0:02

Hello and welcome to Noon Conference hosted by M R I Online Noon Conference

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connects the global radiology community through free live educational webinars

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that are accessible for all and is an opportunity to learn alongside top

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radiologists from around the world.

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We encourage you to ask questions and share ideas to help the community learn

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and grow.

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You can also sign up for a free trial of our premium membership to get access to

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hundreds of case-based micro-learning courses across all key radiology

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subspecialties. Today we are honored to welcome Dr.

0:41

Jonathan Samit for an interactive case review entitled Pediatric M S K Cases

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Jeopardy Style. Dr.

0:48

Jonathan Samit is an associate professor of radiology and orthopedic surgery at

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Northwestern University Feinberg School of Medicine,

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primarily based at an at Ann and Robert h Lurie Children's Hospital of

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Chicago,

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serving as the division Head of Body Imaging and section head of M S K Imaging.

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He also works in the adult M SS K radiology section at Northwestern Memorial

1:10

Hospital. He trained in diagnostic radiology at Northwestern University,

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followed by sub-specialization in M S K Radiology at Johns Hopkins Hospital.

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He studies nerve imaging with M R i,

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urography and ultrasound Rapid M S K imaging and M r I techniques for

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bone marrow evaluation. At the end of the case review, please join Dr.

1:32

Salmon in a live q and a session where he will address questions you may have on

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today's topic.

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Please remember to use the q and a feature to submit your questions so we can

1:42

get to as many as we can before our time is up. With that,

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we are ready to begin today's lecture. Dr. Samit, please take it from here.

1:50

Thank you very much.

1:51

My name is Jonathan Sam from Chicago Laurie Children's Hospital

1:57

and we are going to have a fun, um, case review here,

2:01

jeopardy style. And so, um,

2:05

if everyone can get their chat open, um,

2:10

we will begin. And so today

2:15

we are going to play some jeopardy.

2:46

Here's the board. Okay,

2:51

So

2:53

what we are going to do is try to make it as interactive as possible here.

2:58

And so, um, I'm going to ask the participants to, um,

3:02

use the chat function. So first, uh,

3:05

we'll ask you to just chat in which, um,

3:08

dollar amount you would like to pick.

3:10

We're gonna try to get through all the cases and then once the case shows up,

3:13

we'll ask you to try to pick the answer that you think it is and then I will go

3:17

over the discussion at the end.

3:20

We can go back to certain cases and discuss more in detail.

3:24

So with that, uh,

3:26

would everyone please look at the board and pick their first, uh,

3:30

dollar amount in case that they would want to go over. Now

3:40

I'm just looking here. Ah,

3:43

$500 for bone lesions right at the beginning. Okay,

3:48

let's go with this super hard case. So

3:55

this is a interesting thinking case. Um,

3:59

let me just show here that we have a T one without fat suppression,

4:04

a T one with fat suppression. Down below we have a PET ct,

4:08

so we have the CT portion and we have the PET portion.

4:13

So digest that here and then we will go over the answer.

4:21

So this is a hard one because have to figure out where the actual abnormality

4:24

is. So I'm looking in the chat, just, uh,

4:27

shout out what what you think is going on here and then we will review

4:42

sternal lesion. Excellent. So

4:46

when you look at the T one, um,

4:49

the sternum kind of looks normal-ish. You know, we have a fatty marrow,

4:53

seemingly fatty marrow, but then when you go to the fat suppression,

4:57

that does not suppress out and so we know it is not fat.

5:01

So it's intrinsically bright on T one, but it's not fat.

5:04

Then we go to the PET CT and we see that that area is metabolically active.

5:09

So it's an intrinsically bright T one lesion that also is

5:13

metabolically active. So now what do you guys think it is?

5:17

So you have to think about what things are bright on T one intrinsically.

5:22

So you get this answer.

5:28

So hemorrhage is bright on T one,

5:29

but that wouldn't typically be bright on the pet melanoma mets. Excellent.

5:34

So this is a case of melanoma metastasis and what that is,

5:39

of course it's gonna be, uh, T one intrinsically bright.

5:42

So this question really gets at kind of if you can figure out what things are

5:46

right on T one. And so I like this question just for the kind of, uh,

5:51

teaching about M S K, uh, m R I. All right, next one.

6:02

I saw some of before said trauma for uh, 100. Let's do that.

6:07

So this patient, um,

6:11

had a football injury, um, a valgus injury, um,

6:16

to the knee were hit on the lateral side. So what are we seeing here?

6:21

Excellent, I saw right M C L grade three.

6:25

So we can see here ligaments and tendons really shouldn't have a wavy

6:29

appearance. Um, we have a kind of black squiggly line,

6:34

so if I ever see a black squiggly line, I know something is torn.

6:36

We see the M C L should go from the femur to the tibia and it is wavy and

6:40

retracted. This was a, uh, lead M C L tear. Excellent.

6:45

Next case.

6:51

Okay, pick a category

7:02

sports 200. Okay,

7:06

this is again a pediatric case. A patient who twisted their ankle came to the ed

7:13

and in peds there's basically two main fracture types that we need to know.

7:18

Someone already got the answer. Excellent. And so, um,

7:22

what we're seeing here is a fracture line in the metaphysis

7:27

widening of the FSIS and a fracture going through the epiphysis.

7:32

So it is a tri plaine fracture. Excellent. Um, now

7:39

what we need to do is discuss what a tri plaine fracture is.

7:42

So what Salter Harris is this,

7:44

it's not a Salter Harris three because it involves the metaphysis and the

7:48

epiphysis. So it's actually a Salter Harris four. Excellent.

7:52

So Salter hers two is just a metaphysis into the growth plate salter.

7:55

Hers three is growth plate and epiphysis. This has both.

8:00

And so this is a tri plaine fracture has three planes,

8:03

one through the metaphysis, one through the ssis, and one through the epiphysis.

