The Role of Ultrasound Fusion Imaging in Intervention - HD

Introduction

Hello, my name is Dr. Ham Chie. I am the director of ultrasound at Wake Forest University Department of Radiology.

I'm gonna be talking and discussing with you today the role of fusion ultrasound imaging and its role in interventions.

Before we start our talk, I would like to emphasize one fact. And if you look at these slides, you can see that over the years the number of CT scans and radiation exposure to the population has dramatically increased.

Now if you look at the bottom slide, you would notice that in a developed country like the UK the number is significantly less than what we have in the United States.

So this urges to try to implement new technologies to try to minimize the number of these CT scans and try to implement ultrasound and use it to our advantage in situation. We could not perform ultrasound procedure without CT scan, for example.

So the topic today is gonna be outlined in the following. I'm gonna talk about the technology and how it works and then I'm gonna emphasize the importance of this technology in clinical practice, including the role in diagnostic imaging and in intervention.

Now I have to admit to the fact that this technology really applies mainly in the second component of the discussion, which is interventional. And we're gonna see a few examples in different parts of the body.

What is Fusion Imaging

Now let's move on to what is fusion imaging. Fusion imaging combines volumetric anatomic data from CT scan or MRI with real time multiplanar imaging capability of ultrasound.

Basically what you're trying to do is you're trying to see the ultrasound and the MR or CT image in the same plane at the same time on the screen of the ultrasound system.

Now the fused dataset can be used precisely and integrate specific anatomic structures and abnormalities that you're looking for on the CT or MRI to guide you for your specific biopsies and interventions.

Fusion imaging is particularly helpful for identifying targets that might be otherwise difficult to locate by ultrasound by itself and sometimes even on non-contrast enhanced CT scan, which is usually the case.

How the System Works

So now let's look at this slide and look at the video imaging here and we're gonna discuss how the system works. Basically this is the system here and you have sensors surrounding the transducer and you have a magnetic field over there where give you information in spatial time over the patient.

And this is a representation of me personally holding the probe over the patient and moving it in different planes as you can see here.

Now what are the basic concepts, even though we call this navigation, but it really differs from what you actually have in your car GPS system.

So multiple GPS satellites, the way we know it, circled the earth emitting radio frequency signals. Now the GPS receivers locate at least four of these satellite signals to determine how far away each satellite is and uses this information to calculate its own position in time.

So the satellites positions are always known due to their predictable orbits.

Now we look at the components of the system in details. This is what I showed you earlier and you can see here the VN components, which is the magnetic field EM emitter.

And these are the sensors. So V nav system or fusion imaging uses a fixed transmitter that we call the V nav for volume navigation that emits a set of magnetic field patterns.

Now instead of GPS unit, fusion imaging uses a pair of electromagnetic sensors that are attached to the ultrasound transducer and that can detect the emitted magnetic field.

Now both the transmitter and receivers are connected to the ultrasound machine, which monitors the position and orientation of the transducer.

So in conclusion, GPS uses multiple transmitters and one receiver fusion imaging uses one transmitter and multiple receivers and hence the difference between the two concepts.

Data Import and Preparation

Now let's move on further to explain further how we use this in practice. So any imaging dataset, CT or MRI and currently CT PET images are imported into the ultrasound machine prior to fusion.

Now this system works with almost every PACS system available on the market today. So you can pull the information from the PACS to the machine beforehand and you can use it to fuse your ultrasound with the CT or MR for a planned procedure or biopsy.

The other thing, if your patients come from out of town or they are referred to you from another hospital, they bring their imaging with them on a CD DVD or even a USB stick. You can do the same by plugging it into the machine right away and make that data available to you.

So after we pull the images of the patient, the system allows you to specifically pick specific data set. For example, you can get a early enhanced version of the contrast CT study, arterial phase portal venous phase, equilibrium phase.

The same thing applies to MRI. You can get the contrast sequences, you can get the T two T one, whatever you like, where you see the lesions based on these images to fuse them with the planned ultrasound procedure.

Now the built-in software in the system allows for manual input of common points of planes and then builds transformation matrix based on this information.

So this what we call transformation matrix is then used to display the MR image from the 3D dataset that corresponds to the current live ultrasound image.

