose, so he could only breathe through his mouth, which is causing him to have difficulty when he's holding a bowl when he was eating, his breathing would get worse when he was exercising, he was managing quite well because we would see that there was normal airflow, through his mouth as a result of that.

So we could do some investigations to, to look at this, and you could see that at the back of his nose here, the nasal nasopharynx is very constricted and there's a lot of scar tissue here. I think what happened with this dog when he had the the foreign body surgery was that he'd refluxed under anaesthesia. And this doesn't happen very often, but we've seen a few of these cases now where dogs and, and both cats have had material that have refluxed into the nasal pharynx and they've been asleep.

The erative effect of the gastric, material and, and the infection that can happen as a result of that causes scar tissue, and this causes a narrowing in the central area. And if we compare that to what we'd expect to see in a normal dog with a, a nice wide open nasopharynx with cranial openings on both sides of the nasal septum looking nice and open, you can see that this is very narrow and it's going to cause constriction to airflow. And the more constricted that is, the more resistance to airflow there is, the more rotation and inflammation is going to occur as a result of that because of that backwards and forwards movement of air across that area.

So it's important to try and dilate that and keep it open to try and help improve things. Now this is an MRI image. We probably do CT now, but we, we had MRI on site when we, we did this, and this is a sagittal image of the nose.

You can see the nasal turbinates here. This is a kindle opening here, there's a little bit of mucus here. And this is where the stricture in the stenosis is.

So the soft palate here going down towards the mouth and normal. You'd see there's a nice wide area where air can flow through the nasopharynx and into the airway, but we've got this single solitary area where there's constriction just in the front part of the nasopharynx, which is what we're seeing on endoscopy when we were looking from the back of the nose looking forward, but there's this area here that is very narrow. Well, we've got a narrowing like that.

We do like to, to sort of stretch it. We can put a balloon caster into that area, and stretch across it, which will keep it nice and open. But the more you stretch something, the more inflammation you cause, and the more fibrosis that tends to, to occur as a result of that.

So with, with nasopharyngeal stenosis, the reports of just single balloon dilations being quite effective, but often we have to dilate them on multiple occasions for that to be successful, and often actually we end up facing a stent of framework or meshwork to keep that in position to try and keep that area open. With this look, we did actually sort of do bling dilation on a number of occasions. This is a fluoroscopy image.

And when we're talking about fluoroscopy, it's the same as an X-ray image, but things are reversed. So when we're looking at bone on an X-ray, it'll be white, when we're looking at a bone on a fluoroscopy image, it will be black, so it's the other way round. So here we can see the dog has its mouth open.

This is our endoscope looking around the back of the soft palate towards the area where we're looking at the stenosis. So this is the view of the endoscope that would have given us the view of the stenosis, which is just here. And then we've passed the wire and a balloon catheter through the ventral meatus of the nose into the nasal pharynx, and you can see the The balloon here, which has got contrast in it, so it's a little bit dark, but it's narrow in the centre.

So you can see that the balloon has a waist here, so it's constricted in the centre because of the stenosis that has formed across the centre of the balloon. So we have a stenosis here that we're dilating with the balloon cater, and hopefully we can keep that open as a result. We did this several times with this dog, but it, it was very effective for about a week each time we did that, but then those signs would come back.

So ultimately, we placed a stent across that area and you can see the stent in the centre of the nasopharynx here, which is causing the area to be open. You can see the stent quite nicely in position, which is allowing The stenosis to be kept nice and open. So this is the central part of the stenosis, and you can see that the stent is, nicely positioned across the osmosis.

It's kind of got that dumbbell shape where it's nice and open on either side, but there's still a little bit of narrowing in the centre, but you can see that there's a nice sort of opening across the laser ynx, and it looks very nice. This is sort of what we started with, with a very small area in there. So pharynx is a very constricted area is airflow is gonna be quite limited through that central area with the balloon dilation to try and help improve airflow through that area, and you can see that it's improved a little bit.

And then we've placed the stent into that area and we've really sort of forcibly opened that area. You can see that it's gonna get much better airflow as a result of that. And this stents designed to stay in place.

It's an ismal stent, so it's a very inert and metallic structure based on, titanium and nickel they use in human vascular procedures, and the vascular stents stay in place for the rest of your life. So they're not thought to be things that are going to cause a problem. And we've moulded this to the internal diameter and dimensions of the nasopharynx.

So this so forward, it's, it's probably not gonna cause too much of a problem, but the caudal edge potentially could have movement as the soft palate. It's a little bit up and down, and that potentially could then sort of constrict and cause issues. But this dog did really nicely and very well.

And we did see him back a few months after the initial placement of the stent because the caudal edge of the stent had slightly narrowed. You can see that the stent rather than being that sort of dumbbell she has sort of become a bit flattened, and it's flattened at this back edge here because the soft palate is moving up and down a little bit. So we can just place a balloon into that just to sort of keep it open.

And squash it and keep it into position in the mesopharynx, and that stent then will become embedded into the wall and we'll see me cos growing over the top of that, and we should be able to keep that stent in position, so the scent pair back in position in the way we would want and this dog did really nicely. He was a really active Labrador and went on. To manage to do everything we would expect him to do, to breathe normally through his nose, and this is about 6 or 7 years after the procedure now, so he's doing really well with that imposition.

So from being able to stretch something repeatedly, placing the stent allowed that to be kept open, and really improve the sort of functionality of his nasal sign. So that's neoangeal stenosis. I'm gonna now talk about tecure claps for a little bit, and I think tecu claps will be something that's quite familiar to everyone, especially with the really hot summer that we're having.

Where the Taki is collapsing and making it difficult for air to move backwards and forwards, we have these dogs come in with really sort of pressure risk because costs that is quite irritated in terms of the amount of noise that they're making, as the Shakira is collapsing as they're moving backwards and forwards, that's causing a problem as, as things are, moving and there's airflow moving backwards and forwards. So still claps is, is, you know, graded from 1 to 4 from quite mild when we have about a quarter of the tier, collapse. So up here, stage, grade 1, which is the first picture, grade 2, grade 3, and grade 4, and grade 4 is where we have almost all of the ki claps as a result of the cartilages losing their structure, and the IFO is gonna be really poor through that.