8:07

So the lateral view is very important to help us see that extra

8:12

component. We'll see the other ankle fracture in a different uh,

8:16

case that is the kind of cousin of this sort of two P's ankle fractures.

8:20

You need to know this is tri plan fracture. Excellent.

8:25

Alright, next one. We are going to go to someone said, um,

8:31

soft tissue for 100. Sit here. Aha. Perfect.

8:36

So this is the cousin of, um, of that.

8:41

And so, um, this is actually a trauma case. I think my categories, uh,

8:45

might have blended a bit. So this case here,

8:49

this is the cousin of the tripe. What is this here?

9:02

So in this case we're seeing

9:07

it's a trauma case. So this is sort of,

9:10

let's just say this is normal fial closure. So this part,

9:14

the lateral part closes last.

9:16

So let's say there's a little bit of widening here of the fsis.

9:19

There's actually this oblique fracture line in the epiphysis

9:24

oblique fracture line in the epiphysis.

9:28

So this is so not a pylon,

9:32

this is actually a salt of Harris three. Remember,

9:34

because it involves the excellent I see someone. Got it.

9:38

So this is a fracture through the epiphysis.

9:41

So it's the growth plate and epiphysis.

9:43

So below the growth plate is Salta Harris three.

9:46

And this is a juvenile to low fracture. What this is,

9:49

the best way I think of it is that it's an evulsion fracture of the

9:53

anterolateral corner of the epiphysis.

9:55

Remember you have your syndesmotic ligament,

9:57

your anterior tib fib ligament is gonna basically pull off the corner of the

10:02

epiphysis. So very different from a a tri plaine fracture.

10:05

So this is not going to have the metaphyseal fracture component,

10:11

but notice how these can kind of look similar on the frontal view. You have,

10:14

both of them have an epiphyseal component,

10:16

but this one is really just an avulsion fracture of the epiphysis.

10:21

So it's assault of Harris three juvenile to low fracture.

10:28

We can go over that at the end if there is confusion on that next category

10:43

from 400. Uh,

10:47

so this is a patient who is a baseball, uh,

10:51

baseball pitcher and um,

10:54

has basically this pain in the back of the shoulder has had it for some time

10:58

now. Um, we get these, uh, films here on the x-ray.

11:03

We see some density back here. Excellent Bennett lesion, right?

11:07

So we have this calcification kind of along the capsule, along the glenoid.

11:12

So this is just a sign of kind of, um,

11:15

prior injury to the labral capsular junction. Um,

11:21

bony bank heart, um, typically would be, uh,

11:25

anterior rim fracture. You can have posterior uh, as well,

11:29

but this is more kind of calcification, um,

11:32

kind of along the capsule and stripping of the periosteum. Um, and so this is,

11:37

this is, uh, a sign that there's been prior injury to the labrum and capsule.

11:45

Next, uh, we will do, um,

11:52

someone said trauma for 400, although we already did that. Let's see here.

11:56

Bone lesion 100. Okay, okay,

12:00

this is a, um, actually a very,

12:03

very fun case where you can actually come to the histologic diagnosis

12:08

just on imaging. That's why I love this case. So you have, um, a stir image,

12:14

a T one image and a CT image.

12:19

And so, um, first question is where is the lesion, right? Um,

12:23

I see a bunch of, uh, different, uh, answers here. One of them is correct,

12:27

but let's go through this. So remember this is a pediatric patient.

12:32

So giant cell, uh, tumor of bone, um, is, is not gonna be, uh,

12:37

common. And so, right, so there's a lesion in the greater tri cantor.

12:40

You can see that there's an asymmetry between the fatty marrow on the right and

12:44

the lesion here. Then when you look at the ct,

12:47

we actually see little punctate calcifications within the lesion

12:52

suggesting a chondro lesion as people said there.

12:55

When you think of the greater stroke cancer, remember that it's an hypothesis.

12:58

So you want to use your differential diagnosis for, um, the epiphysis,

13:03

right? 'cause that will be a similar differential.

13:05

And for pediatric epie lesions, chondroblast, stoma, chondroblast,

13:09

stoma and chondroblast.

13:11

And those lesions are one of the four lesions I think of that have ton of marrow

13:15

edema around them. So the lesion here produces massive edema,

13:21

acids, stoma, um, usually just a little punctate lesion. Uh,

13:24

so that's not there, eg. Wouldn't have those chondro calcifications and, um,

13:30

osteoblast, um, is not a bad thought. Um, that, uh,

13:35

is a much more rare lesion as well.

13:37

And these little conroy calcifications suggest chondroblast.

13:46

Okay, very good.

13:52

Next case here,

13:58

sports for 400.

14:10

So we're seeing something here. It's a fibular fracture. Excellent, yes,

14:14

argue with sign. Very good. So fibular fracture, but we need to know that this,

14:19

this signifies something. So what does this signify?

14:22

What do we have to be concerned about?

14:24

This is not just a regular mid shaft fibular fracture. Um, so,

14:29

so segun fracture is, is actually of off of the tibia.

14:33

So segun fracture is not correct. Um,

14:36

so l c l injury more broad category I'm looking for is what kind of family of

14:41

injuries on this side is something we need to alert the clinician, um,

14:45

that this is so LCL l injury is correct,

14:48

but it's kind of more broad poster lateral corner. Excellent, excellent. So

14:54

this should tell you, um,

14:55

that there's a poster lateral corner injury and that's important because that's

14:59

your lateral stability.

15:00

So what might kind of just at first glance look like just a little noplace

15:04

fracture. We have to remember that this, this is a very important for your,

15:06

your lateral corner, uh, stability.

15:09

And so that as opposed to the lateral bone injury. Excellent.