Basically this is what we see. What we see is you pick a fixed anatomic landmark on the CT or the MR, the portal vein, the aorta, the subcutaneous fat just under both rectus abdominal muscles.

And you pick your points on this to match the points on these and then the system will start moving the CT MR image with the same point and the same speed as you are moving your ultrasound probe on the patient.

Look how nice the detailed anatomy of the pancreas on the ultrasound image corresponding to that scene on the CT scan.

Advanced Features

Additionally, the system allows you to apply color doppler to the ultrasound, which is really a nice thing to can identify the vascular anatomy if you're looking for, to avoid the vascular structure during your procedure so you know exactly where you're gonna plan the path for your biopsy.

And in this instance look how nice you can see the renal vein crossing all the way front of the aorta going into the IVC.

In addition, the system allows you to use what we call target points where you can identify the lesion and pinpoint a specific spot or point on the lesion. Like in this instance there's a tiny stone in this kidney on the right side on the CT scan and the targets and the system will tell you that if you are exactly at the same spot, it's gonna be very clearly green there, you start to get out of the plane.

What happens is the box gets larger changes color telling you you should not attempt this biopsy on this. You're perfectly aligned with the green dot on both images.

So we started to implement this system in our facility in late 2008 and when we first started we only had the option to work with CT MR. We only had the option to work with everything that can be put from the PACS.

We don't have identifiers at the time to pick selected series or cases and as I mentioned earlier, you can do this now today you can select specific series of any study you have, but things got better and better and now we can even fuse a PET CT scan image as you can see here with ultrasound.

Now this is a new software upgrade and you can see the menu here in the lower right corner, which is, you can see here a magnifying view of it that can allow you to pick the CT scan by itself with the PET CT scan fused to it or you can subtract the CT or the PET from the imaging depending on what you're looking for.

Also you have the tendency to play with the scale to increase the tendency of the PET CT scan that is on top of the CT scan and you can minimize the gray scale on the CT scan.

You can pick up different colors to your liking and too many things that you can do with the system that allow you to see things better.

So if you look at this example is just this is to demonstrate to you the role of PET CT scan. Look at the magnitude of changes in this liver. There are multiple metastasis in this liver and multiple lesions and look the corresponding non-contrast CT scan and this patient barely showing anything but the patient has a PET CT scan that also part of this CT scan.

And here you go. If I click to superimpose the PET CT scan on the CT scan, basically I'm fusing the CT and the PET together on the right hand side of the screen to correspond to these lesions that you see on the ultrasound image.

Again, as I said, you have the option of picking up the color you like, this is the exact color map that you can see that comes with the PET CT scan. If you're familiar with that we would like to keep that, that's fine.

You can identify these hypermetabolic lesions there nicely corresponding to those seen on the ultrasound image.

So you also can go ahead and subtract the CT scan and look at just the PET CT scan if you want. Look at the specific lesion and see how much the activity there, whether it's look nuts, there's a large size of this but the activity is not as much as this tiny till guy in this region here next door.

So this can allow you for a more precise targeted lesion of interest to yield the best results of your biopsy.

Again, if you like a different you of color, you can change that your liking in this instance it's green over here and we now move to talk about the clinical applications and how we use this in our practice.

Clinical Applications

Hard to See Lesions

So when I talk about this I would like to divide the topic into hard to see lesions, hard to get to lesions and hard to characterize lesions by sonography.

So we all get frustrated when we get a patient to come to the ultrasound suite for a liver lesion biopsy or any other biopsy. And then we see it so well on the CT MR but no way on ultrasound we can identify it.

It becomes frustrating issue created the problems for us for the staff. We need to take the patient now to CT scan. The CT scan is busy. We need to find a spot for them to do it.

So it brings frustration to the patient. Frustration to us to avoid all this fusion imaging can help you solve this problem. And based on precise anatomic pinpoints that you pick earlier in the process, you can really go blindly and do these biopsies with a good rate of success.

So let's give an example of this look on the left hand side. This patient had a history of esophageal cancer and this is a PET CT scan follow up and shows this hyper metabolic activity behind the thyroid gland in the posterior neck.

Now the ultrasound on the other hand identify this nodule here just addition to the carotid artery. The patient has other nodules in the thyroid. The thyroid is heterogeneous, but this nodule was initially thought of as the exact thing that we see on the PET CT scan.