With most animals with steel plants, we try to medically manage them, and there are lots of things that we can use for medical management weight loss and anti-inflammatories, and antiulsives, and we use a lot of dioxylates in the form of flamay or umloloil which can be very helpful in terms of managing airway inflammation and coughing associated with it. But if you've got grade 4 tracheal collapse like this where you've got a, a trachea that essentially if you're looking at an endoscopically looks a bit more like an oesophagus than it does, trachea, you're gonna really struggle to manage that medically, you really max out all the things we'd expect to do, but every time the dog breaths in, it's just gonna suck both sides of the trachea together and you're not gonna be able to keep it open. There are various ways that we can try to keep the tequila, and one of the sort of classic ways of doing that is to use extra tequi prostheses, and these are a little bit, rough and ready.

These are syringe barrels, rings that are cut around to provide some external curation and support for the ski. You can now buy custom-made ones if you know what the diameter of the ski is. There are companies that will be able to supply these for you, but, they work really nicely in the extra thoracic part of the ska.

So in the neck. If you're trying to get into the thorax and and doing that within the within the thoracic cavity, it's really tricky to be able to do that. And once they worked really well, there are a number of comorbidities that can go with this surgery because we've got the recurrent illness that are quite close by.

There are some quite big blood vessels that are quite close by and you've obviously got to put these wings all the way around the kia. So it can be quite difficult to be able to do that. So angio paralysis and, and problems with bleeding, are the most sort of common side effects.

So if we can identify focal plats in the extrathoracic part of the trachea in a young animal, then this sort of extra thoracic prostheses to keep the tea open would be really successful in enabling us to do that. But if we have the whole of the tea that is collapsing, and an older animal where this is really quite an invasive procedure for us to do, then potentially placing a stent within the trachea like this is a much better way of trying to approach it. This is a procedure that we can do within the lumen of the trachea, and it takes you maybe 5 to 10.

It's to be able to place it a lot longer to work out what the correct sizing is and to get things right in terms of the procedure, but it enables us to be able to place a stent in position that allows airflow without the dynamics of breathing, causing the ki to be collapsing and making it difficult for air to move back and forward. So these are these woven lyinal stents that we were talking about. These are made by Infinity Medical.

There are a variety of different stents that are available, but these have the nice form of being woven, so they've not got the sharp edges that we see with some of the original stents, which were billary stents that we used. And have quite a lot of granulation tissue associated with them when they were put into the trachea. Essentially we're using things that are available in human medicine for our specific indications, and these have been purpose designed, to be able to be used in our patients and have a lot more flexibility, than those initial stents.

So those nice woven edges just mean that we don't have the sharp parts that are present when we're putting them into the animal, and they tend to be associated with a lot less granulation tissue as a result of that. The tricky part with traquiel stenting is getting the sizing right, and this is the traquille stent in its open form at the top of the screen. You can see that it's nice and it's round and it's the sort of shape that we want it to be.

But if you squash it and if you put it into its delivery sheet as it is on the bottom, it's a lot longer than you'd expect it to be. So it becomes longer as you squash it. This means that we need to know what the diameter of the trachea is and understand how long the length of the gear that we want to stent will be.

Usually we stem from about 1 centimetre from the larynx to about 1 centimetre in front of the cline of the bifurcation essentially. So we sent the whole length of wherever that is possible. But as we're delivering the tent, as we're releasing it from its delivery sheet, we can see that it's gonna get wider, essentially this sort of foreshortening effect.

So we have charts to know that this stent, this is a 12 millimetre in diameter stent by 77 millimetres long. We have charts that know that if we put this stent into a 10 millimetre tube, how much longer it's going to be, because it's going to be longer than the 77 millimetres in. That 1010 millimetre tube.

We put it into an 8 millimetre tube, how long it is. And unfortunately, dogs kias aren't nice and even. They're not the same diameter all the way along, so they can be, they can get divergent, so they can be, sort of wider at one end than they are at the other, and these sort of diverging stents, we can sometimes have them custom made so that they're sort of conical or tubular and those do tend to work quite nicely.

So we tend to try and work out the length of the sk we need to stand, and we also work out the diameter all the way along. And we tend to oversize by about 10 to 20%, so there is a little bit of compression of the wall, not too much and not too much the scent is squashed a lot because if it's squashed a lot, it'll want to get back to that normal size, and that can cause a problem as well. So the size I think can be quite tricky when we're trying to do that.

So in the thing, we use a marker caster like this. So this is fluoroscopy looking at the trachea. We've got the markercaster in the oesophagus.

These marks are 1 centimetre apart. They're from the frontage of one to the touch of the next. It's a centimetre, and we've got the tube right back up into the larynx.

So it's right to the larynx up here, and this is the cricoid cartilage here. You probably can't see it very well, but there's a faint black stripe here, and this is the, the maximal edge of the traila that we'd want to stent. And then we can go all the way down to kia to the bike.

Which is his crier. So you measure along that length all the way along, extending about the centimetre from the crioid to a centimetre in front of the crier. We can stand further back and further forward if we want to, but we risk caging off some of the bronchi if we come too far back.

So we don't really want to cage across the, right cranial bronchus which comes off a little bit before the bifurcation or to send into the larynx. People have done it and it doesn't cause too much irritation as long as you can get to the vocal folds, but we try not to stand past the cricoid cartilage. So we can work out the length and the diameter and you can already see that this dorsal border isn't straight, so this is a slightly wonkishka.

So it's always done under positive pressure, so 10 centimetres water to really maximally inflate the as much as is possible. This is the other view that we often do, just really to try and work out what's the length of the extensiveness of the care. This is negative pressure.

This is really coming from when we used to just send vocally the area that was collapsing, but I think the more dogs we've looked at, the more we've realised that it's the whole length of the care that is collapsing. So here we've essentially apply negative pressure, so if you get 10 centimetres of water, looks pretty horrific because you can't see the dog's oesophagus, but this. Has really severe qui collapse.

So this is sort of the normal pressures that would be present through breathing. So this is sort of equivalent to it, the pressure we generate trying to breathe in, and you can see that there's really just like a straw type length of its airway here, quick it is up here again, and then the bifurcation down here. So this really shows that we need to spend a whole length of this dog's, trachea to make sure that we can help improve his breathing.

So let me choose our stent we've got the right size and we've got the right diameter. We do want to stent from about 1 centimetre in front of the bifurcation and start delivering the stent. These stents are reconstrainable.