15:12

The L C L and biospheres attached to that location. Next case,

15:23

bone marrow 100. So pediatric bone marrow is one of the most challenging,

15:28

uh, areas I think especially if you don't do p that often. Uh,

15:32

it's one of my areas of interest. Um, and so this,

15:37

this just signifies how difficult it can be. So

15:41

this is a five month old and here is your T one. So, um,

15:45

is this normal or abnormal?

15:56

I seen normal. Excellent,

16:01

excellent. I saw someone put leukemia. Now this is very tricky,

16:06

right? So, um, general rule is that, um,

16:12

skeletal muscle and bone marrow.

16:14

So bone marrow should be brighter than skeletal muscle if darker than skeletal

16:17

muscle.

16:17

You're concerned it gets harder and harder as you deal with younger and younger

16:22

patients. So when you're born, you're basically full of cells,

16:24

you're all red marrow. As we age,

16:27

the marrow will convert in a predictable pattern to fatty marrow.

16:31

And so in the adult world,

16:33

we might only see a little bit of marrow left in the metaphysis. In pediatrics,

16:38

the first thing is you're gonna see the epiphysis turn fatty,

16:41

then you're gonna see the diaphysis turn fatty, and then over time, over years,

16:46

you'll start seeing more and more fatty marrow come in.

16:50

So we will talk more about this, but that is red marrow. Next case

17:00

sports for 500.

17:16

So looking for a so good.

17:19

So it is a meniscal tear looking for a exactly looking for

17:24

the kind of tear. We're seeing this beautiful parrott beak, um, tear.

17:29

So it's a kind of radial tear. And I like this case a lot because I,

17:32

I use the axials just to see if I get lucky. Sometimes on the ales,

17:37

if you cut just right through it, you might see the tear, um, to a really nice,

17:42

uh, uh, vantage point. And so you see a parapet tear is a radial tear,

17:45

but it kind of curves.

17:46

So that components of a longitudinal and a radial tear on a coronal when you're

17:51

going through a radial tear,

17:51

you'll see the vertical line will move to different locations as you're

17:55

scrolling through it. I also like the axials for root tears.

17:58

So you might see a ghost sign on a sagittal, but then when you go on the axial,

18:02

you'll see an actual cleft and you can see the actual, um,

18:06

tear gap for root tears as well. Exactly. Very good.

18:16

Next case. You guys are doing great.

18:19

These are too easy for you p p e 100. Okay,

18:26

this is a patient who presented with fever and ankle swelling

18:32

and we have this x-ray coming in through the ed. Aha,

18:37

very good.

18:38

So we see a rounded bone lesion in the metas near the growth plate.

18:43

We have periosteal reaction and we have swelling.

18:45

So you guys know that osteomyelitis is,

18:49

is very common in the metastasis because there's a blood bo uh,

18:52

it is typically a bloodborne infection

18:56

in pediatrics and we'll go to areas of high blood flow. So the metaphysis,

19:01

um, is a spot where you often get osteomyelitis.

19:04

So if you see what it looks like, a bone lesion, a loosened area,

19:08

think about complications of osteo. This is a Brody's abscess. Excellent.

19:13

And this, uh, will need a surgical intervention.

19:24

See we want to do, uh, for soft tissue for 100. Okay?

19:30

Um,

19:30

this is a patient with a mass and these are both T two weighted images.

19:44

Good, good, good, good, good, good. So what we're gonna do is,

19:48

you guys are all correct, but we are going to um,

19:51

we are going to help with the terminology. This is a very confusing area.

19:56

The terminology in the literature has a lot of kind of confusing things.

20:01

Um, I encourage you to go to the, um,

20:06

is a, um, classification, uh, which is International Society of Vascular, um,

20:11

anomalies. And they have kind of developed a very nice, um,

20:15

website and classification to help us communicate to our vascular

20:20

anomalies specialists so that we're all speaking on the same page.

20:24

What this is is a vascular malformation,

20:28

but within that broad category, it is a venous malformation.

20:32

It has a lilith,

20:34

it is a T two bright lesion with lobulated margins and this is

20:39

a venous malformation. Now hemangioma, um,

20:43

is sort of an older term. We wanna shy away from that.

20:46

So we only wanna wanna say hemangioma when we're talking about avascular tumor.

20:50

So that is a case where we have a solid hypervascular lesion.

20:55

It may be present at or around birth. Um,

20:58

it will often have an a growth arc where it will grow rapidly and will

21:03

involute over time.

21:06

And so reserve the term hemangioma for when you're really talking about a solid

21:11

lesion in the vascular malformation category,

21:14

you're gonna have high flow and low flow malformations,

21:18

venous malformations very common and that is going to be a slow flow.

21:23

Also avoid the term venal lymphatic, um,

21:27

try to separate venous malformation from lymphatic malformation.

21:31

Typically it's one or the other.

21:33

There are some times where you can have both components,

21:36

but usually it's not both venous and lymphatic.

21:40

So try not to say venal lymphatic unless you truly think there are components of

21:45

both. So that's how to think about these vascular lesions. Um,

21:50

so again, this is not a hemangioma, this is a venous malformation.

21:54

This is a Levo Ethereum and we can go over that more if that was a bit

21:57

confusing. Next,

22:08

we already did that one, so we'll go on to the next one. Uh, soft tissue 200.

22:15

This should be straightforward for you guys.

22:16

This is a T two and a post contrast of the knee.

22:21

And we have a T two bright structure going between the medial head of the

22:24

gastroc and the semi menos tendon.

22:28

It has rim enhancement and this is yes, a baker. Now, um,

22:33

I also show this case to, um,

22:36

remind people that we don't need an M R I to diagnosis.

22:41

We can use ultrasound. Um, this patient, um,

22:45

might have had to get full on, uh, general anesthesia.

22:50

So it's something that's just too aggressive to do for a child. Um,

22:55

if we just put an ultrasound probe, we can diagnose it. Um,

22:59

why did we use contrast? Um, sometimes these tests get ordered.