But if you look carefully there, this is actually the lesion is there in the back here and not this guy. So you have to go and try to target that.

This is the color doppler of the same thing. We trying to see if we pick up any vascularity here in this guy but we didn't. And then based on the information we gathered and you can see that our interest is not in this guy, our interest in the guy in the back here and this came back positive for recurrent esophageal cancer.

So now this is a quiz for you. This gentleman had a history of colon cancer, multiple chemotherapeutic courses for treatment of the disease. And you can see that this liver area here looks heterogeneous.

Does anybody see any lesion here? It's really hard to identify anything on this liver. So we decided because we know the patient had a lesion on the MR, we went, we did color doppler, we couldn't identify anything suspicious there.

So we used our fusion technology and we identify this tiny little lesion that was picked up on MRI but this at what point was larger than this about two and a half centimeters but with treatment it shrank in size but you still see residual tumor sitting there.

And we used our fusion technology with this and we managed to identify approximately that spot based on specific anatomic landmark.

So for this purposes you can see my needle now under guidance going in that area there I placed a vascular coil in this area for purposes of identification and marking of this lesion for purposes of surgical resection.

And you can see the twinkle color comet artifact there from the coil after placement. So the patient received another course of chemotherapy and six weeks later we go to the operating room with the surgeons, we identify the coils with ultrasound and the surgeon just carve a big piece in that area around the liver and the path came back still positive for metastatic cancer and with clear resection margins.

Another example of hard to see lesion is this unfortunate case of a young lady with history of epithelioid hemangioendothelioma. She already had her right hepatic lobe resected and now this is her follow-up MRI few years down and you can see that there is a low intensity lesion in the left lobe, which you barely can identify on the ultrasound.

But we managed to identify the vascular anatomy nearby in the region. And the beauty of this is you can use color doppler and the color doppler, as you can see here, identifies this vascular structure that really corresponds to this vascular structure that is in the path of this mass lesion.

So based on that information we went ahead and we performed our biopsy. So, and we did multiple biopsy in this area to cover the whole lesion as we suspected based on this anatomy and we were lucky to identify evidence of recurring disease in this patient.

Another example of situations where patients, they have the clinical manifestations of something bad happening, like in this instance, Lin carcinoma was highly suspected in this patient and you can see the imaging is really highly suggestive that but unfortunately multiple ERCPs were performed and they couldn't yield any abnormal malignant cells on the brushings.

So we were asked to try to biopsy this area of the thickened duct. The thing is, whenever you have a stent in the common duct or the hepatic duct, it's really hard to explain whether it's related to the tumor or it's reaction or it's reactive to the presence of the stent itself.

And the only way to do that is to put a biopsy and see what you may get. So we managed to identify the exact thickened area there and based on that you can see I use my target points there you can see the little T here, the little T there.

And I managed to sample that thickened wall of the common hepatic duct and we identified malignancy in this case consistent with cholangiocarcinoma.

Note the echoes coming nearby here from the lens so that you need to be careful about this and this is the beauty about real time ultrasound. You can see stuff coming in your way and you don't wanna be, you wanna make sure you avoid these things in the path of the needle to avoid complications, major complications.

Now this is another example where you can even put the patient prone try to help solve problems. This elderly lady unfortunately got a hip replacement few weeks earlier, the prosthesis got infected so they went in, they removed the prosthesis.

Few weeks later she came with fever, abdominal pain, back pain. And as you can see on the CAT scan on the right hand side there is this small fluid collection in the psoas muscle with enhancements.

So the diagnosis, this is an abscess sitting there, but now the thing is we need to sample this to identify the responsible bugs for this abscess to have a better selection of antibiotics.

So this patient initially went for a CT guided procedure. The patient had difficulty lying prone or on her side for purposes of that she had history of COPD.

So a colleague of mine asked me if I can help with fusion to identify that. Now you, I agree with you, it's not that pretty over here but if you can do the matching, you don't have to have the exact matching but you can see that there is the psoas muscle here and there are some hypoechoic areas that's corresponding to this abscess on the right hand side that you can see on the CT scan.

And based on that information we put small needle there and you can see the tip of the needle is within that fluid collection there. And we managed to aspirate pus from that and sent to the lab for bacteriology.

