Sonography of the Patient with Hepatitis and Cirrhosis - HD

Introduction

I am Dr. Hampi from Kick School of Medicine. I'm the chief of ultrasound and the department of Radiology. Today I'm gonna talk to you about the sonographic features in patients with hepatitis and cirrhosis.

Today our objectives is to describe the key sonographic findings of hepatitis and cirrhosis. We also gonna discuss the rationale of the sonographic evaluation of liver in the setting of chronic liver disease.

Now, whenever we talk about hepatitis and cirrhosis, of course this all goes under the spectrum of diffused liver disease. So we're gonna discuss how we're gonna do our exams and the technique we are implementing in our practice.

Imaging Technique

So the liver is best imaged with the patient in the supine and lift lateral decubitus position. You can place the patient first supine, look at the lift lobe of the liver in the sagal plane and image the liver in different planes, the right the left lobe, and look at the vascular anatomy as well.

So initially you should start with a three to seven megaherz curve linear array transducer.

Now, the recent development of a singular crystal transducers will give you a better resolution and ability to penetrate even deeper in the liver and have nice resolution and quality of the image that you are trying to get about liver pathology in diffused liver disease.

Liver Surface Evaluation

The other important thing in this discussion is to focus on one of the important aspects of the exam, which is always look at the liver surface.

Now we look at the liver surface using a high frequency probes. Now the higher the frequency with better penetration, as long as you can get that surface of the liver, you don't have to go deep enough. Just try to figure out the interface between the soft tissues, the TY plane and the capsule of the liver. Image that in the sagittal plane with the highest frequency that you have in your practice to get a better assessment of the liver surface.

Now it's very important when you evaluate the liver surface is to make sure that you either do this with video clips or real time examination. Otherwise, if you get some angulation of the transducer from the perpendicular to the liver surface, you may falsely simulate nodularity. Unfortunately, the fast positive findings will increase as you interpret your images based on still images. So real time is very important to evaluate the liver surface and avoid this pitfall.

Color Doppler Evaluation

In addition to that, you always should include color doppler evaluation of all your patients suspected of liver pathology.

Now this is very important, even if most of the exam, they're gonna come to you for evaluation of these patients with liver disease as right upper quadrant. Without doppler, you really don't have to have a doppler order by the clinicians because most of the clinicians in the practice, specifically primary care physicians, are not aware of specific doppler study requests for their patients. So the most common exams that they're gonna come your way and orders are gonna be apart, right upper quadrant.

Diffuse Liver Disease

Now, when we talk about diffuse liver disease, we have to discuss the following. First, we're gonna talk about hepatomegaly. We're gonna discuss hepatitis, we're gonna talk about ferry infiltration of the liver, and most importantly we're gonna discuss the appearances of the liver in cirrhotic patients. And at the end of this topic, we're gonna discuss the role of color doppler in evaluation of therapeutic port to systemic shuns.

Hepatomegaly

So let's start with heeg.

Now, the problem that we encounter in imaging as radiologists is whenever we deal with a 2D image, quantification of the size of organs is somehow difficult and inaccurate. We know that fact over many, many years. The only way to be able to establish correct measurements of organs in the abdomen like the liver, spleen, and the kidney, is to invest more time of doing volume measurements, which in practice may not be, practical thing for radiologist and can be time consuming.

So we believe that the most reliable measurement is probably the sagittal dimension from the dome to the tip of the right lobe. Now, you make your measurements along the ular line. If you do this and you found a measurement that exceeds 15.5 centimeter, the liver is probably enlarged.

Now it's very important to make into account that healthy individuals, specifically female patients, may have a variation of normal known as the AL'S lobe that can mimic hyperly. Hega can be confidently diagnosed when the liver extends caral to the right kidney and the left lobe is subjectively of normal size or larger.

Now the question here is we see there are some question marks here. The question mark here is about the same approach. How you gonna make that judgment in young females with rider's low? Now I use this in my practice and I apply it to the patients to male patients who are suspected of having an enlarged liver. Now your sensitivity may improve if you have abnormal liver enzymes or liver function tests.