23:03

The patient might have felt a mass,

23:05

the clinician might have not known this was a baker cyst.

23:07

It's much less common impede in a small child to have a baker's cyst.

23:12

So if they felt a mass,

23:13

they might have not known and it can get ordered with contrast.

23:16

But I encourage you to try to, uh,

23:21

do ultrasound if you can have a superficial mass because then you don't have to

23:24

do an M mri. Um, someone said, uh, bursitis.

23:29

Um, so thi this is more of just a baker cyst. It's,

23:32

it's not at the level of the, of the pesan and bursa.

23:36

And one thing also is, um,

23:39

the reason we harp on that it goes in between the semimembranosus and the immuno

23:42

head of the gastroc is because occasionally you will get like a synovial

23:46

sarcoma, which can look t too bright. Um, and that, um,

23:51

if you're going very quickly,

23:52

you might see something that's not exactly in the location of baker cyst and you

23:56

just wanna be careful not to just very quickly call someone a baker cyst or a

24:00

ganglion cyst, um, to make sure that it truly meets criteria for that

24:06

next case.

24:11

Bone lesions 200.

24:15

This is a three-year-old.

24:28

Okay, so we have a few different answers now.

24:38

Okay, good. So this is a hard case. Um,

24:43

we know that we can use location to help us

24:48

with a differential diagnosis and everyone knows that when you see a dile

24:53

lesion, you should be concerned about you sarcoma. However,

24:56

we have a lot of features here that don't really fit with you in sarcoma.

25:00

First of all, if you go back just to x-ray,

25:03

we don't really have a permitted lesion. We have a geographic loosen lesion.

25:08

We have really kind of solid non-aggressive periosteal

25:13

reaction around the lesion.

25:14

So a ung sarcoma would not have a very kind of benign reaction,

25:18

also wouldn't look like a punched out like lesion on m r i.

25:23

We have massive bone marrow edema around this lesion.

25:25

The lesion is extremely reactive. Typically, uh,

25:30

bone cancers don't have quite this much edema. Also,

25:34

three-year-old is very young for you in sarcoma,

25:36

something you think about and I see someone has the answer. And so, um,

25:41

this is actually longer hand cell histiocytosis,

25:45

previously known as eg eosinophilic granuloma.

25:48

It is a kind of inflammatory type bone lesion. It is a neoplasm,

25:53

but it can have a benign course.

25:55

And so it often can present as a solitary bone lesion and can be very confusing,

26:00

um, when you see these cases. But just remember that, um,

26:04

they are called a great mimicker, um, traditionally as in our teaching,

26:08

but in fact on m r I, they have a very predictable appearance.

26:11

They're lesions that are typically, um, very, very reactive.

26:15

They have a bunch of paralegal edema, yes, this probably would go to biopsy.

26:21

Um, and sometimes when they do the biopsy on the touch prep,

26:25

if they see a lot of eosinophils,

26:27

they'll call the clinician and they will ask if they, uh, if they want, um,

26:32

to inject intralesional steroids, which is the treatment for this,

26:35

if they see round blue cells and they won't.

26:37

But often what we do is we biopsy it, we do a touch prep. If, um,

26:41

there's no round blue cells, then we can give intralesional steroid.

26:46

And um, this was L C h, so cool case.

26:50

Just keep that in the back of your back pocket for, um, young lesions.

26:56

All right, uh, someone said soft tissue lesions 400.

27:04

So, um,

27:07

let's say this patient, uh, has had a, um,

27:13

history of colectomy for some, uh, polyposis, uh,

27:18

um, issue. Ha I gave it away.

27:23

And so this is a I fibromatosis case, a desmoid case, very, very good.

27:28

Um, when I look at a lesion,

27:30

if I see very black areas on T two,

27:34

there's not really much else that I think that's,

27:37

I think that's very suggestive of a desmoid.

27:41

It is the fibrous material.

27:42

The more grayish or T two bright areas of the tumor are thought to be the more

27:47

cellular, uh, areas as we follow these lesions over time, yes,

27:52

Gardner's is the answer. As we follow these lesions over time,

27:55

you will see them get blacker and blacker and smaller on imaging.

27:59

And that to me is the kind of,

28:01

I think of it as like the collagen versus the fibroblasts.

28:05

So it's becoming less and less cellular. It's becoming blacker more,

28:09

more just fibrous and they will slowly, uh, um, change over time.

28:15

And, uh, conversely, if it is recurring,

28:17

often we'll see new areas of enhancement, new areas of T two bright signal.

28:21

And so that's one area,

28:22

that's one way that I can try to assess if the lesion is responding to the

28:27

treatment.

28:35

Soft tissue lesion 300.

28:39

So this is an eight year old girl with an elbow mass.

28:43

Here's a T two and here's a post contrast.

29:02

Okay? So first I'm gonna describe the case.

29:07

Think about that other venous malformation case and how this looks different.

29:11

So what we have here is a T two kind of intermediate

29:15

hyperintense lesion, right? It's not fluid signal, it's large

29:21

smooth margin. On the post contrast, we have kind of heterogeneous,

29:26

but solid enhancement, right? This is not over the lec,

29:30

so not renon bursitis. Um,

29:33

synovial sarcoma is not a bad thought. Um,

29:37

this should tell you that you're, you're dealing with a solid,

29:41

solid enhancing lesion.

29:42

So lymphatic malformation is not correct because lymphatic malformation on post

29:46

contrast would typically be, um, only rim and septal enhancement.

29:51

It's a cystic lesion. This is a solid lesion.

29:54

So you need to think about your differential perb malignant solid lesions. Um,

29:59

let's say this is intramuscular. And so, um, hemangioma is,

30:03

is is not a bad thought,

30:05

but an eight year old usually wouldn't present with hemangioma at this age.