Now another example where you do not have to do a procedure or do a biopsy because you have the CT scan, you have the ultrasound and when things get better it's really hard to identify.

This patient had some neck pain and for a reason she got a CAT scan of the neck. And during that process there was a lymph node that was commented on the CT report and then the clinicians asked for a biopsy of that lymph node.

Now the patient did not have any history of high risk for malignancy or anything like that but the patient came for the procedure and this is an instance where I can use some anatomic areas in the patient to match the two imaging planes to find something like a lymph node in the neck.

Now the reason why I did that is because before the procedure sonographer went in to look at the neck that she said she couldn't identify any abnormal lymph nodes. But we have documentation of that lymph node on the CT scan.

So the best thing is we decide to do fusion to make sure we're not missing the lymph node for one reason or another. So I picked that colloid cyst and the thyroid, I match it with the low density lesion on the CT scan as a reference point.

And from there I went to find this enlarged lymph node. So based on the anatomy and the vascular markings surrounding this lymph node, as you can see on the ultrasound here in real time this lymph node is really here.

So that's why it was hard for the sonographer to pick up this lymph node. This lymph node is now is very small, very small, very tiny compared to what it was on the CAT scan and we thought it was reactive and there was no need to perform this biopsy.

Hard to Get to Lesions

Now we get into the other category which is hard to get to lesions. Now CT there's no, now it is an excellent for identifying an abdominal mass. It cannot always offer a clear and safe path to the lesion.

You can get bowel in the way, enteric vessels in the way or in the path of the lesion. So fusion imaging can really solve this problem.

This is an example of hard to get to lesion. This patient as you can see has a mass here in the right side of the pelvis close to the common iliac artery there and you can see you have bowel in front of it.

There's another loop of bowel in front of it over here. But we really know from our practice that bowel can change from time to time.

So we, the patient came to the CT scan and because of these limitations they couldn't do the procedure. So we said we can have, we can try under ultrasound guidance and you can see how nice here I managed to match the anatomy.

The same thing I match it. As I earlier said, I found the left portal vein on the CT scan. I found the left portal vein on ultrasound and I just bring my probe all the way down to the area of interest and there you go.

You can identify the area. So to improve my accuracy of identifying the lesion, I use color doppler of the common arteries to identify both common iliac arteries over there.

And you can see the very tiny little vascular anatomy here, which most likely is an artery going at a vein next to this mass.

So this is the mass, this is a loop of bowel and now we need to find a way to get to this mass for biopsy.

Also the system give you the advantage to overlay your ultrasound on top of the CT or MR and to get a accurate matching of the price, look how nice the color doppler is on top of these common iliac arteries.

And the color doppler is really, really corresponding well within the lumen show. I had a very good accuracy here so I feel confident now to go and perform this procedure.

So what I did because of, I dunno what gonna be in the path of my needle, I just pushed hard on the abdomen and I used hydro dissection. I injected about 70 cc to a hundred cc of sterile water there to displace the loops of bowel in the right way.

And I used a 25 gauge needle to sample this mass lesion. And you can see the biopsy came back indicative of recurrent lymphoma in this patient who had a history of lymphoma a few years earlier.

This is another example where patient's presentation comes like that. This elderly gentleman came to the ED with weight loss and of course CAT scan identify this massive matted lymph adenopathy and you can see the corresponding lymph adenopathy here at the same level.

Look at the celiac artery, celiac artery branching to the to the splenic artery. The splenic artery is splayed anteriorly by this conglomerate of lymph nodes.

But you can see the beauty of ultrasound identifying them individually as masses with some fatty plains still identified between these lymph nodes as opposed to the CT scan.

So of course the next day they asked us to do a biopsy, the patient had the same issues problems COPD cannot lie flat on his back, cannot lie on his side.

So there was no way to be able to do the biopsy under CT scan. Then I was asked to do the biopsy under ultrasound.

So while I'm reviewing the CT scan and the biopsy, I know that there is some infiltration here in the omental area in artery. So we decided to look at it with still review.

Look, this is the same plan, the still review showing you the matted lymph node here on the CT scan and look on the ultrasound you can see nicely that there is something here hypoechoic corresponding to this infiltrative process here under the diaphragm between the diaphragm and the spleen.