Hepatitis

Okay, our next topic is to talk about hepatitis.

Now the thing is, in practice, most of the cases of hepatitis that we see is actually, if we talk about acute hepatitis, are those due to hepatitis A? Now, it's very rarely in practice to encounter patients with acute hepatitis B and acute hepatitis C. The thing is, these patients with hepatitis B and C in the acute phase, they really don't have specific symptoms and most of the time they experience some flu-like symptoms that go away. And we start to see these patients later in the disease when they have abnormal liver function tests or abnormal imaging findings of chronic liver disease.

So in the sitting of acute hepatitis, the most common ultrasound finding you would expect to see is most likely hepatomegaly.

Now, in addition to that, there are other findings that can help you come to the right diagnosis in the sitting in the right clinical setting IE that the clinicians are suspecting the patient is having an acute problem with their liver.

Now, striking irregular gbe wall as we see here and the sitting of acute hepatitis A alright, is a helpful sign. However, we need to be aware of the fact that this appearance can have a wide differential diagnosis. The wide differential diagnosis here would include patients with congestive heart failure, heart disease patients with other infectious inflammatory processes involving the gall bladder, et cetera. So it is not a straightforward, specific or sensitive sign. However, it may be a helpful features in the diagnosis of acute he hepatitis one point that really helps you pinpoint that the problem is related to to hepatitis rather than infectious, acute cholecystitis is to look at the lumen of the uh, goldbar air we can see on the next slides.

The other thing is if you review the literature, there's a lot of being described in the very, very early days of ultrasound about the staite liver pattern. Now I find this finding in practice confusing as many young individual with normal liver functions who do not have hepatitis, who come for other right upper for right upper quad ultrasound for other reasons have this pattern. So I don't think this parent is helpful and I find it again confusing and I think should be avoided in the process of interpretation these studies.

Now the other important thing is what else can be helpful in evaluating these patients? Now he parametria, as we talked about, can also be seen in chronic hepatitis. HEPA can be seen in chronic hepatitis before it progresses to its end stage liver disease, as we know it has cirrhotic change.

Now, the in homogeneous patchy or diffused increased echogenicity are quite common findings in patients with chronic hepatitis and are related to the amount of ferry infiltration that goes along with the fibrotic changes in these livers.

Now let's review some of the slides and the pictures in the video clips attached.

So this is a patient who presents with acute hepatitis A. We have abnormal labs confirming the diagnosis. But at the time of presentation you can see that the gover has a thick regular wall thickening and you can see how tiny is the residual lumen of the goldbar in this setting. Now, when you see this out of proportion thickening of the wall in compared to in comparison to the residual lumen, I think you should suspect acute hepatitis or any other causes of other than infection, inflammation of this appearance including congestive heart failure. You can also note that this patient doesn't have any gallstones. It doesn't mean that they may not have a calculus colon cystitis, but again, given this appear of the exuberant irregular thickening of the wall of the gbl, the diagnosis of acute hepatitis in the right clinical setting is the one to go for.

Now another patient with cirrhosis, as you can see here, there's cirrhotic liver morphology, there is a S surrounding the liver and you can look at the gallbladder. The patient is breathing and you can see or significant thickening in the wall of the gallbladder. In this instance, as part of the differential diagnosis, this thickening is most likely related to hyperemia associated with liver disease. This patient had an albumin level of less than 1.5, so you can tell that this is most likely the cause of this thickening.

Now a teaching point here is as series does not cause thickening of the gbra wall.

This next slide still image showing the prominence of the periportal fat, which is described as the starry night appearance seen in patients with hepatitis. But again, this individual or patient did not have any signs of acute hepatitis. The patient did not have any positive labs suggesting acute hepatitis. This patient was presenting for right upper quadrant pain for other reasons where the gbra was contracted. But this finding, I'm showing you this example in young patient with the prominent preport fat, which can be confusing and may give you the pattern of the study night falsely giving a diagnosis of acute hepatitis.

