Sonography of the Appendix - SD

Introduction

I am Cindy Rat from Denver, Colorado.

Today I am gonna be speaking about sonography of the appendix.

Normal Appendix Imaging

Looking at the long axis of the appendix, it would be great if all the appendix cases would look like this where we have the cecum and then you can see the normal appendix coming off and diving deep here over the iliac vessel.

When you're imaging the appendix, you wanna make sure that you do scan in two planes, so a short axis view of the appendix looks more like a target lesion and it would be graded when we were scanning. It would be this easy to see.

Also, notice that this appendix is only one centimeter beneath the skin surface and scanning.

It's reported that the normal appendix is only seen approximately two to 10% of the time when evaluating the right lower quadrant for pain. In our experience, we have increased by looking and using a systematic approach when we scan for the appendix.

So what we will talk about is the systematic approach that we use in trying to locate the normal appendix.

Characteristics of the Normal Appendix

Looking at the normal appendix, it should be six millimeters or less in AP diameter and that's measuring an anterior to posterior diameter. We'll show an example of this in a second.

It should be partially compressible. So when using graded compression with the transducer, you should see the appendix will compress somewhat.

You will not see peristalsis inside the appendix. If you see peristalsis in the appendix, typically what you're going to be doing or what you're going to see is possibly some air that is moving. But if a structure is peristalsing, you're typically looking at small bowel, but we will not see peristalsis in the normal appendix.

It is key to make sure that you do visualize this in two scan planes. What can happen is you can take a loop of small bowel and by compressing you can make it look just like the long axis view of a normal appendix. But when you rotate your transducer 90 degrees, you'll not get the target lesion. Only the appendix will give you that target lesion.

So it is key to make sure you do scan in two planes.

Measurement of the Appendix

This is looking at how not to measure if somebody was just looking at the measurements. You see that we have a measurement here of almost eight millimeters and that's because the first caliper was measured across the width of the appendix. We only wanna measure an anterior to posterior diameter and you can see that this normal appendix only measures about four millimeters.

Here's exactly how you wanna measure another normal appendix. That is four millimeters in a short axis view and you can see it's much easier to measure in the target view I think, than it is in the long axis view.

Sonographic Layers of the Normal Appendix

Looking at the normal anatomy of the appendix, there are three layers that we can see sonographic. The first is going to be the echogenic lumen. So when the lumen is collapsed, you'll see just a very thin slit right across here that is the collapsed lumen.

There's then a muscular wall that is more hypo surrounding it and the outer layer of the appendix or the CISO layer is an echogenic layer that we can see surrounding it.

Actually there are five layers of the normal appendix and typically we don't see all five layers, but with our higher resolution equipment. Now occasionally you may see these five layers and you can see that these are the different layers and approximately the measurements of them.

Main thing is when you're measuring the appendix, make sure that you measure from the outer mors echogenic layer from one side to the other. And occasionally we will see these five layers.

If you want to see how birds see the world, everything looks like a target lesion. That is also what we're looking for in ultrasound.

This is a short axis view of an inflamed appendix. You can see you don't see the echogenic lumen. There's distinction of it, but this is a short axis view of appendicitis.

Variations in Appendix Location

Now looking at this netter illustration, you can see all the variations of where the normal appendix can be located. I've actually never seen one yet on the left side, but I suppose if a patient had sitis inverses, we could at times I have found the appendix clear up by the gallbladder and we have seen the normal appendix also on endo, endo vaginal sonography adjacent to the ovary.

A lot of times the appendix can be retrocecal. The most common location is for the appendix to come off and head medial across this way.

So here's looking at normal variations. This is a case of appendicitis that we see all clear up by the tip of the liver. This is another example of appendicitis that we found on an endo vaginal ultrasound exam.

So just showing you some of the variations that we can see the appendix and talking about the technique.

Scanning Technique

You wanna use a high frequency linear array transducer and even on patients that are fairly heavy, I'll at least start out with a high frequency probe. And the second half of this lecture we're going to actually talk about inflamed appendix and you'll see the importance of using the higher frequency transducer and looking at that.