So I decided to go and put a needle into that and this came back as non-Hodgkin lymphoma.

Now sometimes things get more complicated like in our next example here, another hard to get to lesion. Patient has a mass anterior to the third portion of the duodenum.

You can see the aorta here you can see the IVC the spine and you can see the mass here. Within the mass you can see some vascular anatomy which is clearly defined on the color doppler.

So we were requested to do a biopsy because endoscopic ultrasound, they said it's too dangerous to do that and CT scan they said there's no safe window to get that. So we need the diagnosis.

So we cannot deny the patient the opportunity to know what's going on. So we decide to attempt to do that despite the fact that you can see the mesenteric vessels are running through this mass.

Now the good thing about this is always look at what you're trying to do in two planes. So we look at the second plane, which is the tel plane and you can see how this mass is encasing the mesenteric vessels over there and our only chance is try to get some sampling from that away from these arteries.

And that's the beauty of real time ultrasound with color doppler supplemented by fusion really improves your confidence and you can attempt to do this without this it's really hard to decide what you're doing and I feel like this thing really, really helps to increase my level of confidence to be able to go and get a biopsy from these hard to get to lesions.

So there is the mass again and you can see here in the green this is my ultrasound window where I'm scanning and I kept those vessels out of the way and again this came back positive for malignancy.

Another hard to get to lesion here is when things you can start to go all the way up to the dome of the liver close to the heart. As you can see in this instance you have the colon here, colon there, you're in the same plane.

You can see how nice I use my target points to pinpoint me to a specific area which is really picked nicely on the MR but on the ultrasound, the whole architecture of the sub liver looks so distorted so you don't know what you want to pinpoint.

This patient had a history of cancer and multiple treatments chemotherapy. So, and there's still active disease there.

So the clinicians really wanted to restage the disease and the only way is to try to get a biopsy from that low intensity focus on the MR and we managed to identify that spot.

And then on the ultrasound guidance based on that we made multiple passes that encompassing this area here and we made sure we stay away from the pericardium here.

It's very close area but we were successful to get positive results for the clinicians in this specific case as well.

Now another hard to get to lesion is we start to go to after stuff that in the past we used to say we cannot do it. Look, this lesion is so high up in the dome of the liver and it's really hard to see this gentleman had a history of pancreatic cancer and now there's a new liver lesion in the dome of the liver.

For restaging purposes of the disease process, we were requested to do a biopsy. Now under CT scan you can see all that colon, there's lung you could, could, could have done going through here but there's a diaphragm here.

Nobody wants it to attempt this. It is risky business. But again, ultrasound has the advantage that you can do and identify lesions in really different planes, not sagittal, not axial, anything in between can help you identify the lesion.

But all problems you can see here, you have to keep an eye on this guy. There is the colon sitting in on top of this liver.

So you need to move this bowel your way and the best thing to do that is use high frequency probe to identify what are you gonna be doing.

So this is the loop of bowel sitting in front of that liver which is in the way of the path of the determined needle to go to that lesion.

So what I did is again, hydro dissection about a hundred cc of saline or still water and you can see the loop of bowel start to push away from the planned trajectory.

And then using e track system that we're gonna talk about later in the process. I put a trocar here, I use a trocar system 'cause I don't want to keep going back and forth here 'cause I want one way in.

So I don't wanna lose my fluid here. The bowel is gonna migrate back in front of the needle. I don't wanna repeat the process.

So I put the trocar here and through that trocar I did multiple samples and I got results.

As I said earlier, you are not only confined to the abdomen, to the liver, to the pelvis, you can do this anywhere in the chest, abdomen, pelvis. Actually if you see the lesion with ultrasound, there's a corresponding imaging to that.

You can also do it. Let's look at this example of very magnified view of the chest. You can see the sternum here, the sternum, you an ultrasound, there's a lymph node which is abnormal intrathoracic lymph node.

But also you can see an enhancing vascular structure over there posteriorly. This is the lymph node on ultrasound and you can see the beauty of ultrasound where you can see the pleura lung interface here.

And this is the guy you need to stay away from. You don't want to hit this during your biopsy and you don't wanna push your needle so far in to sample this lymph node so that you won't cause a pneumothorax.