Fatty Infiltration of the Liver

We talk about diffuse liver disease, we have to really stop at this little important fact which is fairy liver or fairy infiltration of the liver.

Now, fairy infiltration of the liver results in enlargement of the liver with diffuse increased echogenicity. Now use the relative echogenicity of the kidneys, provided the kidneys are normal and compare it to the spleen. The normal spleen is slightly more echogenic than the normal liver ferry Infiltration is often patchy or focal.

Now a spared area in a ferry liver is usually hypoechoic. Now remember that whenever you see a focal hypo coic area on a background of a fairy liver, don't ever jump and say, well, there's a mass in the liver. We need to investigate further. The reason is, or the rationale behind this is if you are aware of the most common locations of the spared areas in fairy liver, like the dorsal to the gallbladder, anterior to the portal vein bifurcation, dorsal left lobe, the cardiac lobe and the sfor ligament is most likely is a benign process and does not need further evaluation.

So let's look at this video clip and see and understand the difference between the echogenicity of the kidney, spleen and the liver. You can see here that in some individual, when you're scanning the spleen, when the patient's is in the decubitus review right side down, you can see that sometimes the left lobe of the liver can migrate all the way to the left side of the abdomen and reach the spleen. Alright, this is what I call like a kissing spleen liver sign. The thing is, if you're not aware of this fact, you can think that there's a mass in the spleen or there's a mass in the liver or vice versa.

Now here you can see a good example of the normal echogenicity of the spleen, which is, should be brighter than that of the near liver. So this is a good way of comparison if you get both of them in the same plane. If you don't have them in the same plane, just take a video clip or a still image of the spleen, compare it to that of the liver on the right side when the patient is supine. That's also another way of doing this comparison, Harrison.

Now if we move on to the next slide, you can see here that we are managed in the same patient to get information about the echogenicity of the kidney and the spleen and the liver in one plane. Now it is unlikely that you're gonna see this in every patient in this spleen, but in this instance you can see that the spleen is brighter than the liver and the kidney cortex. Again, the kidney is a little bit maybe less than that to the liver or similar to that of the liver. That's what tells you that the liver echogenicity is normal and this is what you need to do and compare on the right side when you evaluate the echogenicity of the liver,

while both focal fair infiltration and focal sparing can simulate an neoplasm, an appreciation of the usual appearance and location sophists to avoid confusion. Now, this confusion can be averted if you supplement your study by color or power doppler. Look at the vascular structures cosing through that area of increased or decreased genicity. In other words, fair sparing or fair infiltration. If you don't see any splaying or distortion to the course of these vessels, means this is most likely a for focal ferry sparing or focal ferry infiltration depending on the echogenicity.

The other thing that you may encounter in practice while you evaluating the liver is geographic ferry infiltration. Now what does that mean means that either an entire lobe or entire segment are affected. Most of the time you would expect to see this involving the cardiac lobe. Sometimes you may see part of the right lobe, you may see multiple segments involved with the process. Again, the pattern can help distinguishing this appearance from neoplastic process. And again, color doppler comes to play an important role in this evaluation.

One important thing that you may help you supplement your confidence and sensitivity for diagnosis of early ferry infiltration of the liver is the use of spectral doppler evaluation in the hepatic veins. So normally you should expect to see a phasic hepatic wave form, which is a representation of opening closing of the tricuspid valve and the atrial contraction. Now in fair liver infiltration, you may lose a component of this or you may lose two components and the waveform becomes flat monophasic, or sometimes it may just be biphasic, which also should raise the suspicion for fairy infiltration.

So let's look at some examples of fairy liver spearing. You can see on this image that there's increased echogenicity of the liver, the level of the bifurcation of the portal vein. But in addition to that, you can see a stripe of hypo coic area without much of distortion to the vessels, which is most consistent with very sparing area in a common location. This is the same patient with more depth to appreciate this hypoechoic area here and here to the portal vein as previously described on the prior slide. And you can confidently call this ferry sparing area.