If I need to switch to a lower frequency transducer for better penetration, I actually prefer going to a curved array transducer rather than the linear array just because I get a wider field of view.

That way we then are going to use a systematic approach. And the key to finding I think appendix is to use graded compression. So you don't wanna take the transducer and just bear down, but gradually add more and more pressure.

The more that you can compress the top layer of the skin up against the muscles in the deep abdomen, you're going to have a much easier time in finding the normal appendix.

So these are the scanning strategies of how we go about locating where the appendix might be. First thing is we wanna identify the SE L tip. We will look for the appendix draping over the iliac vessels and I'll go over each of these individually.

We will look posterior to the terminal ileum. If we don't find the normal appendix, we'll go back and look anterior to the iliac as muscle. We'll look behind the cecum. I think a retrocecal appendix is a place that we miss a lot of our cases of appendicitis and then at times we'll look deep in the pelvis.

These tend to be more common locations on females that we'll see the actual appendix deep inside the the pelvic area.

Identifying the Cecum Tip

So the first thing we're gonna do, how do we identify the SE L tip in location? It's gonna be the most lateral structure that we're going to be scanning in the abdomen. If you look at the size of it, it's larger than small bowel.

And when we look at the gas pattern, we're gonna look for what's called a bumpy gas pattern when identifying the the cecum versus a smooth gas pattern.

So if we look at this netter illustration, you can see that the colon comes down, this is your SQL tip, your terminal ileum is coming in here and then this is where the normal appendix is gonna come off and kind of head in a medial approach looking at the seum.

So when we talk about a bumpy gas pattern in the secum, since it's part of the colon, air gets trapped be between the semi-solid contents within the colon versus if you're looking at a smooth gas pattern, if you see gas that is layering on the anterior surface, this typically is small bowel.

So what we're noticing is air rising to the top of more of the fluid that we'll see within small bowel versus the bumpy gas pattern of the colon.

What I'll start doing is scanning in a transverse plane and follow the bumpy gas all the way down until it ends. And then once it ends we know that we're at the area of the SQL tip.

So once again, I start transverse about the level of the appendix or I'm sorry of the umbilicus or maybe a little bit lower scan down until you see the bumpy gas in. Come back up. And then what we're looking for if you're scanning in a transverse plane, that will be long axis of the normal appendix when you're scanning longitudinal on the patient.

This will be more of a short access view of the appendix.

A variation of what we can see with the appendix seql tip. Or looking at the tip of the cecum is where we have what's called a persistent fetal appendix. If I were to measure the appendix at this location, it would probably be greater than six millimeters, but this is just a normal variation as long as the appendix tapers distally.

It is something that you may see occasionally is that persistent fetal appendix.

Locating Appendix Draping Over Iliac Vessels

So once I've identified where the seql tip is, if I haven't seen the normal appendix arising from it, then what I'm gonna do is look for it draping over the iliac vessels. I wanna orient my transducer parallel to the vessels.

This tends to be more common in thin women and children that will see the appendix in this location. And what's difficult is the mid portion of the appendix will be anterior to the vessels, but the distal tip of the appendix will sort of dive into the pelvis.

And it's very important in evaluating cases for appendicitis that we do evaluate the entire length of the appendix and we'll talk about that about segmental appendicitis in a little bit.

But here you can see when you orient longitudinal or long axis to the vessels, you're going to have a short axis view of the appendix. When you are transverse on the vessels, you typically are going to have a long axis view of the appendix and you can see how the tip could dive deep into the pelvis and be more difficult to look at.

Locating Appendix Posterior to Terminal Ileum

So once we've oriented to the vessels and we still don't find the appendix, what we'll do is go back up, locate the terminal ileum and see if we can find the appendix just posterior to that how we locate the terminal ileum.