I use color doppler here in this instance, identify the lymph node, identify the exact lymph node, the artery sitting behind.

So now I put my plan for the biopsy, I keep the artery away from me, I put my needle and I'm so gentle with my fine needle aspiration biopsy start not to push too hard, stay away from this, from the lung and the pleura.

And this patient, although had a history of lung and laryngeal cancer, this biopsy helped restaging the disease and came back as lung metastasis.

Now things get more complicated now, but the thing is stuff that we never used to even attempt to do on the ultrasound, like in this instance very close to the vascular anatomy CT scan would be a better choice to go.

But again, patient with severe COPD and the mass in the anterior chest is really hard to keep on the CT stable still. So we decided to go ahead and attempt this under ultrasound guidance.

Yes it is not the best ultrasound image on the right hand side, but we picked the anatomic landmarks and we were confident that we are in the right spot.

So we kept the color doppler on, we kept this part of the vascular anatomy away from the trajectory of the needle over there. And here you go. Now confidently we identify the mass now and this is, we did a core biopsy of this and this came back as a primary lung carcinoma.

Another interesting example of hard to get to lesions, you can I see that this patient presented on outside facility with bilateral hydronephrosis. So at the facility they were successful only to put a double J stent on the left side as you can see on the CAT scan over here.

But you see this lump of soft tissue here. But you can tell that there is an aorta and ultrasound, there's an IVC over there, but here everything is blending altogether.

You don't know where the aorta, you don't know it's the IVC and of course there was a request for a biopsy and you can tell that we are limited for a window to that biopsy.

The pelvic bones, the spine is here so the only way is to come from the front. Now how are you gonna attempt that?

On the front on the CT scan you have all these loops of bowel in front of this soft tissue mass and there is a need to get answers for what's going on in this patient.

So again, we attempted this under fusion ultrasound and you can see the mass over there, you can see the aorta, you can see everything.

And then we did multiple fine needle aspiration passes. We tried to avoid to do a core biopsy in the setting of all this complicated anatomy.

But again, before I started, as you can see here, we did hydro dissection technique. We put some sterile water here to get rid of the loops of bowel in the way based on the CT scan.

And then as you can see I did multiple, they were negative for malignancy. And now to diagnose an entity like retroperitoneal fibrosis, the answer is to get a core biopsy.

And you can see my core biopsy needle. I placed it in a very safe place between the aorta and the IVC and I did two passes and they were conclusive for retroperitoneal fibrosis.

Now over the time that we are experimenting with this system, we start to become part of our normal schedule to take it to the operating room with the surgeons to identify tiny little lesions for purposes of which resection or ablation.

And you can look at this example here. There is this low intensity lesion in the dome of the liver, other low intensity lesions. But we wanted to localize this for purposes of which resection and we did that, we did the which we localized this for the surgeons for which resection and we after the resect we look at the same area again to make sure they took the right thing out.

Same patient has multiple lesions, history of colon cancer, young patient in late thirties. So you try your best to try to find these lesions and treat them and get them to get the benefit to the patient and improve survival.

So even though look at this, even though we are sitting on top of the liver inside the or your ultrasound probe is on top of the liver, you barely see these posterior right lobe lesions even though they are showing them so well, but they are so tiny.

But based on that information we decided to identify them and ablate them.

Another example is we go to the OR all the time to look localize pancreatic tumors and masses. This is a magnified image of a mass neuroendocrine tumor sitting in the pancreas enhancing over here.

You can see it with ultrasound fusion. The surgeon struggled at this point here on his own to find this mass.

So we came into the operating room to help him identify it. We found it and unfortunately we managed to identify that this is a very close mass to the common bile duct.

So the only way out for this is to have a distal pancreatectomy. But the good thing is you can see the ducts so nice here. The distance is not long enough.

Again, use color doppler to identify the vessels and this is also what we do. We grab a needle and we put it for the surgeon so they can cut down on it to find this specific lesion or mass in the liver, in the pancreas in this instance.

Hard to Characterize Lesions

[Note: The transcript mentions dividing into hard to characterize lesions by sonography, but specific examples under this subcategory are integrated into the broader clinical applications discussion above. No distinct subsection examples are separated in the original text beyond the mentioned categories.]