This is a nice example on this clip to show you a geographic RY changes in the liver. You can appreciate the normal echogenicity of the liver on the right side and the increased echogenicity consistent with fair infiltration. Now you need to be aware that sometimes large infiltrative masses in the liver can have similar appearance like that, including liver abscesses. But the clue again is what do you see on these images? You can see that the hepatic veins is cosing nicely through this part of the liver, no evidence of splaying displacement or mass effect or invasion. And you can see how nice the periportal fats and the triads of the biliary and arteries and, the bile ducts nicely depicted on this image, on this part of this, part of the normal liver.

Another example of a focal ferry infiltration. You can see the liver looks fine here, but this area in front of the portal vein is having or demonstrating increased echogenicity with some patchy areas of hypo echogenicity. The vessel cosing nicely through it, no distortion. This is most consistent with a focal ferry infiltration.

The good news about our experience with ultrasound of the liver is that, as I said earlier, focal ferry infiltration and focal fatty sparing, they follow the same pattern. In other words, wherever you see focal ferry infiltration or sparing, it's gonna be the same thing and vice versa.

Now, when we talk about fairy liver, we need to address a very important entity that has a significance and increased morbidity for patients if we don't make the right diagnosis. Now, this entity known as non-alcoholic stereo, hepatitis nash or non-alcoholic fairy liver disease is a condition where severe fairy infiltration needs to he ally and associated with inflammation and fibrosis. There's also associated increased abnormal liver enzymes, A-T-A-L-T in these patients and histologically NASH or non-alcoholic fairy liver disease, they resemble those of alcoholic hepatitis. In other words, if you have this histologic pattern observed on a biopsy on someone that has fairly liver, you have to be careful about the possibility of progression of the disease into a chronic liver disease. They may lead to cirrhotic changes, port hypertension and end stage liver disease with increased morbidity and mortality.

Now, can you make the diagnosis based on ultrasound? Absolutely not, but you can suggest the possibility of nash when you see severe high levels of increased diffused echogenicity affecting the liver. IE Whenever you see distortion of the normal biliary and vascular anatomy without appreciation of the pattern of these normal vessels in the liver, this entitles you to the possibility of nash. However, the diagnosis cannot be made by imaging and the only way to make the diagnosis is to do a needle biopsy because you need the histological diagnosis and staging of the disease.

Now in this example, we call this nash because this ferry liver is showing evidence of increased attenuation of sound through this ferry parenchyma significant loss of the normal architecture of the vascular and biliary three anatomy. And the reason why we call this nash is because this was biopsy proven otherwise. What we did say in your diagnosis that there is advanced degree of farry infiltration of the liver, a potential diagnosis like Nash should be considered in the differential diagnosis. Specifically, if you see abnormal liver function test like elevated enzymes, we move on.

Cirrhosis

We're gonna talk about cirrhosis. Cirrhosis represents changes related to chronic liver disease and progression into end stage liver disease.

Now, what would you expect to see in sera livers by ultrasound? What we look for is changes in the shape of the liver, parenchymal in homogeneity, and most importantly, nodularity of the liver, specifically at the surface.

Now, why is that important? It's important that sometimes if you don't pay attention to that subtle early surface nodularity, you may miss an early cirrhotic change. Now, surface nodularity may be the only sonographic sign of this early s cirrhotic change, and this may dictate more or advanced aggressive intervention by the clinicians to stop the progression or delay the progression of the disease.

Now surface nodularity is really specific for macro nodular cirrhotic change. If you see it, micro nodular changes are not really picked up by sonography, and most of the time the diagnosis is made by pathology IE on a biopsy.

Now what other features you would expect to see with cirrhosis? You would expect to see small right lobe with left and cardiac lobe hypertrophy. Once you see these findings, it's a straightforward diagnosis and most of the time you can see associated other features like as series and changes related to the portal vein that we're gonna talk about in few moments.

Let's start, let's look at some of the examples of, cirrhotic change. This is a high resolution ultrasound using a linear probe evaluating the lift lobe of the liver. Now this is a straightforward exam because look in the presence of a size, your specificity and sensitivity significantly improves. You can see how a regular this liver surface indicative of satic change in this patient with chronic hepatitis.