It's going to be medial to the secum, it's smaller than the secum and within the terminal ileum, you're going to notice more of that smooth gas pattern. You will see peristalsis within the terminal ileum and if you can I identify the ileocecal valve, then you're going to be certain that you're dealing with the ti.

So this is what the ileocecal valve look like on sonography. It's not something that we look for all the time. I've got a picture of it here, but most of the time we really don't evaluate the ileocecal valve.

So in scanning this, if this was a video clip, you would see that this loop of small bowel was peristalsing.

Here's a short axis view of the normal appendix. You could see the collapsed lumen, the muscularis and the ciero layer just posterior to the terminal ileum.

Locating Appendix Anterior to Iliacus Muscle

Once we've looked in that area, we've still not located the normal appendix. We'll look anterior to the iliacs muscle. This tends to be more common in children and males that we will see that.

So when you scan over the iliacs muscle, here's a short axis view of the appendix and then right adjacent to it. We once again, if this was a cine loop, you would see this loop of small bowel that was peristalsing rotating our transducer 90 degrees.

Here you can see the muscle and the normal appendix extending all the way across the anterior surface of that muscle.

And here is a short axis view of a normal appendix anterior to the iliacs muscle in scanning this patient.

Locating Retrocecal Appendix

So we still haven't located the appendix. What we'll do is go back up to the cecum and as I mentioned earlier, this is sort of a difficult area to find the normal appendix. I have not seen a normal retrocecal appendix yet. I have diagnosed cases of appendicitis that are retrocecal.

Occasionally the appendix can be lateral to the secum. So you wanna make sure that you look not only medial but scan lateral to it and rolling the patient up into a decubitus position may be helpful to look for appendix, it possibly could be retrocecal, but I think in a lot of cases where we miss the cases of appendicitis, it's due to it being a retrocecal appendix.

Now this is a patient that we scanned. You can see this is an appendix that is actually lateral to the secum. I don't have my transducer backwards, but this is the seum and instead of coming off and heading medial, this person's appendix came off lateral.

This is a case of appendicitis that is retrocecal. You can see all the edema that we see within the secum, but retrocecal appendicitis.

And this is also that same case of long axis views, a short axis view of the appendix that was lateral to the normal seum.

Locating Appendix in the Pelvis

Next we'll go in and check in the pelvic area. As I mentioned earlier, it's common in females. We have actually seen multiple times cases of appendicitis on endo vaginal sonography, but I have not yet seen a normal appendix on an endo vaginal ultrasound exam.

This is a patient that we were scanning, came in with right lower quadrant pain. We saw that she did have a cyst on her ovary and at first assumed that that was the cause of her pain. But sitting between the uterus and the ovary, we saw this area elongated it.

It did come to a blunt end, went back up and checked transabdominally and this is a case of appendicitis that we found on endo vaginal sonography. You can see the layering of the pus in here and then just fluid within the appendix.

But this is a case of endo vaginal appendicitis.

Segmental Appendicitis

Segmental appendicitis. As I mentioned, it's very important to make sure you scan the entire length of the appendix. What we'll see is that the proximal portion of the appendix is normal, but the fundus or the tip of it is what is enlarged.

So if we cannot identify the fundus, we basically have to consider the exam as being incomplete or non visualized.

So here's just a diagram of what it will look like. A normal appendix, this would be the cecum and a normal appendix. You wanna make sure that you can scan it and see all the way to the fundal tip.

What I try and do is scan in a short axis view and follow that. So in other words, you have the appendix looking like a target lesion, follow it all the way until all of a sudden the target lesion disappears. And that way you know that's the fundus.

Then rotate your transducer 90 degrees and get a long access view of the appendix that looks similar to this.

If we're talking about segmental appendicitis, what happens is from the point that the appendix becomes obstructed distally is where we're going to see the inflammation.

Now if you misdiagnosis in somebody, probably what will happen is the patient will come back a day or two later and this will be full-blown appendicitis where the entire appendix will now be inflamed.

But segmental is just seeing the distal portion of the appendix being abnormal.