30:08

So we have to be concerned on this case, um,

30:11

when we think of soft tissue malignancies and pediatrics. Yes.

30:16

So rhabdomyosarcoma is the one we need to rule out. Um, that is,

30:20

that is,

30:21

that is our kind of most common soft tissue malignancy rhabdomyosarcoma.

30:26

And so that is what this was. Um, unfortunately

30:34

someone said bone lesion for 400, let's go there.

30:38

So this is a nine month old little baby,

30:43

and what we have is a T one and a stir.

30:46

And so work through this here.

31:04

So I will tell you that, uh, yeah,

31:06

extramedullary hematopoiesis is not as common.

31:10

We don't usually get the masses and that's not a,

31:12

not a bad thought in a young patient. What are we worried about?

31:16

Are we worried about? So first of all, the T one is very, is very, very dark.

31:20

And the, the t the stir is too bright, so the marrow is diffusely infiltrated.

31:25

So leukemia is, is a good thought, but we also have this other stuff here.

31:30

And I didn't show you an axial. Yes, someone got it.

31:33

We have soft tissue masses kind of extending into the canal.

31:36

So leukemia lymphoma's, not a bad thought,

31:38

but nine month olds kind of young for that.

31:41

When I see someone under one years old with this, I think of neuroblastoma.

31:46

Neuroblastoma.

31:47

So neuroblastoma can have soft tissue masses that go into the canal and

31:52

can also have diffuse marrow replacement as well.

31:57

And so this was metastatic

32:08

trauma 500.

32:13

So I only have this one slice, so it's kind of artificial. It's hard to,

32:16

to kind of, uh, show these kinds of cases,

32:19

but I'm right at the level of the notch,

32:23

so there's something that shouldn't be there. Excellent.

32:27

So this is a displaced bucket handle type tear with flipped meniscal tissue into

32:32

the notch. Very, very good. I,

32:49

so this is a patient who is, um, a young patient, plays sports a lot,

32:52

didn't have an acute trauma, but has this pain for the past few months.

32:57

And here is the M r i.

33:03

Excellent.

33:04

So what we're seeing here is an osteo conran diskin lesion in the media femoral

33:08

conduct. Now let me ask you, do you think this is stable or not?

33:13

What are features that we can use to try to predict stability?

33:21

It is stable?

33:23

What are some features that would make you concerned about this being um, uh,

33:28

uh, unstable? Right, so in this case,

33:32

we see a little subconscious sclerosis and a little bit of a edema.

33:35

We don't have a well-formed fluid cleft.

33:38

So I look for kind of that Oreo cookie sign, um,

33:41

where you have a white line bounded by black lines. We don't have any cysts,

33:46

so cysts are bad as well. We don't have a cartilage defect or a fluid cle, um,

33:51

or fissure overline lesion. The subc choral bone plate is intact.

33:55

So I do like an outside in approach. I look for the subc chondral,

33:58

I look for the, uh, cartilage. I look for the, um,

34:01

subc chondral bone plate disruption. I look for that well-formed fluid cleft.

34:04

And I look for cysts. Now I will, um, no, I would not do an arthrogram. Um,

34:10

we rarely do knee arthrograms, I don't think in necessarily

34:14

tells you. I think the issue with O C D is when you're in the adult world,

34:19

and I read for adult as well,

34:21

if you see those features that we just talked about of fluid cleft formation,

34:25

it correlates more closely with instability at arthroscopy.

34:29

The problem in pediatrics is that you don't have that same assurance.

34:34

So you can have some of those features and when they go to surgery,

34:37

it actually is stable. When the M r I looked kind of unstable.

34:41

So the problem is, um, this is one of my areas of interest as well,

34:43

is that we don't have the best way to totally predict in peds we can kind of

34:47

guess, but in general, peds you kind of need more, uh,

34:51

more of those bad findings to, to correlate with, with instability. Um,

34:57

the problem with arthrogram, first of all, it's invasive. In pediatrics,

35:00

we try not to do, uh, as much. Um, if you, if you see car,

35:05

if you see flu undercut it, does that necessarily mean it's gonna be unstable?

35:09

The problem is it's not, it's not such a great, um,

35:13

it's hard to be definitive anyways. Um, I find so, uh, it's, it's,

35:18

it's just an area that if it's not necessarily gonna help you,

35:20

then why do an invasive test? Um, uh, some centers, uh,

35:24

don't do any arthrograms, uh, at all.

35:26

I think people are moving away from agram now that we have three Tesla scanners.

35:29

Just in general, just my kind of 2 cents there.

35:32

I think it's if you have someone who's, um,

35:35

where there's a very strong clinical question and you have an orthopedic surgeon

35:39

that you work with closely and they're gonna go to surgery and they want their

35:42

totally reasonable. But, um, I think a lot of things can be answered without it.

35:47

So that is, uh, probably a little too much there. But, uh,

35:50

just some basic things on O C D for us.

35:55

Trauma 300. So, uh, again,

36:00

this is a patient who is actually three years old and mom noticed

36:05

a kind of funny thing when the kid is walking around, they, uh,

36:09

have a clunking and they have a clicking. Excellent.

36:12

So we see that the meniscus is way too big, super enlarged. Um,

36:17

so the question we have is what to do with these, right?

36:21

So we have an enlarged display meniscus. First of all,

36:25

in pediatrics we don't have the greatest definition adults,

36:27

we typically will look for that three slice rule, right?

36:31

Which basically tells you that if you have five millimeter slices and you go

36:35

three slices in on a sagittal, that would be about 15 millimeters. So I,

36:39

in the adult world,

36:39

we kind of use like 14 millimeters or so in the transverse dimension to diagnose

36:44

discoid. In pediatrics, of course,

36:46

you have kids with multiple different ages and sizes. Um,

36:49

so it's difficult to just give one number. Um,

36:53

people will kind of look at it.