Another example, whenever you have a ses, you can really appreciate the nodularity of the surface, in the right and left lobe of the liver. And this is improved due to the fact that you are using the societies as a water window to improve your acoustic, signal and identifying this nodularity in the liver surface. But again, in the same instance, you look in this case, the patient has multiple, multiple hyper echoic lesions all the way through the liver that has been proven to be HCC and this patient with longstanding chronic hepatitis.

Another example of changes that you can identify in cirrhotic patients in addition to the nodularity of the surface that you can see here at the interface of the acidic fluid anteriorly is this, are these multiple hypoechoic scattered through the liver parenchyma and these hypoechoic collegiates scattered through the lunar cannot be, adequately characterized by sonography. However, all you can say is describe them and most likely they may represent region rating nodules, but, and h CCC among any of these could be a possibility. And further imaging with MRI may be helpful to better quantify these nodularity and these nodal lesions in this liver.

Now one important thing is whenever you look at the liver surface and you start to see some bumpy lumpy, nodularity on the surface with some mimics of masses, like in this instance, which is bigger than one 1.5 centimeter, you should include in your report that you are suspicious that this could be a dysplastic nodule. And further imaging with MR or multi-phase CT scan should be performed to exclude the possibility of HCC.

Color Doppler in Cirrhosis and Portal Hypertension

Now that we talked about the gray scale, findings in, cirrhosis and chronic liver disease, we move on to address one of the most important aspects of evaluating patients of cirrhosis, which is the role of color doppler sonography in this, population of patients with cirrhosis.

Now what do we look at is you need to look at everything. You need to look at the portal vein, you need to look at the hepatic arteries, you need to look at the presence of, venous salas in the abdomen. And, it's very important to be very meticulous in the evaluation of these vascular structures.

So now the most important thing we look for is we look at the portal vein and we try to establish whether there is reversal either complete or biphasic. In the portal vein, we look at the presence of collaterals in the left gastric, the para umbilical, all these suggesting the presence of portal hypertension.

Now, it's very important to keep in mind that, in a good percentage of patients without advanced and gray scale imaging, they may start to show these findings of portal hypertension, which is really important to include your color Doppler evaluation in every right upper quad ultrasound in patients known to have chronic liver disease.

So what are the findings that are expected? In addition to the portal vein findings, we always try to look at the HEPA arteries, the HEPA arteries. We look for a corkscrew pattern that is reflecting an enlarged arteries trying to compensate for the decreased flow of the portal venous flow. So this can be a good sign that will help you supplement your impression of underlying portal hypertension.

In addition to that and enlarged peric IES and the liver will show higher velocity. In other words, they have higher frequency shift and you can easily observe this on real time with aliasing patterns suggesting the increased blood flow to the, the increased arterial blood flow to the liver.

Now the next step you have to look for is you need to look at the hepatic veins, the hepatic veins evaluation, despite the fact that blood flow can still be preserved and going in the right direction outside of the liver into the IVC, you need to evaluate the pattern of the blood flow. Now, it's very important to make sure you don't miss the color evaluation of these veins to look again for aliasing. As a fact, we know that in the abdomen, the veins are not supposed to have color aliasing not supposed to have high frequency shifts unless there is stenosis in these veins. And this quite common thing in advanced liver disease and cirrhotic patients where due to fibrosis the, fibrotic tissue on both sides of the vein can compress the veins and create focal area of syno segment reflected as abnormal aliasing velocities.

In addition, spectral doppler evaluation of these hepatic veins will help you to supplement your findings, either increased velocities with loss of the normal phasic wave form. We talked about it earlier in the evaluation of ferry liver.

So let's review some of these images and video clips. So if you look at this, I really recommend that evaluating of this, physiology be performed in real time using video clips, or personally scanning the patient in real time to make sure you evaluate the, blood flow to the liver in the portal vein and the hepatic ery.