Needle Tracker Device

So I will conclude my talk by talking about another technology that you can combine with your V nav system, which is a needle tracker device. This is actually the e tracker device and this device helps you to target lesions that are off the plane of your ultrasound probe.

As you can see, this is a phantom is showing you that I'm coming from the side of this presumably liver. Let's assume it's a liver. And there is the ultrasound probe and you can identify that needle based on information provided in the screen that will guide you and tell you that you're going in the right direction.

So it's an excellent technology, it's an excellent way to target off plane lesions, which is really hard to do with a free hand, specifically if your lesions are in a very tight spot all the way up in the dome of the liver next to the diaphragm, for example.

So you have the sensor that goes into a sheath stylet and this is, not sterile, but you can read it all the time. But the sheath is sterile.

You remove the stylet and you dispose the stylet, you leave the sheath inside and through and through this sheath. You can do all your liver biopsies or any biopsy you're interested in.

So let's look an example of how to use this technology. So the thing is, you can either use it as I said with the V nav system or you can use the system on its own if you can tell or you see what you think is the abnormality in specific organ.

So here we have a patient who came jaundiced and got stented and there are this mass next to the stent. We don't know if it's a lymph node or it's a mass arising from the duct.

So again, ERCP brushing is negative. So we were asked to do a biopsy of this guy. And honestly speaking, if I really look at ultrasound on its own, how many of us can tell that there is something there?

The assumption is this may be part of the liver coming there because of the fissure going out there. So it's really, really not a good thing to just use the ultrasound.

But the CT definitely showing there is some soft tissue abnormality there. So we decide to use the e tracker system and you can see that we use the e tracker system, we put the needle there.

The graphical illustration on the image shows you where your needle tip the n the letter N identifies the tip of your needle. You don't see the needle most of the time so well, but as long as you keep your line here or your graph solid, the green, you know a hundred percent that you're going in the right spot.

So we placed this in the right spot and then through the sheath we put a 22 gauge needle and we did FNA. Of course you don't want a core in that area, but we were successful to get malignant cells most likely consistent with cholangiocarcinoma.

Again, as I said earlier, you can use this technology for multiple purposes. We already talked about the biopsies, but also we are trying to help our colleagues in radiation oncology for treating specific lesions in the liver.

This patient had a history of colon cancer. He is, he had resections in the past. He had multiple chemotherapies in the past and unfortunately he exhausted all his options for chemotherapy.

The only thing that is left for him is either resection or radiation. He was not fit for any surgical further surgical interventions.

So radiation oncology asked us to place a fiducial marker close to this lesion for purposes of treatment, radiation treatment.

So, what we do for our colleagues in radiation oncology is we try not to put the fiducial marker in the lesion itself. We try, they ask us to put it close to it or outside of the exact area of the lesion so that they can plan a larger field of radiation and treatment.

And that's what we did here. But look where this lesion is sitting all the way up in the dome of the liver. See this is the same plane, sagittal plane, almost coronal sagittal plane.

And how are you gonna get to that? You barely see it even on the ultrasound you see some area of hypoechogenicity there.

But we managed to use the e tracker system off plane and using a free hand technique depending on the e tracker. We put the trocar all the way up there and you can see the distortion of the anatomy from the ribs, the shadowing, and you can see the lung over there.

Despite all this limitation, as long as you have a clear visualization of your green line and the needle, the placement should be in the right spot.

So this is the lesion, this is where the fiducial marker close by and then we do a very, very limited CT scan to prove where we are after the procedure.

And we were successful for a good placement of that lesion for purposes of radiation treatment.

Conclusion

So in conclusion, I think I introduce you to a very interesting technology, which I think is gonna be the standard of how we are gonna be continue to do or implement ultrasound guided procedures before this technology.

Most of these cases that I've showed you, we would have to CT scan or we'd have just say no thank you, we can do it. So fusing imaging offers promise on multiple fronts, exact localization of subtle lesions that you don't even see with confidence using unique capabilities of the system as I showed you.

And it'll render difficult biopsies safer and easier. Again. The other point is you can characterize indeterminate lesions in patient who cannot undergo contrast CT or MR.

Like kidney cysts and could enable ultrasound to replace CT or MR for follow-up of selected lesions, reducing both cost and radiation exposure.

And thank you for your time.