36:54

If it goes kind of past the midpoint of the condyle then might start suggesting

36:58

it. But really more so, uh, than just diagnosing. Do you have discoid,

37:02

yes or no? Uh, the question also becomes really in a practical level,

37:06

if you are faced with a discoid meniscus, uh,

37:09

the orthopedic surgeon has a dilemma because you have a patient who is basically

37:14

kind of healthy and doesn't have a problem.

37:16

Now yet we know that DySIS sky are more, um,

37:21

more at risk for tearing. In fact, if you have a really big meniscus, uh,

37:25

then you most certainly going to tear. Um, and so,

37:30

um,

37:31

our group put out a paper just trying to come up with some factors that might

37:37

make someone more at risk for, uh, meniscal failure.

37:40

So if you have an intact discoid, we found that if the meniscus was, um,

37:44

very large relative to the, the tibial plateau,

37:47

so more than 50% of the compartment,

37:50

that that was a risk factor if you have the intra substance signal that you

37:54

detect. That was also a finding if the patient has mechanical symptoms. And so,

37:59

um, tho those, those findings of the larger it is, the more signal it has in it,

38:04

maybe they would, uh,

38:06

be a bit more concerned about that patient because it's hard to kind of convince

38:10

a parent to, you know,

38:11

have a a three-year-old undergo surgery if you don't have a tear at this time.

38:14

So these are just things to think about when you're faced with a disco meniscus.

38:22

All right, next case,

38:28

400 sports, 300. Uh, okay,

38:33

sports 300. Just an easy one here.

38:38

Um, we have a image at the notch.

38:51

Yes, this is just an a c l tear, even an empty notch.

38:54

Here you see the A C l I like to look at the coronal and the sagittal.

38:58

The sagittal can be kind of tricky sometimes, um, can be, uh, can fool you.

39:03

Uh, so always look at the, um,

39:07

the sag of the coronal as well. Very good.

39:14

Alright, and then, uh, going back here, someone said, uh, I think someone said,

39:18

um, oh here, bone lesions 300. Okay, so

39:24

this is a five with hip pain. Um, now, um,

39:32

does anyone see anything here? They just have bone pain. They have hip pain.

39:37

Anything wrong with this here?

39:47

So this is, um,

39:53

basically a diffuse marrow replacement. Uh, and so, um,

39:58

the sacrum might have been heterogeneous because of differential end

40:01

replacement. This is sometimes you have, um, soft tissue,

40:04

it kind of oozes outta the bone. So again,

40:07

what we're gonna do is look at the marrow relative to the, uh,

40:13

tain muscle. Okay? The, uh, sorry, the, the muscle, uh, skeletal muscle.

40:16

So it's darker than skeletal muscle and it's super bright.

40:19

Diffusely on stern staging usually should have kind of grayish signal.

40:24

And one kind of tip that I use, um, in,

40:27

in patients that are a bit older is the epiphysis really should be fatty.

40:31

If you see, um, if you don't see a fatty epiphysis, that is,

40:36

that is a finding very concerning.

40:38

For a malignant marrow replacement sickle cell, you would have definitely, um,

40:43

read marrow, but the fatty,

40:45

the fat and epiphysis would typically be preserved and it wouldn't be quite this

40:49

intense of signal on the stir. Um, so, so, um,

40:55

this, this was a patient with acute leukemia, uh, a l l, uh,

41:00

in, in a pediatric, uh, patient,

41:09

400 P per E.

41:23

So this was a patient, um, with, um,

41:29

very close, very close if I tell you that. So there is a fat, fat fluid level,

41:34

however, um, to see this black thing and circling the bone.

41:39

So this is actually not the joint, it's a subperiosteal collection.

41:44

It's a subperiosteal collection.

41:47

So there's a fat fluid level in the Subperiosteal collection. Yes.

41:52

So this happened to be osteomyelitis with a subperiosteal abscess,

41:57

and occasionally you get a fat fluid level. So really, um,

42:01

fat fluid levels tell you that the marrow is damaged and you're

42:06

gonna have, uh,

42:07

the lipo blasts and the fatty marrow will kind of burst and you will have

42:10

leaking of liquid fat into the, either the joint space,

42:15

like in trauma, we have lipo, hemo, aosis,

42:18

but you can also have it into the sub periosteum. And so I've seen, um,

42:23

I've seen fat fluid levels in, um, in infection.

42:27

I've seen it in trauma and I've also seen it in, um,

42:31

severe bone infarct.

42:32

So some of our pediatric patients who have gaucher's disease might have like a

42:36

huge medullary infarct and it can kind of leak out. And, uh,

42:40

similar concept to marrow, uh, basically becomes more liquified.

42:44

And so that, that's the reason that you, you have some of these fat full adults.

42:47

But in this case, remember that this, uh,

42:51

black layer is actually the periosteum lifted off the bone.

42:54

And so this was osteomyelitis with a subperiosteal, uh, abscess

43:03

500, but I don't see the category

43:14

really double. Normally we would, uh, be gambling here,

43:18

but let's just go over the case.

43:20

So here you have a stir image and a post contrast

43:25

image, and there's a hint for you there.

43:31

Excellent.

43:34

So what we're seeing here is something that can fool us and

43:39

we have a rounded mass like area with a ton of edema.

43:44

On the post contrast, it actually looks like solid enhancements,

43:46

so kind of scary looking, right? Um,

43:50

but because we gave you the hint, you have to remember that,

43:55

uh, just as sort of lava turns into rock, right?

44:00

As the the bone is developing in myositis sci hands, um,

44:04

the early stages can be very, very, um, kind of, uh,

44:10

inflammatory, like not inflammatory, but very kind of scary looking.

44:13

Can have a lot of enhancement, can have a lot of edema. And so, um,

44:17

what we did is we recommended a CT a few weeks later.