So if we've not delivered it in the right place, once you've released about half of the stent, you can reconstrain it. So you can put it back into the sheet, you can move it, and you can start to reconstrain. It redeliver it again, which is really nice with the trachea.

The other senses we'll talk about the vascular ones and the one in the urethra, where you start to deploy them, you can't put them back into the sheet. So you have one go at it. You give them that these cost about 1000 to 1500 pounds each, and it's one of those things where you have to just take a very deep breath and hope you're in the right place.

Most of the time we will be, but it's not unheard of. It it's slightly wrong or just need to place a second cent because the delivery hasn't been ideal, but that's one of the things that you learn about quite quickly with interventional radiology, in terms of making sure you're in the right place. There's a really steep learning curve in terms of doing this and, and getting the delivery right, which is why I guess we've learned most of our experience with skills sense, and then we've kind of gone to other areas as as we've gone on with time.

Once we get past the halfway point, we'll just keep slowly sliding back the delivery sheet, and that allows the stent to, to come off, and it will pop off the delivery sheet and the stent will be left in the right position. And you can see here we've stented from just behind the crier just here all the way to, to just find the quick here. So this stent position looks really nice.

Got nice wall acquisition on both sides, so there's no obvious. Of any guttering, so really pleased that things look quite good with this dog, so we'd be fairly happy with that, and is gonna keep running, so we then want to take an X-ray just to make sure everything's OK, and we can see that the, stent looks really nice. It's in a nice position, looks really good in terms of our position against the wall, and we would monitor these very carefully to make sure that there aren't problems.

Few issues that we can see with stents and they really come from inflammation of the edges. This is the older style stent that we're talking about, the biliary wall stents. So the, the sort of biowy stents that are used to keep the bile ducts open.

They have these sort of frayed open edges, which don't cause. Much problem in your system because there isn't too much movement, but in adults, to care because there's a lot of coughing and a lot of moving back and forwards, they can cause sort of irritation and inflammatory tissue, generally tends to respond quite well to steroids and colchicine, but now we have the nicer woven-ended stents, they tend to be less of a problem. And the outcomes are, are quite good.

If you compare them to the outcomes from the surgeries, the outcomes of the stent placement is much better. The idea with placing a stent really is to help improve bleeding, so to make these animals go from being very dystonic to not dysic. Had to try and reduce the amount of movement there is in the secure wall.

So we're not going to stop coughing associated with the stent placement, and it's really important that we still go on to use medical management to try to make sure that we can control that coughing, because the more coughing there is, the worse the outcome is going to be. So we've got some really good improvements where these dogs go on to be, you know, very asymptomatic, have really good quality of life. A lot of them are improved and some of them can still be quite symptomatic.

And that's probably because Shaquille lats isn't usually the only problem that's present in those dogs, so they can have airway issues that cause bronchial plats or clots of the lower airway. And just hoping the Shaquia will help to improve things, but it may not sort out. Problem completely.

So, people have found that stent placements have worked really nicely and people have have been very happy with the outcome and improvement as a result of that. But it's really important that we know, that the stent placement isn't the only thing that we need to do to try and control things. All the medical management that we have in place so for medical management, your clients needs to be present so so harness walks, trying to make sure weight is maintained.

All of those sorts of things, and we generally have them on a low anti-inflammatory dose of steroid in the longer term and use anittussis to make sure that these dogs aren't coughing and monit them really closely, so we tend to take full up radiographs every 3 to 6 months to make sure that there aren't problems. If there are issues with stem fractures or complications as the agulation tissue, the sooner we can try and address them, the better the outcome is gonna be as a result of. So those are the airway indications that we have.

We'll move on a little bit to talk about the urinary tract before we finish off talking about the vascular approaches. And these are where we would want to help to allow the passage of urine more freely. So we start off talking about urethral obstruction, and then we'll talk about urethral obstruction.

So we're starting off talking about the urethra and problems and difficulties in passing urine, from the, bladder and, and avoiding it out of the body. And this is Barney, he's another unlucky chap. He's got a prosthetic carcinoma, he's very well in himself, but he just is, is really stray.

He's really finding it very difficult for him to pass urine. He's just. And straining all of the time, and that's really affecting his quality of life.

He has a tumour that is present within the prostate. It's about 3, 3.5 centimetres in diameter.

It's not the largest of tumours that's present, and there is a little bit of spread to the supple lymph nodes and the draining lymph nodes, but it's not affecting any of his other organs in his body. We know that prostatic carcinomas are a relatively slowly growing tumours, but they cause effects locally that can really have problems on quality of life. They're quite difficult to treat with chemotherapy and we have had some success treating them with intraarterial chemo chemotherapy and other sort of metronomic type protocols to try and slow their progression.

But essentially, if you've got to the point where it's causing a constriction and a difficulty in the passage of urine, placing something like a stent to allow the prostatic urethra to be open to allow urine to be passed through that can really help to improve. Of life, and then the disease will just progress. We'll see the prostate gets bigger, it will spread to some of the lymph nodes and ultimately will go to the liver and the chest and cause problems with quality of life as a result of that.

But in that sort of 3 to 6 month period, maybe longer depending on what the tumour is, he can urinate freely and have a good quality of life as a result of that. So basically a resource sense in that sort of instance can have a really good outcome. And we've seen quite a lot of these dogs where actually that's been a really useful thing for us to do.

As you can see, if you look at the prostate here, and this is a, an endoscopic urethroscopy image that we're up, looking at the prostate, round beyond the the arch looking towards the bladder, that straight part of the urethra that goes towards the bladder, really inflamed looking wall of the urethra, as the tumour is sort of going through, and then as we come through, we're just sort of getting towards the bladder there, you can see off into the distant flats, that's the bladder itself here that we're getting to a really marked and inflamed urethra. So urethral stents are really useful where there's strange area. So prostatic carcinomas for transitional cell carcinomas, which are now more correctly called urothelial cell carcinomas, Rests, so problems we've seen after injury or catheterization type effects, extremal compression.

So if we have problems with some lymph node enlargement, classically. With anal site carcinomas, and that can cause restriction of the urethra and cause a problem and sensing those has been helpful. And some people have experimented with it with reflex this sign energy where you have spasm this urethra.

Normally we would medically manage those, but if we can identify a very focal portion of the urethra, which is sad we can potentially send across that area and that also has helped, to improve quality of life in those locations as well. So the aim is to take a dog like this that can't pass urine, and here we're doing a retrograde study. So this again is a fluoroscopy image.