Looking at this patient, you can see that the proximal portion measures five millimeters and appears to be normal. We even can see the collapsed lumen through this portion of the appendix and then we can see here's an append width and the distal fundal portion of it is 11 millimeters in measurement.

So you can see the difference with segmental appendicitis on this particular patient.

Length of the Normal Appendix

A lot of people will ask me what the length of the normal appendix is and my answer to that is we're all as unique on the inside as we are the outside.

So scanning this patient looking at this long axis view of the appendix, this could look like it's the fundal tip of it, but if you were to scan this in short axis view, you would see that the appendix would continue on and you could see the distal end of this appendix here is an appendic lit and you can see distension of lumen.

There's pus and fluid within this. This patient had a very long appendix. So there's really not an answer as to how long the appendix can be.

This was placing basically, you know, two different segments of the appendix and I've seen some cases of appendix that that you know are just about four or five millimeters long and others that will go or I'm sorry, four or five centimeters long and others that'll extend much longer.

So there's not really an answer as to how long the normal appendix. What we're more interested in is measuring the AP diameter.

Prevalence of Segmental Appendicitis

When we're looking at cases of appendicitis, we did a study in our department looking at segmental appendix and in children we found it approximately 21% of the time in adults about 16% of the time overall approximately 19% of the time.

So you can see that it is something that you wanna make sure you scan all the way to the end the distal end to make sure that you don't have a case of segmental appendicitis.

Air Within the Appendix

Looking at air within the appendix, air within the appendix actually acts as almost a contrast agent and helps to identify where the appendix is.

Now in scanning this, this looks like the image I had showed you earlier of the small bowel where we get the smooth gas pattern. But when you rotate your transducer 90 degrees on this and you get one little bright echogenic line, there's only one thing that can cause that and that is the appendix.

So you can see air within the normal appendix and then when you rotate the transducer 90 degrees and you just get that one little dot, that's only the appendix that would show that if this were small bowel when you rotated your transducer 90 degrees, both views would look like this with the ring down.

What I have seen is in using compression sometimes being able to move that gas back and forth and that's why sometimes you may hear people say that they have seen peristalsis within the appendix, but it's just the normal gas within there.

Now gas can be also caused by an abscess. And so a little bit later I'll show you how you tell the difference between normal air inside the appendix versus a appendix with air due to inflammation.

Here's just another example. You can see the proximal portion of this appendix, it's only three millimeters in size and then the distal portion is filled with air.

So just a normal finding that we can see is air within the appendix.

Prevalence of Appendicitis by Age and Gender

And also in that same study that we did looking at the appendix and segmental appendicitis, we looked at the prevalence of appendicitis by age group and gender.

You can see that when females come in with right lower quadrant pain, we find appendicitis not as often as we do in males, especially when the females are around 13 to 16 years of age, there's only about 10% of the time that it was actually appendicitis causing their pain.

Whereas if you have a male come in with right lower quadrant pain, you can see the percentage of time that there's actually appendicitis that was diagnosed. And in also in these teenage males it was 63% of the time so much more prevalent in males with right lower quadrant pain than it is females.

Conclusions on Normal Appendix

So conclusion, in looking at the normal appendix, we can identify it with greater frequency than was previously reported. When we use a systematic approach, success rate is higher and improvement of negative predictive value is greater in children than it was in adults.

In the study we did, a lot of times when we get the young children that come in, you can see this is a 13-year-old female presented with right lower quadrant pain, we found this cyst on her ovary. It is still important to try and locate the normal appendix to make sure it's not appendicitis causing it.

And in scanning this patient we can see here's a long axis view of the normal appendix rotating the transducer. You can see here's a short axis view, a couple different little areas of normal air within that.

But on this 13-year-old female we're able to prove that her appendix was normal and the cause of her right lower quadrant was due to an ovarian cyst that she did have.

Acute Appendicitis

Now looking at acute appendicitis, it is the most common surgical abdominal emergency in North America. About 30% of the time the patient's symptoms and signs and the lab findings are atypical.