So in this instance or example, we can see that there is obviously biphasic portal venous flow going into and outside of the liver. Look at this changing color from red to blue. And in addition to that, you need to focus also on what's happening next door in the ies look, look how high velocity aliasing in these IES adjacent to the vein in this instance. So although we have partial reversal here, but we know that this patient is having, portal hypertension given the fact that the left hepatic ery in this instance is really enlarged and showing significant frequency shift IEA using which also supports the diagnosis of portal hypertension.

Now, other findings associated with portal hypertension and which really emphasizes the role of color doppler is the presence of this large paraumbilical vein going all the way out to the surface of the liver. Now the thing is, despite the size of this, because of the blooming of the color flow, because of the velocities that you observe here, if you don't apply color doppler over this FALs formm ligament, there's a good chance that you may miss the presence of this abnormality, which indicates that the patient is having hypertension.

Another example in this patient with a large paraumbilical vein, and you can see it's traced all the way to the abdominal wall and in this instance you can see it goes all the way north to the chest wall. Now remember that ized paraumbilical vein can e go north to the chest or can go all the way down and the pelvis and sometimes some of these patients may present with scrotal varie. So you need to know how to evaluate these patients and ask questions about if they have a history of chronic liver disease.

Another example here is we can see the other possibility of findings by color doppler in this instance. You can see on this video clip that there is reversal of blood flow, complete reversal blood flow in the portal vein. Now notice that the nearby HEPA ery shows some aliasing and its size is almost close to that of the portal vein, which is something you don't see in normal individual. Of course, in addition that see how heterogeneous the liver parenchyma the nodularity adjacent at the surface associated with these findings. All this will fit in the diagnosis of cirrhosis with portal hypertension.

Now if you notice here also that you need to pay attention that sometimes whenever you do evaluation of the portal veins with colored doppler, you may pick just partial reversal overflow in the mid-segment branch, as in this instance, this patient had a history of hepatitis secondary to ETOH alcoholic hepatitis and subsequent cirrhotic change.

Now, as I said earlier, we need to pay attention to these big hepatic arteries, the hepatic artery in this instance, the lift and its branches into the lift lobe show evidence of significant color aliasing, which indicates enlargement and suggesting increased arterial flow to compensate for the diminished portal venous flow going into the liver.

Another interesting thing that you can identify as I, we said, as I said with color doppler as you can identify the venous collaterals. And in this instance this patient was referred for evaluation of pret tips. Alright, so the request was pret tips evaluation. So the plan was is to create an interventional suite, tips in this patient, but while evaluating this patient, we managed to identify that the portal vein going into the liver shunting into the hepatic veins coming back out into the IVC. So you managed here to avert the possibility for an interventionalist radiologist to go and create the shunt as the patient is already having an or shunt what I call or shunt in this patient. And there's no need to intervene to decompress the system, it's already spontaneously decompressed. So expect to see these things occasionally in patients with, chronic liver disease portal hypertension and cirrhosis.

Now the question is if you evaluate the S liver just with the gray scale without color doppler, you are definitely gonna miss this significant finding in these patients.

Another example of changes encountered with color doppler in cirrhotic patients, as in this instance, you can see how the hepatic artery is big tortuous, and this is what we called it the cork screw artery. That tells you that there's definitely significant increase in the arterial flow into the liver. Now this is really a very good sign to suggest that there's going on some disruption to the portal flow to the liver because even though you can see still that there is everything is flowing in the right direction in the portal vein nearby this large ery suggests that there's not enough portal blood is going into the liver. You can notice here how sluggish this flow in the portal vein here adjacent to the artery.

Again, another example showing, despite the fact that the portal flow is still preserved hepato petal in IE going in the right direction. But you can see that this, color map and hue is so dark indicating sluggish flow. Addition to that, look at the arteries we talked about. Again, another example to emphasize this fact is the color aliasing, the turbulence, the frequency shift indicating increased arterial flow to this liver with diminished portal venous flow.

Other things that you may encounter in evaluating these patients, if you don't use color doppler, which obviously you can miss because you can assume all these things on a great scale, maybe bowel loops and you easily can miss that. But once you flick that color doppler and look at it and it's all filling going back and forth in different directions, the typical appearance of sub hepatic venous s sc secondary to advanced degree of portal hypertension secondary to s cirrhotic changes in the liver.