We've got a catheer. You've probably got the vascular access sheath that is in the prefuse here in the penile urethra, and we're injecting contrast, which is the, the black yinated liquid up here, into the prosthetic urethra, and you can see it abruptly stops as we come to the proststatic urethra. No contrast comes through a very wispy stream of contrast that comes through until we get to the bladder.

So this is another dog with a prosthetic carcinoma that is, is here. We can see that's causing, some difficulty in passage of the catheter within the rectum of the mark. I idea of size so we can measure what sort of size stent we would need in terms of length and diameter.

But our, our passage of the contrast is affected as a result of that. So what we're aiming to do is to place a stent across that area so that we've got an open lumen to the urethra. So when again we pass contrast into that and we slit that contrast forward, we can see that the obstruction that was present, is no longer in place and we can see that we've alleviated that by the presence of the stent, and that's a, a nice way of being able to improve quality of life as a result of.

So how do we do this and how do we sort of measure for that? Well, we do need to have some catheters, and we need to have access into the bladder to be able to see where those parts are. So here we have a bones by caster which is in the bladder.

So normally we use a vascularar access sheath in the, in the penis, usually go up with a wire. So it's a, a hydrophilic wire, which just gives us the ability to drive and, and to move. It's got a twisted end.

You can turn it and and and move it through the the urinary tract and more importantly when you go through the vascu so that happens. And then once we're in the bladder here, we need to be able to identify with the bladder neck it so we put a little bit of contrast into the bladder so we can highlight where that would be in exactly the same way as we would do with the retrograde study if we were looking in a dog or a bit to try and evaluate the lower urinary tract. So once we've got contrast in the bladder, we can then do the retrograde part of the study.

So we've moved the Bernsteincastheer back to the, to the pelvic arch here. So we know that the constriction is through the the prostate here, which is just in front of the pelvis. We've got a marker catheter in the rectum.

So this is a marker catheter centimetre marks again, it's got a wire inside it to give it some gy and it's inside a red rubber catheter, so it's not gonna cause any damage to the the colon when it's in. And then what we do is to inject the contrast. We just inject the contrast quite forcibly so that we can inject it into the bladder.

And you can see that as the contrast runs through the bladder, it's narrowed, and there's this kind of apple coring type effect. You can see that the nice wide pelvic urethra becomes quite constricted as it runs through the prostate. So there's constriction here as the dog tries to urinate, it's not gonna be able to avoid the urine effectively because of this constriction here.

So this is the area that we want to stent to try and alleviate some of the obstruction that's present. So we'd sent from just about the bladder neck here, all the way back to where we're getting normal urethra. We normally spent about 1 centimetre past where we would be, so we were sent somewhere to the edge of the the pelvis here.

We use the marker catheter for landmarks and often we'll use a measure underneath the table so we can see where those landmarks are once the contrast has gone away. So hopefully we can then measure the type of stent that we need and we would measure the diameter. I think this is a 10 millimetre wide stent by about 80 millimetres in length.

And these are laser cut stents, so these are stents are gonna open to exactly that diameter unless there's constriction. So we know it's never going to be any wider than than 10 millimetres, and if it's narrower than that, it's gonna try and press against the wall, so it's not going to become dislodged or stuck as a result of that. So here we're sliding the stent up over the wire, so we're getting it up towards the bladder.

That is always the case, our weasel wire is moving back in the opposite direction, which shouldn't really happen. So we're getting the stent into the right position. So when we're wanting to get the stent in position, we get the neck of the stent into the bladder so that when we start releasing it, we can get it into the, the right position.

So this is the stent moving up and going across the prostate, and then we'll remove the wire. So we want the wire to be getting stuck between the stents and the, the urethral wall. And this is the, the sort of position that we want the stent to be in the first part of the stent to be in the bladder and then stenting back to about the pelvic brim, which is where we wanted it to be.

And then as we release the stent, we just kind of open it and we sort of just get the first part of the stent to open. We put it back into the neck of the bladder and then release it across the prostate. So we just open the first part, pull it back so we engage it, maintain a little bit of pressure across it and release it across the prosthetic urethra.

So it goes into position quite nicely, and we could be quite happy with the placement of this stent. So the next step would be for us to then repeat the retrograde study where we're just gonna inject the contrast. So we've got our burns like catheter back in position just for the pelvic brim, and we're gonna pass contrast through.

And you can see really nicely that contrast moves into the bladder really well, and this dog did really nicely. There was a good improvement in the dog's quality of life. It's able to urinate effectively.

I think actually it's about a year later that he was put to as a result of progression of this disease, so he did really well as a result of this, just really from alleviation signs because of the stent placement within the prosthetic urethra rather than any modulation of his disease process. So there are various studies of this, and, and there aren't huge numbers of cases that have been reported, but the sort of best case series is still about 10 years old. It's just 42 cases that were submitted for abstract in 2010.

From, Alison, chicks group in the states, so, AMC, New York, American Medical centre, did, did very nicely with a lot of their dogs, but they did see a degree of incontinence in those, patients, so 1 in 4 developed incontinence. Most of those dogs improved over time, so we generally tend to see about 10% being inconstant now, and. Then a lot of those dogs do improve over time.

So it doesn't seem to be the length of the urethra that's stented that seems to be a problem. So you kind of imagine if you were stenting a length in a, in a dog, it might be less likely to be incompetent if you were stenting a bitch where the length of the urethra is much shorter. It doesn't seem to be associated with the length of the urethra.

It's more about the urethral dynamics, the stenting floss of the bladder neck, and that probably is more of a risk. If you're having incontinence, and if you're having the issue arch in a, in a male dog not being affected, so there is some closure at the end of that, then again, the, the urethra is, is generally fairly good. So it's taking one problem, I guess, of not being able to pass urine and perhaps in a small portion of dogs replacing it with, with too much likelihood of them passing urine, but these dogs have a better quality of life as a result.

So it tends to be improved as a result. So those are urethral stents. I think a little bit about urethral stents, and we're not gonna talk too much about the technical challenges of placing these because these do tend to be more of a sort of surgical realm than the medical realm.

But this is where we have a, a urethral obstruction. So an obstruction in the small tubu coming from the renal pelvis down to the bladder, and that is usually with a stone, although we can see stenosis or surg. Interventions where they've been ligated at ovarian hysterectomy very, very occasionally.