Now a lot of times is already mentioned when patients or females come in with right lower quadrant pain. More often we're going to find something like this, a hemorrhagic ovarian cyst that is causing their pain rather than appendicitis.

It'd be wonderful if all cases of appendicitis look like this. You can see this as one centimeter underneath the skin. Here we can see all this edema and swelling of the secum. Here's the appendix coming off.

We have an app pentacle with here you can see distinction of the lumen. There's some fluid within here. We can see that there's abscess within that, but it would be wonderful of all cases of appendicitis where this easy to identify.

You can see this is the same case, a gray scale image of it. Here's the app, pentacle lift and distension of the lumen.

You can also use colored doppler and look at the inflammatory hyperemia.

Now the key to diagnosing appendicitis is what we like to call thyroid in the belly. And if you look at this area surrounding the appendix, this is just edema of the normal fat that surrounds the appendix.

If we look at CT findings, what they're looking for is that stranding of the fat and we can see the same thing on ultrasound.

So when I actually look for cases of appendicitis, what I'm looking for is that echogenic fat or also what we call the thyroid in the belly.

You can see hyperemia within the appendix. It's not something we look for all the time, but if you do see increased blood flow, typically it is going to be low velocity flow. You may see some pulsatile venous flow within it, but that is something that we will see with the inflammatory appendix.

Here you can see scanning the cecum in a long axis view. You can just see distension of the lumen through here and look at all the edema that we can see within that seql tip.

Short axis view of the secum, you can also see all the edema that we see from the inflammation of appendicitis.

Differential Diagnosis: Mesenteric Lymphadenitis

This is a 10-year-old male patient that came in with right lower quadrant pain and in scanning the right right lower quadrant we could see that he had enlarged lymph nodes.

Now you can get mesenteric lymphadenitis that we see quite frequently in these children that come in with right lower quadrant pain but also appendicitis can cause the lymph nodes to enlarge.

So what's very key on these patients is to scan and try and find the appendix. And on this young man we're able to find that he did have a normal appendix and the lymph nodes what we he actually had was diagnosed with mesenteric lymphadenitis.

So that just a viral infection, the patient will get well on their own, no surgery is needed.

So ke ultrasound is locating the normal appendix. I proving that it's not appendicitis causing the lymph nodes to enlarge.

Challenges in Obese Patients

This is a patient that as we call has on their winter coat. You can see even before we get to the area of the inflammation, we're already at about four centimeters, three to four centimeters in depth.

Sort of a key to remember when you're using your high frequency linear array transducer for any type of imaging, when you're trying to look at a structure deeper than three centimeters in depth, you're starting to push that transducer too far.

So when I started scanning this patient with a high frequency linear array, I noticed that I just saw this fuzziness deep in the image. And then as I mentioned earlier, what I like to do when I switch to a lower frequency transducer is to actually go to a curved array because you get a wider field of view.

You can see there's just this big fluid collection and a lot of edema going on.

There's a lot of different inflammatory processes that can cause this thyroid in the belly type of appearance. But in scanning around, what we're able to do is find what appeared to be in normal appendix and this is appendix that has perforated and compressed and then we have this big flagman or this fluid collection deep in the right lower quadrant.

So what will happen is once the appendix ruptures and all of the fluid or the inflammation is outside of it, it will decompress and a lot of times return back to what appears almost to be a normal size.

Resolving Appendicitis

Appendicitis can also resolve this is a patient that the appendix was enlarged, we followed them up. You can actually see that there's dis distinc of the lumen, some pus in here and this appendix only measures six millimeters.

We followed her up and it returned back to a normal size. So we have seen cases of appendicitis that resolved as long as they do not have an appendic with obstructing the appendix.

You can see there was still some hyperemia within this appendix on color doppler in the short axis view.

Retrocecal Appendicitis

This retrocecal case of appendicitis here you can see the secum disti of that but look behind the secum. This was the key to diagnosing this case of retrocecal appendix is all this thyroid in the belly and if you look right in the middle of this echogenic fat, this is where we see the retrocecal appendicitis.