Now this is a nice example showing that if you have the right settings, you can identify esophageal vari as in this example with color doppler as well. Now without color doppler, there's no way you'll be able to identify that there's no way you're gonna tell what is there present or not, because this thing will be only identified by color doppler. So the teaching point, again, here is a repetition advice that you need to do color doppler on these patients with liver cirrhosis, even if they just present from the ED or from the primary care physicians or even hepatologist for right upper quadrant ultrasound, not requesting doppler evaluation.

Another example of cos. So here we are trying to show another spectrum of the venous cos that you can identify which easily can be missed if you just do gray scale imaging. So this hypoechoic thing adjacent or anterior to the left kidney in this instance would've been thought as maybe part of the normal perinephric fat. However, when you, evaluate this with color double, you can see a very large venous, collateral, in the left flank of the abdomen suggesting port hypertension.

Therapeutic Portosystemic Shunts

All right, so, now we gonna talk about, therapeutic portosystemic shunts in these patients with the cirrhotic, changes. And you can say that we evaluate those portosystemic shunts, every now and then to make sure that they are, patent and functioning.

And the most important thing that you need to keep in mind is try to avoid evaluating these shunts immediately after being put in. The reason why is most of these are covered stents and these cover stents will have trapped nitrogen air, at the time of the, placement and procedures that are still not absorbed by, by the patient and, may, mimic or simulate complete thrombosis as ultrasound have, a difficult, difficulty penetrating through air and, will significantly diminish the accuracy of, your study and erroneously will definitely give wrong diagnosis at that point. So the advice is try to, not evaluate those, prior to 48 to 72 hours from the time that they were put in.

So what do you use to evaluate these steps? We know that low frequency doppler right about two three megahertz will be best for imaging these tips. The reason why they're gonna be deep in the liver and the only way to get to this appropriately is via intercostal approach.

Now, the tip stenosis alright, may result in increased or decreased flow velocities. Now there's a big variation in the literature about what is normal, what is abnormal, but I think generally accepted rule is if your velocity is between 90 and 200 centimeter per second in the mid and this stint, then the tips is most likely patent and open a fairly specific but insensitive parameter of stent dysfunction is finding flow away from the stent in the native portal veins. But again, if you see preserved hepato petal flow specifically in the left portal vein, it doesn't mean that the stint is not functioning. In other words, if you see the reversal in that vein because of the presence of the stent stent, this will support the fact that the stent is functioning and open at that point.

So let's look at some examples. This is a stent evaluation with color and specular wave doppler. You can see in part of the stent we have nice velocity coming here and then we start to have, see some increased velocities with color aliasing and frequency shift, and we measure the velocity and it's 268 centimeter per second. So this suggests that this is amid stent stenosis.

Alright, another example of, tips, evaluation with color doppler. And this is the most reliable finding to say that the tips is thrombo is when you do not see, flow within the stent by color doppler. And this is, in my experience, I find this as a very reliable sign that the tips is not functioning, but also you have to be aware of the fact that you need to have optimized color doppler ceilings before you make this call. And also it's worthwhile evaluating the stent with power doppler because power doppler is more sensitive to sluggish flow. And if you see the same thing by both, most likely this steps is thrombose. Additional thing is some vendors have, something called B flow imaging that can also be sensitive for evaluating of these steps and can also improve the confidence of making the right diagnosis about thrombosis.

This video clip here shows a similar pattern of, aliasing in the mid stent with narrowed part of the stent here. And this also consistent with, med stent stenosis. In other words, video clips can help or real time imaging with a specker wave doppler which complement each other and help you make the right diagnosis as well about these, stents in the liver.

As I said earlier, you can use power doppler in the evaluation and stent, and this is a very nice example of a tight stenosis in the mid stent here, secondary to a peripheral clot, there's creeping to the mid of the stent and resulting in malfunctioning of the stent.