44:22

And you can see here that there is this zonal phenomenon of

44:27

calcification that will occur.

44:28

You can do an x-ray as well of myositis acidic hands.

44:32

And so it's something to remember whenever you see something with a ton of edema

44:36

around, it doesn't quite fit. Um, you don't wanna rush to biopsy because, um,

44:41

myositis acidic hands can have a tumor like mass, like, uh,

44:46

condition muscle tear. Um, that, that is a good thought as well. And,

44:51

and they're probably, if you're developing myelo cyto specific hands,

44:55

often it's related to some trauma and you may have had a muscle tear with a

44:59

hematoma and then it forms mo so they're probably all in the same family to be

45:02

honest. Um, if you have a tear, it could develop, uh, mo. Um,

45:06

and so, um, that's probably the same kind of family

45:16

500. So we'll do soft tissue lesions for 500.

45:20

This is a five-year-old with a mass in the thigh,

45:33

right?

45:34

So what we're seeing is an intramuscular where subfascial,

45:39

we're seeing a lipomas lesion with some septations, right?

45:43

So if we're reading for the adult side, we're concerned for, uh,

45:46

atypical lipomas tumor or lipos sarcoma.

45:49

Pediatrics almost never get lipos sarcoma.

45:52

We get LipidBlast and LipidBlast.

45:55

Oma is a benign but locally aggressive lesion.

45:58

So if I ever see something on the ped side that kind of looks like what I would

46:01

call an atypical lipoma on the adult side,

46:04

I think of LipidBlast stomach and that is what this case was.

46:10

And it's too complex for lipoma good

46:16

500 again

46:32

slim. So we're seeing an early mire flask deformity,

46:36

a little bit of infiltration of the marrow, but not marrow replacement, right?

46:40

And this was a patient who, um, had Gaucher disease.

46:44

So when we have gaucher's patients, we will typically follow them.

46:48

We'll do an abdominal MR and um, bilateral thighs, and we will look for, um,

46:54

uh, basically, uh, the sizes of the liver and the spleen.

46:58

We'll track the volumes for them and we'll look at the marrow to see how much

47:01

gauche infiltration there is.

47:14

Okay, we're almost getting to the end here. Let's see what other cases we have.

47:18

P p e for 200.

47:22

This was a patient through the ED with ankle pain and swelling,

47:36

no trauma, just, uh, pain and swelling

47:43

and a white count.

47:50

So this is, um, this abnormal bone marrow signal.

47:56

But what is this here? What is this black line?

48:00

This is something that's very specific to pediatrics.

48:03

And on the axial you see that this black thing is lifting off the cortex

48:08

and there's fluid underneath it. Subperiosteal abscess,

48:12

subperiosteal abscess. This is something we don't see in adults.

48:16

The periosteum has looser attachments to the bone than in

48:21

adults. And so what happens is the infection kind of oozes out,

48:25

but it's held in by the periosteum, um, most of the time.

48:30

And so even though this doesn't look like much,

48:32

this is a subperiosteal abscess and will need to be trained

48:40

and do, uh,

48:41

p p for 302 year old with limp

48:46

post contrast.

48:56

So, um, two years old is,

48:59

is too young for osteosarcoma, okay? Two years old is too young. Um,

49:05

what we're seeing here is actually a ri enhancing

49:09

lesion, a ri enhancing lesion in the metaphysis. And we have a ton of edema.

49:14

We have soft tissue edema, we have bone marrow edema.

49:18

So remember when you see something with a ton of edema,

49:21

think inflammatory infectious first, then look at the age.

49:25

So osteosarcoma is, is older, two years old, very young L c h,

49:30

not a bad thought. Again, this ended up just being a brody's abscess.

49:33

I know I only showed you one image, but it's a rib enhancing thing on T two,

49:37

it was fluid. And the metaphysis is an area where we,

49:41

where we often see osteomyelitis.

49:50

Okay, we can go through these here. We'll do bone marrow for 200. Uh,

49:56

this was a patient that, uh,

50:01

funny bone marrow pattern. Can anyone kind of figure out what this is here?

50:05

What is, uh, exactly. Very good. So let me ask you,

50:09

which part is the post-radiation part? Is it the cervical or the thoracic?

50:19

The cervical. When you radiate, you kill all the cells so it becomes fatty.

50:24

So the lower part is just the normal marrow. And the upper,

50:27

upper part is the cervical is the, uh, radiated marrow. Very good

50:52

hint. My bone marrow always looks like this.

51:00

Um,

51:01

well what we're seeing is kind of more than expected

51:06

dark signal and bright signal here. But remember that the epiphyses are spared,

51:11

the epiphyses still look fatty. So we're,

51:14

we're a little concerned about the bone marrow,

51:16

but we actually don't think that it's a marrow replacement.

51:20

'cause it's not really the epiphysis, it's not totally diffused,

51:24

but the patient has an underlying hematologic condition that

51:30

is causing them to have more cellular marrow than normal.

51:34

So this is sickle cell disease. Someone said anorexia. So anorexia,

51:39

um, is, is a good thought.

51:41

So there's a concept of gelatinous transformation of the marrow in severe

51:46

anorexia. And, and it typically, uh,

51:48

what it'll look like is sort of a very dark T one on all of the bones and,

51:53

and bright stir everywhere. Uh, so, um,

51:57

it's not anorexia in this case because it's really just in areas that we expect

52:01

to see red marrow. You just see more of it. So this is just, uh,

52:05

hyperactive red marrow in sickle cell.

52:11

And uh, this is actually the last one here. Um,

52:14

this is an adult patient just showing a good teaching case.

52:17

So on this side we have, um, so it's a history of breast cancer.