And generally, this is a medical emergency because we're going to start to see signs of acute renal failure, hydronephrosis, this is this. We've got a very, very dilated renal pelvis that's gonna cause back pressure, that's gonna cause problems with the kidney, and very quickly we're gonna see long term damage to the kidney as a result of that. So you can try to medically manage ureteral obstruction.

Using thral relaxants and and using analgesia and fluids and then try to move things along, but it can be really difficult to do that, and it generally takes quite a long time for that to happen. So placing a stent within the ureter, so from the renal pelvis down to the bladder, allows a conduit for urine to move through, but it also allows the ureter to laze around it, and that can be really helpful in terms of allowing the passage of urine. This is the sort of situation where that would be quite helpful.

This is a a a a polycystogram. So we've got a catheter here into the renal pelvis of the left kidney. We're just going to inject some contrast into that kidney so that we can follow it.

One of the things that's happened here is that we've got digital subtraction, so you can see all the anatomy to start off with, and then everything went white, and went blank and Now you're just seeing us inject the contrast. So this is one of the nice tricks that fluoroscopy can do using interventional radiology to make it clearer, see what's happening. So here you can't see the background very nicely, but you can just see the contrast within the renal pelvis of the kidney, and then the ureter, which looks quite dilated, and it's coming down towards the bladder and then as you get to this area here, there's a stone which is Present, which is causing some obstruction.

We're quite forcibly injecting the contrast, so a small amount of contrast is getting into the bladder. So you've got this blush here as a result of that, but there's obstruction here as a result of the stone that's present. So this is probably going to be quite tricky to move through medically.

It's going to be hard to get it to move down to the bladder, and placing a stent to allow that to move through can be really helpful. We just watched the video again. You can see that there is obstruction as a result of that.

This may be one where we might manage with this, but, but placing a stent to overcome that obstruction would potentially be an option in terms of management for this sort of patient. So what do we mean by a stent? Well, what we mean is a, a nice sort of pigtail catheter which is lodged up in the renal pelvis that moves through the ureter, comes into the blood.

The pig tail which is in the bladder itself, this cannular this cat is a little bit too long, probably should be a bit shorter, and this is a cat that has bilateral ureteral stents, in most of in your pelvis. So these pigtails are in your pelvises. These stents are lying through the ureters down into the bladder, and you can see there's quite a loss of stent here that is present within the bladder.

So you tend to cause too much of a problem. Some cats will have some cystitis-like signs as a result of that, but we have a very crass kind of measurement we have, we have 69, and 12 centimetre long stents, so it's a little bit difficult to judge in some animals exactly how much material that would be left in the renal pelvis and in the bladder, but, most cats that quite nicely. There are two ways essentially of, of placing these.

The first, which we tend to use in cats, is where they're placed anterior rate. So you use the needle that you do your polocentesis or polycystogram with to gain access into the renal pelvis, pass to wire down through the ureter, hopefully bypass the obstruction and go down to the bladder, so you've got a coil of wire that is present in the bladder, and then you can slide your stent over the top of that wire so that the pigtail ends up in the bladder itself, and the pigtail ends up in the renal pelvis. There are various ways of doing that.

The other option is to do it, which is called retrograde, which is either to make an incision into the bladder or cysotomy or to do it endoscopically, which is better in dogs because you can visualise the ureteric openings, feed your wire up into the ureter so you get your wire coiled up in the renal pelvis, and then you can push your stent retrograde up into the renal pelvis so your pigtail curls up in the renal pelvis, and then the stent is nicely positioned as a result of that. Sounds easy. It's actually technically very difficult to do that, and many an hour in an operating theatre trying to get into the position, but there has been a very steep learning curve with these, and the first sort of 10 that you do are horrendously horrible, and then after that they do, they do get easier, but you need to have that degree of experience in terms of placing them, to be able to get them into position.

But once you do, you should have a stent which is called up in the renal pelvis, and the stent that goes down into the ureter, which then comes into the bladder and lies against the bladder wall, and most animals will tolerate these quite nicely. The tricky part is getting them into position. And that's the difficulty here.

We've got the, the wire coming down into the renal pelvis, going down the ureter, into the bladder itself. We just sliding the catheter across it here is the pigtail here, which is ending up in the renal pelvis. So we've got the pigtail nicely in position with the renal pelvis here.

And then the next video is just removing the wire. So we're just gonna take the wire out, so we're gonna Withdraw the wire back down towards the bladder, and you can see as we do that, it's just wiggling around a little bit here, but as the wire comes back, we're just left with the, nice, curls of the pigtail catheter at the top here and then the cannula is in position down in the bladder at the bottom, but they're they're challenging things to place, but if we've got your teric obstruction, then they're a good way of trying to overcome that. Because they're technically challenging, the surgeons have come up with other ways of trying to manage this.

So this is, what's often the surgeon, for a user, bypass device, that enables you to, essentially get you from the renal pelvis to the bladder, but without having to place one of those tubular structures within. Ureter. So you're leaving the ureter in place, not trying to address the obstruction, but essentially you're placing two different parts of the cannula from here, the renal pelvis to this subcutaneous device, which allows you then to have another cannula that goes to the bladder.

So material and urine can run from the renal pelvis within the kidney down the tubua that you've inserted to the bypass device and then from there to the bladder. So essentially you're making an artificial ureter, that is going to the bladder. You can do that on one side or here as we have done with, with two sides, and this is a, a, a bilateral, so diversion device which is work unless it's for bilateral ureteric obstruction.

You can see that there's some mineralized facing up here within the renal, the some of the space which. Probably material of oxyate crystals within the ureter and there's some quite big nephroliths as well which are probably contributing to the obstruction. So in these animals are subcutaneous, ureteric diversion devices is a good way of trying to alleviate the obstruction that's present.

We would always try to place stents if possible, but if the obstruction is too difficult, then we can place these. The benefit of a stent is that you can always take it out, and if the phone is passed and it's not needed, then it's a good way of removing it. With a sub it's always going to be present and because it's a foreign system and the urine is probably a little bit more fatty than it would be within a normal system, they are prone to developing infections, so we're super, super careful to make sure we're very clean with how we handle these, and we flush them on a regular basis.