There's also increased blood flow when we look on power doppler and pulse doppler. Looking at this case of retrocecal appendicitis.

Sonographic Diagnosis of Appendicitis

So sonographic diagnosis of appendicitis in patients with right lower quadrant pain. What we look for is a non-compressible appendix. I put here seven millimeters or greater.

And you're saying well wait Cindy, earlier you said the normal appendix was six millimeters. The key that I wanna make is once again as already mentioned, we're all as unique on the inside as we are the outside and I don't like to use just a certain number.

You wanna put the whole clinical picture together. Typically the normal appendix only is going to measure about three to four millimeters in size. But I've seen normal appendix that measures up to about eight millimeters.

Patient was non-tender. Over the appendix it measured eight millimeters in size. There was no hyperemia within it.

So I want to just sort of remind everybody that you don't wanna always stick to a certain measurement that there is variation within that.

If you see the presence of an append lith that is abnormal edema of the me appendix and fat surrounding it is I think the key to the diagnosing of acute appendicitis.

And you can use colored doppler and look for the presence of hyperemia or increased blood flow.

So looking at this long axis and short axis view of a case of appendicitis and once again I want you to know us the thyroid in the belly or the edema surrounding this. This is the meso appendix coming off here.

Now the a meso appendix is just sort of a little layer that attaches the appendix to the cecum so that we can see inflammation within that also. But that is the meso appendix attaching it.

This is a long axis view of a case that we did several years ago. In fact, this is from the good old days of annular array technology. But also you can see that the case of appendicitis is about three to four centimeters in depth.

Here you can see a edema of the cecum. Here's an appendic lit the appendix diving deep. When we image deep into the tip of the appendix, you can see that there's a second append lift here but also notice all this edema of the fat that we can see surrounding the appendix.

And this is the meso appendix right here that attaches the appendix to the SQL tip looking at a short axis view with and without compression. And you can just see that we do not have any compression of the appendix, but I think it would be quite obvious that a case like this you will not get any compression in short axis view of cases of acute appendicitis.

Here's the inflamed appendix. You can see dis distinc of the lumen, some pus that's located in here, but look at what you know almost looks like a donut surrounding it. And this is just a edema of the fat surrounding the short axis view.

Here we can see a little bit of blood flow in the outer layer or the serosal layer of the case of acute appendicitis.

Now even if the appendix becomes gangrenous and avascular, you can still pick up hyperemia within the meso appendix. So sometimes you won't always see increased blood flow within the appendix. It can become gangrene neovascular.

But you will pick up blood flow within the me appendix and you can see that low velocity flow that we see within this case of hyperemia of the meso appendix.

Pitfalls in Diagnosis

False Negatives

What are some pitfalls that can lead to diagnosis of false negative segmental appendicitis is one of them having a patient with retrocecal appendix. If you have a gangrenous or a perforated appendix and you assume that it's normal air within the appendix, you mistake it and also lead a markedly enlarged appendix.

So the first thing looking at segmental appendicitis, we've already talked about this but it's something very important. Make sure that you scan to the distal end of the appendix Segmental appendicitis is when the proximal portion is normal and make sure you do see that distal.

So looking here you can see the body of the appendix is normal here the fundus is just abnormal. So a small case of segmental appendicitis.

Retrocecal appendix is we already mentioned it's difficult to visualize as I talked about, rolling the patient up into sort of a decubitus approach or rolling 'em up on their side and try and come in behind the cecum can be helpful in locating cases of retrocecal appendicitis.

Here was a case that we had of a patient with retrocecal appendicitis. You can see that the appendic or the seum is inflamed. Here is the appendix that is retrocecal but very difficult to identify.

Typically what we look for once again is that a deus fat that is behind the secum and looking at a gangrenous or perforated appendix. What will happen is you'll lose the echogenic submucosal ring and what we're looking for is more of an inflammatory mass or abscess that we'll see within this.