A common problem with the, the tip stent is over time the stents can migrate backwards into the hepatic vein. You would like to have the stent, on this, subcostal image just coming into the IVC not, really extending further, to the back of the IVC just a little bit here. And usually in this example here, as you see is like it retracted all the way back into this hepatic vein. And this of course needs to be fixed, but if you apply color doppler, as we can see on the nest example here, you can see how nice flow is coming down the jet. And there's a jet phenomenon with aliasing coming through the narrow segment of the hepatic vein where the stent retracted, suggesting that this is, post stent stenosis.

Advanced Techniques in Diffuse Liver Disease

Now, we need to address some of the findings, some of the new applications that are being implemented, in the evaluation of diffused liver disease, ultrasound contrast material as being, studied quite, extensively, in, in Europe and Asia, something in Canada, something we don't have access to here in the United States. And, we, cannot, comment much about our experience here, but something that we expect to happen in the near future.

The other thing is, other, software manipulation like 3D evaluation of the liver surface, in cirrhotic patients. This, technique is best utilized in the presence of a series. It really does not work without the presence of asci. It has too much limitations. So if you have enoughs, it can be helpful. We can see some examples.

Now the other thing is other software, applications like pic, a reduction imaging, which really is post-processing of application of different livers of compounding can improve conspicuity of diffused liver, disease and, evaluation of subtle nodularity as well as focal lesion in these cirrhotic patients.

And now, this is, and we move on to elastography. This is, something that is gaining popularity in, in the industry in Europe, Asia, the United States. Now a lot of application and studies being done extensively in Europe, not much in the United States. And of course, speed of sound manipulations, where, people identify that if you improve, manipulate the, the, if you manipulate the ultrasound, speed of sound, you can get better evaluation of fairy livers. Some limited experience, so far in the literature.

So let's take some, take a look at some of the examples. This is a 3D liver surface, and you can see how nice the, the nodularity of the liver is nicely appreciated. But again, to be able to do this, you need, a lot of fluids surrounding the liver to get nice images. If you don't have that, it's really hard to appreciate the nodularity. And as I said earlier, high risk 2D image, should be, enough to make, the diagnosis of surface nodularity.

Now, this topic is beyond, the discussion of an histography, but, in brief you are using mechanical force induced tissue, external or internal force. You measure the tissue displacement with either ultrasound or, or mr. And of course, what we're trying to do here is trying to, estimate, the tissue stiffness, qualitative or quantitative. Basically what we're trying to do in the liver is, assessment of liver fibrosis. It, based on the data published, in Europe, it's, and, and, and the United States, it sounds like that there's a future for evaluating of, the degree of liver fibrosis. Unfortunately, quantification of masses as benign versus malignant, and the liver is quite limited and there's not enough data to, support its use.

So this is an example of, in ethnography what you do is you, pick a region of interest and you identify that region of interest. And based on the scale that you identify here, it'll tell you how stiff the liver, the, the liver parenchyma, and whether it's soft or stiff, depending on whether the patient is having fibrosis or fibrotic changes in the liver. And you can see here there's examples. This is examples from studies done in Europe, quantifying the biopsy score and, the correlation of the finding of the degree of, fibrosis in the liver.

Now the system will give you or measure the speed of sound and actually will also estimate for you the degree of stiffness based on the kilopascal measurements. And, this is a very intriguing way and a very promising technique. It has been, improved in, multiple, countries in, Europe as evaluation of the degree of fibrosis and potentially avoiding an invasive procedure like, fibrosis, like, biopsy.

So, this is, the fibrotic score that, everybody is using now in, in the degree of, pathology, quantification of, the degree of damage in the liver. And you can know it goes from zero to four. And of course, four is cirrhotic change. And the whole point of this evaluation is tried to, hold the progression of disease when it's at this stage between F two and, and f three.

Conclusion

In conclusion, as you can see, ultrasound is an excellent tool for the evaluation of diffused liver disease. It still has unprecedented advantage of real time imaging, particularly blood flow dynamics, which gives ultrasound the advantage over CT and MRI. And thank you for your time.