Firstly, to make sure that there isn't any evidence of infection, but also that they don't become encrusted because these animals are usually being scented or having these devices placed because of, of obsolete crystal urea and stone obstruction. We don't want that to occur within the sub-device itself and cause problems as a result of that. So we're usually flushed every 2 to 3 months, and we tend to use strictly GTA to enable us to, dissolve in material that my presence, but also to avoid any bio film that might form on the inside of the sub, part, that could sort of make it more likely these animals develop, quite nasty, multi resistant infection.

Because they're my pockets on the place. So these work quite nicely again, the little button that you've got here enables you to do that, sort of exchange and injections. So you just sit under the skin within the muscles of the abdominal wall.

You can just use a Hoover needle which is, sort of sharp at the end like a, normal hypodermic needle. It's, it's got a slightly bent end, so you're putting a, a, a rounded end of the needle through the, seal so that the rubber seal isn't damaged, and then you can take samples of culture and you can do slashes. And there are various protocols that are written up for doing these where you can look at the renal pelvis, and the bladder when you're doing the fluxes to check the pain of the club, and that just helps to make sure that there's no problems with any obstruction or any infection that might be present.

But this is another route, for potentially overcoming the teric obstruction, and generally it tends to be done when the stem placement isn't appropriate, so either it's gonna be too challenging, it's too difficult, the anaesthesia will be too lengthy to try and do it or it's failed, as in it's not possible to pass. Then pass the obstructions causing a problem and then placing a sub is a good way of trying to overcome that. And generally we try to place stents so you just have a bit of a rule that if it takes more than about half an hour or so, then we'll just move on to placing a sub straight away afterwards, and these work quite well.

They've got these pigtail catheters that have these cuffs around them which, are just then, sutures and glued to the, the pelvis, the kidney, tend to work nicely and the same with the bladder, and they tend to be very inert and then very well tolerated so they're they're nice things to be able to. So those were the urinary tract interventions that we talked through. We talked about the respiratory tract ones, they're gonna sort of finish off talking about intravascular applications.

So we're gonna talk about intraopathic systemic shunts for a minute, and then talk about intraarterial chemoembolization. And I guess in human intervention radiology has really come from the stent placements that we see in cardiac disease, with, vascular disease causing heart attacks and thrombosis and, and problems with vascular supply as a result of that. So catalys and human hospitals are really quite busy with these patients, and we've borrowed a lot of this knowledge of this in vascular work to be able to sort of fix some of the problems that we have.

And I guess one of the sort of first indications and where it became most useful was working in the in the venous system, and it's much easier working in the venous system than it is in the arterial system, as you may imagine the pressure is gonna be a little bit higher, so it's more challenging. So intraopathic water systemic shunts would be one of the sort of major implications or indications for using intravascular, techniques to try to attenuate flow through shunting vessels. So when we have portal systemic shunts, we have an abnormality in the blood supply to the liver.

And excuse my very poor cartoon-like diagram here, but in the normal animal, all the blood that comes from the intestine, will run through the portal vein. It will go to the liver, it will be filtered. All the good things that the liver does will take place, and then, blood doesn't have all the toxins and metabolic things that are, are present, from bacterial digestion in the gut that are filled out from the liver ends up in the circulation, have effectively clean blood going off to the heart around the rest of the body.

And the portal systemic shunt essentially is a, a vessel that allows a bypass of the liver. So blood coming from the portal vein ends up in, in general circulation. No, it essentially means that lots of things that shouldn't be in the general speculation end up being there.

So all the toxins and bacterial fermentation, so things like ammonia, but also branching fatty acids, endoscs, all sorts of things that can act as false neurotransmitters, end up going around the body and affecting the brain and causing the signs that we will recognise as hepatic encephalopathy. So if the shunts like this and it's outside the liver, then our surgeons can go and look for it and attenuate it, and we can tie it off completely if it's quite a small shunting fraction, or we can use something like an amyroid luda or a cellophane band around it to constrict it more slowly over time if it's kind of new vessel. So it gradually gets slower, less flow through it, and the liver can adapt to an increase in blood supply as a result of that.

But if these vessels are within the liver itself, so rather than having an extrahepathic course to some extent, if they're intrahepatic, so if they're within the hepatic parenchyma, then it can be really difficult for us to find them surgically. We need to dissect through a lot of very vascular, spongy structure of the liver to be able to find where these vessels are, and it can be very difficult to ligate them safely because it's difficult to identify first where the shunting vessel is, but also to be able to get them without causing a lot of bleeding from the other vessels that are present. So an interventional approach is something that we've sort of undertaken to be able to do that.

And what we're doing with our interventional approach is trying to coil off the portal shunting vessel as it enters the general circulation. So what we're doing intra intravascular is to identify this junction here between the general circulation and where our shunt is coming in. And this is what this sort of schematic diagram on the right is, it's enabling us to place a stent within the cordal vena cava across where that shunting vessel enters the general circulation and then for us to place coils within that vessel that attenuate it flow.

So we reduce the amount of flow that comes through the shunting vessel into the general circulation. If we stop this flow, it means that the portal pressure increases and the amount of blood that goes to deliver increases, so we've diverted the flow as a result of that. And we can place coils gradually in this so that we don't sort of place too many, a bit like what we do with the extraopathic ones where we cause a problem by attenuating the shunt too quickly and causing signs of portal hypertension, the liver not being able to cope with that.

So we can measure the pressure in this vessel and we can place the right number of shunt, coils to be able to do that. We obviously do this in theatre and we do this through a jugular approach. So here in the theatre we've got the fluoroscopy over the over the dog, which is lying on its back, and we've got a vascularis sheath up here at the top so we can remove these pictures.

So a vascular axis sheath up here at the top in the jugular running down so that we can pass wires through the thorax into the cordal vena cava here. So if we look at that into the fluoroscopy image, which is what we're looking at on the monitor, we're able to see that we've passed a wire down the cordal vena cava, which is where the striping mark catheter is here. And then we've also been able to catheterize off the shunting vessel as well.

So this here is a cannula which is coming into the shunt here, and going off around to the side. So this is the vena cava here and this is the shunting vessel that's coming to the side and we've injected contrast from two cats and the contrast is running back towards the heart so we can see the vascular anatomy quite nicely. Once we've identified where the shunting vessel is, we can place a stent across the area.