So in scanning this patient when we put the transducer down, we found what I like to call a big goba where you're like what on earth is going on here? But you can see just all of this inflammation that we can see within it and scanning around we're actually able to find what looked like a short axis view of a normal appendix.

But here is the append width and this is appendix that has perforated and you can just see all of the edema that we see in just this big fluid collection, a big flagman down there.

So make sure that you don't call this normal appendix because you see what looks like it, but this is typically what a perforated appendix will look like and you can see that there's increased blood flow within that meso appendix.

Another false negative is looking at gas filled appendix. So you can have gas from inflammation, you get acoustic shadowing and often it may be limited to a certain portion.

So I asked told you that we'll talk about how to tell the difference of normal air in the appendix versus gas in the appendix from inflammation. This is a case that we can see in long axis view. Here you can see that there's a completely gas filled short axis view. We see the same thing.

The way you tell the difference is if you have normal air within the appendix, you will not see the thyroid in the belly. But this is a case of that we have appendicitis. You can see all the edema surrounding it.

So this is air within the appendix from inflammation and not just normal air within the appendix.

If you mistake a markedly enlarged appendix, I've never seen an appendix measuring over two centimeters in size and I think the reason is they will perforate before they reach that size.

So if somebody mistakes small bowel or identification of the distal tip, this is the case, that we measured that this to be two centimeters. And actually what happened when this patient went to surgery, this appendix had actually perforated and this is just sort of inflammation surrounding it.

Now looking at this, this looks like it's an abnormal appendix approximately two centimeters in size. But if you were watching this real time, this is just a loop of small bowel that was peristalsing that we happened to freeze right when it looked like that.

So the key to making that diagnosis and being able to scan this in real time and know that you're not looking at a case of appendicitis. Also there's no thyroid in the belly where you see the inflammation on this particular image here.

False Positives

Now what are some pitfalls that can lead to a diagnosis of a false positive resolving appendicitis. If you have a dilated fallopian tube and you mistake that for being the appendix, if you accidentally mistake the SOAs muscle and you're like how on earth can you do that? But I've actually seen where this was done before.

If you look at per appendicitis from other surrounding inflammatory processes and we'll talk about that or if somebody mistakes a stool and assumes that it's an append with when you're scanning over the cecum.

So looking at resolving appendicitis, it's fairly uncommon, but it can resolve spontaneously. And the key to that is typically these patients will not have an append if when they do have the resolving appendicitis.

So this was a, of course it was one of the daughters of one of our radiologists who happened to be home on spring break from looking from her college and she came in with right lower quadrant pain. We scanned, she had hyperemia, but you can see her appendix is normal in size.

So we did follow her up again and next time we took a look at it, it was still normal in size but no increased blood flow within that. So we assume that she did have a case of resolving appendicitis.

Now the way that we tell the difference between a dilated fallopian tube and the normal appendix especially you're scanning on individual sonography, is looking for the undulating mucosal folds. Those you will see within the fallopian two, you do not have the echogenic submucosal ring.

And as already mentioned, this is something that we will see on endo vaginal sonography. So looking at this case, it comes down to a blunted in it possibly could be appendix or also a lot of patients that do have PID going on, they're gonna know that they have a pelvic inflammatory disease a lot of times or they can test to see if it is pelvic inflammatory disease clinically.

But when you scan this fallopian tube in a short axis view, you'll see these little mucosal folds that come in. This is the distended tube and you can see the fluid.

Now this also is an inflammatory process, so you will see the thyroid in the belly when you have a patient with an abscess tube. So very similar to the appendix, but the key to this diagnosis is looking for those mucosal folds that we'll see with the fallopian tube.

If somebody accidentally mistakes muscle fibers of the SOAs, the key is to make sure you scan sagal and what will happen is the fibro fatty tissue between the muscle fibers will fake you out transverse orientation that you'll look at within these muscle.