So this is the stent here across where the shunting vessel is coming in, it's coming in about here on the, the previous image, this branch to this vessel here as it comes towards the cranial vena cava, and we've placed a stent across that area so we can place coils in the shunting vessel which will attenuate the flow through it as they come back to the towards the heart. Then we can go back through our jugular access sheet with our catheter. We can pass our catheter through the heart base to the corvina cava and go through the stent so that we've got our cast on the other side of the stenting meshwork, and then we can place these little coils and you just go through the cannula, and then when we release them they form this little meshwork, these little rings of of TFE which form a clot, a thrombus that will stop blood flow from being able to move through it.

And once we've delivered enough of those. We can see that we've got this nice bulk of coils that are present. And when we inject contrast into the shunting vessel here, we can see that that contrast accumulates and doesn't move back through into the, the corvica in the amount that it was previously.

So the contrast is accumulating here because the calls a stopping flow. We need to measure the pressure here quite carefully because if we put too many calls in too quickly, that will cause bottle hypertension and cause a problem. So it's not uncommon with these quite wide shunting vessels as is present here.

This is, this is quite a big shunt to go back and place more coals on a second occasion so that we sort of reduce the amount of shunting, blood flow on the first occasion, allow the liver to adapt to having more blood flow and. Back and put a lot more calls in the second time so we completely close off the shunting vessel, and then hopefully have improvement as a result of that. So this technique works very well.

And there are lots of studies that show that the outcomes of introopathic courses shunt are better with attenuation in this way, compared with medical management, which is the difficulty in terms of placing a large number of calls as a result of that. So this is a nice way of being able to do that and we can get some quite cool radiographs as a result, this is the this centre across where the shunting vessel enters and here we place about 20 or so coils across there. So it's a lot of coils that are placed in position.

This is what I mean about how to get these in the right place. You don't want to put these vascular stents in the normal position. These are measured off of CT, so we know we've got them in the right place.

These are about 1000 pounds just for the metal work, so they're quite expensive pieces of kit, and the cores we're looking at about. Sort of 30 to 40 pounds per coil. So, it's usually sort of looking at sort of 40 to 5000, if not more for the actual procedure for, for, for doing inopathic shunt surgery, but it's a very nice way of being able to address the problem because we've just got jugular access, the jugular access sheet, so our only incision is into the jugular so we access with the sheet to put wires down into the vessels to be able to identify where these structures are rather than having it to dissect through all the hepaticcula to be able to find where those areas are.

So that's port a systemic shunts and then the, the last thing I just wanted to talk about in terms of another vascular application before we, before we finish this evening is, is intraarterial chemo embolization and, and, and trying to attenuate blood flow to different areas. And we often use embolization for difficult problems with, with bleeding, in human medicine, for example, if you had intractable nose bleeds, they would try and, attenuate the blood flow to those areas. Veterin medicine, if we have a nose bleeds that won't stop, very rarely we sometimes ligateed arteries to try and stop that from happening, and that, that will be tolerated quite well.

But with interventional radiography, we can find the artery that is, bleeding, this is where contrast is leaking. And we can attenuate that with little be particles which cause clots in those vessels. But we can also identify tumours and the blood supply to those tumours, and we know that the blood supply to tumours allow them to grow quite rapidly, and that means that we can reduce some of the blood flow by embolization, so using little beads that block the arteries that supply those areas, but also deliver chemotherapy specifically to that tumour, and this works really well in areas like the.

Or the prostate, where historically we haven't done very well with systemic chemotherapy doses to those organs very well, but we know if we deliver a full systemic dose of chemotherapy specifically to that organ, it has a very good chance of having a much better effect. And with, with liver tumours and with prosthetic tumours, this is a, a good way of treating them from the human side that we've borrowed, and again, seems to have a good outcome in veterinary medicine. So lastly, this is a a dog called Kenny who's a 11 year old staff bull terrier.

And in absence of abdominal pain and had to find some quite nasty looking hepatic masses, which he'd gone to surgery for, and unfortunately weren't able to be removed, so he had a very large left sided hepatic mass which, was, was, causing a problem and a right medial lobe, mass which was also not particularly resectable as well. So he had very large tumours which were associated with the liver, which turned out to be quite aggressive cellar carcinoma. But these are putting quite a lot of pressure on abnormal organs.

It's putting pressure on the stomach, causing him not to be able to, to eat. And we went to surgery to try to see if we could resect these hepatic masses, and that wasn't possible at surgery. So, our board of surgeons were, were not very keen to be able to remove these because they were associated with a lot of, of material and, and vessels, and it was very tricky to be able to do that.

And you can kind of understand the, the reason why when you look at the ultrasound, the whole of the screen here is just filled with heterogeneous tumour. This, this is normal looking liver and then it's very abnormal. And then when we've done the CT scan, you can see that there is this very large mass which is present on the right side here, and this is a tumour that's causing a problem.

It's causing a sort of squishing effect. All of these other organs are over here, so stomach is here, the normal part of the liver is here. So, the normal abdominal organs are quite squashed as a result of that.

And we can look at the blood vessels that supply this tumour, and you can see that the tumour here marked by these little, little arrows that are present, this kind of spaghetti network of vessels which is present. And we know that the anatomy of these vessels from dissection and anatomy text, we can go, go down these vessels to be able to drive into this vessel to the tumour to be able to get the right lateropathic artery to be able to give potentially intraarterial chemo. Chemotherapy, but also potentially to embolizeze these vessels as well.

The the liver is is nice because it has a dual dual blood supply. It has an arterial circulation, but it also has the portal circulation as well. And normal liver takes most of its nutritional oxygenation from the portal circulation, so about 80% of normal liver metabolites and oxygen come from the portal vein and about 20% from the arterial circulation.

We know that the tumours that develop in the liver is the other way around, so tumours tend to take about 80% of the nutritional oxygenation from the hepatic arteries and about 20% from the portal circulation. So we can attenuate the hepatic tumours arterial supply quite nicely, and we specifically solve the tumour of oxygen and nutritional supplementation, compared with the normal liver have such established portal supply. So if this mass isn't resectable, which we know she's been to surgery and that isn't possible, the next step would be to potentially consider trying to see whether we could attenuate blood flow to this tumour by attenuating it with an embollic agent.

And while we're doing that, potentially deliver some intraarterial chemotherapy, something like doxorubicin or carboplatin to the tumour and then embolizing it to recreate an anaerobic environment with a high dose of chemotherapy to see whether we can get the tumour to shrink. Now that's easier said than done, I guess, because what we need to do is to drive through the vasculature to get to where that tumour is. So we need arterial access to be able to do that.

So these areas were very, very motivated, and I guess that's one of the things we need for some of these procedures, but this is a CT scan of the mass, so it's the other way around now. This is the mass over here, this is the network of vessels. This is the aorta.

So we're gonna gain access through a femoral catheter, so a femoral cut down, place an access sheath so we can drive up with our wire, and then a cannula come up through the, artery that supplies the area, the apatic artery, and then drive to the, artery that's. Applies just that lateral lobe of the liver so that we can get to the area. So we know that the vascature here is is quite complicated.

This is the celiac artery that is coming off going towards the liver. We've got the splenic artery that goes off to the left, the left gastric artery, and it's the common hepatic artery that we want to get to, and we want to get to that right lateral hepatic vein, which is the one that's supplying our tumour over here, but the left hepatic and the right hepatic tend to split fairly keenly off the common hepatic artery. And then we have the gastroduorenal artery, which is one that we don't want to mess with too much because it goes to the stomach, but also to the pancreas and the DDA, the gastroduveal artery is something where we don't really want our chemotherapy or embolic agents to end up because embolizing or delivering high dose of chemotherapy directly to the pancreas, is not a very sensible thing to do.

So we want to specifically just get that artery that's causing the problem. So we can drive our catheter through the aorta down towards the area where we know those vessels are, and then we can inject contrast to enable us to see the anatomy in that location. In that location, we can see that we have a, a very nice picture.

I just see it a little bit so we can see it a bit more clearly. We've got a catheter in the common hepatic artery. This is the right lateral hepatic artery which is going to the tumour, which is where all this spaghetti network is, which is the artery that we want to get into.

We want to go into this sort of hooked little vessel here, and then we can identify the latopathic in the, the gastrogenal artery and leave those well alone because that's not the area we want to get to. So we usually use quite a large cannula to get down to that area and then use a very small micro catheter, sort of a very selective catheter to drive into that lateral branch of the hepatic artery. And then once we're into that area, we're using selective angiography again to be able to, to minimise the background, just inject the contrast into that area.

And you can see that we've got a really nice kind of tumour blush. We've got into that lateral artery and we've got around that sort of corner that goes towards the tumour and then there's this kind of Spaghetti like very unorganised pattern of blood vessels here. It doesn't look like a sort of branching tree that we would expect to see within normal liver as we're in the tumour itself.

So once we get to this point and we're in that vessel sort of supplying the tumour, we can give firstly our chemotherapy. So we give a systemic dose of chemotherapy directly to the tumour and then use small PVAB, so these are about 200, 200 microns in diameter or something like that. They go a little bit in size to block all the arteries.

So we give the systemic dose of chemotherapy, and then reduce the arterial supply to the. To enable us to essentially make it a hypoxic environment. And hopefully that helps to, to reduce the ability of the tumour to grow, to, to shrink it in size and enable the chemotherapy to be effective as a result of that.

And in human medicine, this is a very successful way of treating inoperable hepatic tumours. It's associated with what CC causes post-symbolic fever, and usually you become yorexic for a few days. Generally, there isn't a process or problems as a result of that, but, generally it's, it's not a very nice feeling for a few days, but generally the tumour shrinks roughly about at half its volume over the following 2 or 3 weeks.

And that's exactly what we saw with this dog when we've been able to embolize the human from a situation where it had a very nice arterial supply like this on the left to one where when we're injecting contrast, most of the contrast is moving off to the. To the left of the screen and very little is going to the tumour itself. So we're both able to selectively embolize that area, reduce the blood flow to that tumour.

So you can see here this is the blood supply, the tumour around that kind of hook, and there's lots of vessels that have come off it. Here after the embolization, you can see the hook, but then it stops and all the spaghetti vessels are, are missing. So we've done a very nice job in terms of embolizing that.

And we saw that the tumour did reduce by over half its its its size, . A little bit of time for that to happen, about a week to 10 days, reduced, from about 170 mLs in diameter to about 80 mils in diameter post embolization. So a very nice way of being able to reduce its size.

Fortunately it gradually grew again over the next couple of months and we re-embolized it and it reduced in size, but then we grew again and and caused problems automate sleep as a result of that, but. They still did very well as a result of being able to we've done a few of these now but have, have worked quite nicely. Generally they have a couple of days of not feeling too good in the hospital, but generally with analgesia and anticyorexics, they, they do quite nicely come home maybe 2 or 3 days afterwards and have a reasonable period where the tumour reduces in size, and quality of life, improves as a result of that.

It's obviously technically quite challenging to do, but it's. Nice way of being able to reduce the size of liver tumours. We've also been able to adapt that technique to be able to give chemotherapy to things like prosthetic tumours where giving out a whole dose of chemotherapy directly to the prostate.

They tend to embolizeze the prostate because it only has a single art supply has related to to reduction in size of the prostate, and that also helps if replacing stents to delay the progression of the disease, and that can be really quite useful as well. So hopefully that's a a bit of a snapshot of some of the procedures that we can do in interventional radiology. I know I procedures that probably aren't appropriate or practical for you doing a general practise service so at the beginning this is information you're gonna be taking home this evening, and, applying to clinical practise tomorrow, but just wanted to.

Give you a flavour of some of the things that we're exploring with interventional procedures, some things that are possible with all the techniques and all of the equipment and, devices and gadgets that we have in referral practise. So thanks very much for listening. I hope you found that interesting.

I'm very happy to answer any questions anyone might have. Simon, that was absolutely fascinating. And I can tell you that I'm not alone in being incredibly jealous of all the toys that you get to play with.

Yes, we're very lucky. Folks, we have run over a little bit. I know it was worth it.

I have hung and, been intent on every word that Simon has said, and, I'm sure for a lot of us, we, we really are besides being jealous of the toys, we are very impressed with the work of, Simon and the other specialists are doing. And hopefully will give us a little bit more scope with patience and those collapsing trachea dogs that the owners just can't cope with anymore. We now know that there is another alternative.

So that's fantastic. Simon, I can't thank you enough for your time tonight, and your knowledge that you have shared with us. Thank you.

You're very welcome. Thanks for listening. Folks, that's it from my side to Holly, my controller in the background.

Thanks for all the help for getting this going tonight and we'll see you on the next webinar then. Good night, folks.