So this was something that I created but one of our sonographers actually on call had scanned looking in this type of view and measured from here to here and called this an abnormal appendix. And all she was doing is scanning a very thin patient looking at the SOAs muscle.

And when you rotate the transducer 90 degrees, you possibly could measure something through here and say that this would be a normal appendix. But once you rotate 90 degrees and the key to scanning anything with ultrasound is to always visualize it in two planes.

When you rotate 90 degrees you aren't going to pick up the same type of thing. And, and if you scan up and down and across, eventually hopefully you'll realize that you are scanning the SOAs muscle and just looking at normal muscle fibers.

Also when we look for false positives is from other surrounding inflammatory process, what happens is you get extrinsic inflammation that could cause serosal edema. Also it'll cause thickening of the appendix.

There's something that we've all heard of Crohn's appendicitis. Typically patients that know they have Crohn's disease, this is something that will start in the terminal ileum. So most patients that have Crohn's disease know or they're aware that they have it, but you can get what's called Crohn's appendicitis that will cause the appendix to be inflamed.

Also, when they do have active Crohn's and as already mentioned, a tubal ovarian abscess can cause inflammation surrounding structures and actually cause you to have a false positive diagnosis on the appendix. But typically once that is treated, the inflammation from the appendix will resolve on those.

So looking at surrounding inflammation, here you can see this is a patient that had active Crohn's disease. You can see all the inflammation within that. As already mentioned, most of these patients know that they have got Crohn's disease.

This is another example of Crohn's disease is a scanning over the terminal. Ileum Crohn's disease is a transmural process so it actually affects all layers. With inflammation you can see that thyroid in the belly type of appearance surrounding this patient in scanning the terminal ileum.

Crohn's disease typically would be something that more would be diagnosed using ct.

This is a patient that came in with right lower quadrant pain. They started out with an ultrasound where you can see that this is the small bowel that we can see is inflamed and then we saw what looked like an area that had been perforated.

You can also see just all the edema surrounding that, but of course they're not going to trust an ultrasound diagnosis. So this patient went ahead and had a CAT scan and it was confirmed that not only was their Crohn's disease but they had perforated through this.

So this is a surgical emergency anytime you've got small bowel with perforation there. But a patient that definitely had active Crohn's disease with a perforation.

Another thing that we can see sonographic is diverticulitis. Now diverticulitis, the most common location for that is the left lower quadrant, right where you have your descending colon and your sigmoid colon joint up. So sort of at the descending sigmoid junction is the most common location.

This was a case of in vaginal sonography when we scanning out towards the left ovary, just notice some thyroid in the belly surrounding the ovary angled up from that and found this case of diverticulitis.

So here's the inflamed diverticulum. Once again, it's an inflammatory process. You can see that thyroid in the belly or the edema of the fat.

This is another example of diverticulitis is a scanning with a transabdominal high frequency linear rate probe. You can see the diverticula shadowing behind that. Also edema of the fat.

And looking at this, you can see what looks like normal colon and here's the inflamed diverticulum and a couple adjacent ones and also edema of fat that we can see within there.

So these are all some examples of diverticulitis case of PID and you can see this very fairly large distended tube. We have got some layering of the fluid. Part of this is inflammation also part of it is just the through transmission that we can see within that.

But this is a patient that came in with right lower quadrant pain and it was due to pelvic inflammatory disease and not appendicitis. Also, since it's an inflammatory process, you can see that there's hyperemia within the adnexal area.

So any type of inflammatory process you're going to have that increase in blood flow and edema, the fat surrounding it.

Inspissated Stool Mimicking Appendicolith

So the last thing would be inspissated stool where you mistake normal stool in the colon for an append lift. What you'll see is an acoustic shadow. Typically it's going to be within the ascending colon and not the appendix itself.

You know, if there's any question of that, an abdominal x-ray can be done. But we've actually seen cases of where somebody mistook inspissated stool and thought that it was an append within that.

Conclusion

But now that we have had enough about appendicitis, that is all we're going to cover. And I wanted to thank you all for listening to this lecture.