52:22

Uh, this is, um, the first, uh, MR and then only two months later,

52:27

uh, we got this Mr. So, um,

52:30

the patient is undergoing is is undergoing treatment for red, for, um,

52:33

breast cancer. So someone saw this and was a little bit concerned is this,

52:37

what is this? Aha, very good. So you guys, uh,

52:42

over it, this is just red marrow reconversion. So look at the timeframe.

52:46

We're not gonna say diffuse marrow replacement, even though it changed rapidly.

52:50

Uh, we know that it's probably related to the rebound, uh,

52:52

red marrow coming back. Okay, so, um,

52:58

we made it through all the cases. Um, I am free to answer questions.

53:03

I have the chat open. Uh, you guys were awesome. You, you got all the cases, uh,

53:07

it was a lot easier than, uh, than than I, than I anticipated,

53:11

but hopefully you learned something. Um, and uh, if you'd like me to go back to,

53:16

um, any particular case, we can discuss it further. There's lots to discuss.

53:20

Uh, thank you, thank you, thank you. Um,

53:23

thought it's just a fun way to kinda showcase this. Actually,

53:26

I realize there is one more question, um, here.

53:29

Forgot to click on the final jeopardy for you guys. Kind of a fun,

53:34

fun little case here. This is a coronal image of the back,

53:39

coronal image of the back. And we're basically showing you T two,

53:44

T two fat set and gadolinium. Very strange case,

53:48

but you can kind of think about it and and figure it out. Uh,

53:53

yes,

53:54

this is basically a plexiform neurofibroma plexiform neurofibroma using the

53:59

little target signs. And this patient probably had nf so just a fun case there.

54:06

So, um, yes, so thank you again and uh, let's see if we have any questions.

54:11

How to tell benign from malignant soft tissue lesion,

54:14

the elbow RedR sarcoma from other benign. Okay, so, um,

54:19

first thing I do is I wanna see, um,

54:23

if something is a solid, um, enhancing lesion. Okay?

54:29

So if you have a, um, a cystic lesion, an Ms K, it's, it's not,

54:33

not usually gonna be, uh, malignant. Um,

54:36

so first thing is to detect if you have a solid lesion.

54:38

If you have a solid lesion that is enhancing,

54:41

you kind of need to keep, uh, malignant in the differential.

54:45

There are benign lesions, but um, we have to,

54:48

we have to probably biopsy it if we see a solid lesion.

54:52

The venous malformation case, if you, if you looked at it carefully,

54:55

it had kind of more kind of lobulated kind of little finger-like projections.

54:59

Usually tumors are more ball like lesions, they're smooth. Um,

55:02

and on the post contrast would not have a solid heterogeneous enhancement.

55:05

You kind of need to look at all the different projections to, um, figure it out.

55:09

Uh, let's go to the L C H case. So L C H is a very cool entity.

55:15

Um, it is a fuller for sure. Um,

55:19

it is a lesion that on x-ray has a punched out

55:24

lytic lesion look. Um, and that's what we're seeing here.

55:29

And then when you go to mr, um, it can even have a soft tissue mass.

55:33

I've seen it with a soft tissue mass. It can look very, very aggressive,

55:37

but when you put it all together,

55:38

if you have a lesion with massive edema around it,

55:42

it should kind of make you think something inflammatory.

55:45

Infectious L L C H is kind of an inflammatory lesion. Um,

55:50

so that punched out lytic look,

55:53

you in sarcoma doesn't really look like that, right? Um,

55:56

sure you can have a metastasis if you have neuroblastoma, but that,

56:00

that benign periosteal reaction,

56:02

a smooth reaction tells you that it's most likely not gonna be a malignant

56:06

lesion.

56:07

So L C H is something that can present as a solitary bone lesion and,

56:12

um, punched out leg lesion.

56:14

And so it's important to suggest that because this is a very

56:19

sensitive area, parents, uh,

56:21

wanna know that there's a possibility it could be a benign thing. It's very,

56:25

very stressful for the parents and the families.

56:28

And so if you can suggest that it could even be L C H,

56:31

that's actually very helpful. Um,

56:33

because if we just say you in sarcoma,

56:36

the these guys are extremely depressed and,

56:39

and it might take weeks to get the biopsy and so it's very important to kind of

56:42

always think about L c h. Other questions

56:53

you describe the types of discoid in your report? Um, I usually,

57:00

I don't, I don't,

57:00

I don't really know the definite different types to be totally honest with you.

57:03

I do look for the berg variant, which I've never seen,

57:07

only in textbooks to see if you have, um, those, those attachments there. The,

57:12

the, uh, meniscal struts. I will kind of describe how big the meniscus is.

57:16

So if it's going all the way to the notch,

57:18

I'll make a point of saying that if it's just kind of a borderline discus uh,

57:22

discoid, I'll sort of say that as well. Um,

57:24

but then I also think it's important to describe if you see any tear,

57:27

if you see that intrasubstance, um, degenerative signal because that, um,

57:32

will kind of, uh, there's sort of, I think of that as like a little micro tear,

57:36

so they're probably more prone to tearing, um, as well

57:42

here. Okay, good. And so, um,

57:46

in pediatrics or bone lesions,

57:49

I think they're actually more fun than in the adult side because in adults any

57:53

lesion could be a metastasis. Uh, but in peds, um,

57:58

we get more of like the kind of real bone lesions.

58:00

But I amant so you can really use your, I have a whole other talk on, uh, on,

58:05

on pediatric, uh, bone lesions. But um,

58:09

you can really use your location and imaging findings to actually predict more

58:13

of the histology. Uh, okay, so tolo fracture versus, um,

58:18

versus, uh, tri plain. So tolo fracture is, again,

58:21

the best way to think of it is that it's an ion fracture,

58:24

so an evulsion fracture of the syndesmotic ligament.

58:29

So you have the, um,

58:31

syn ligament is gonna be pulling off the, um,

58:36

anterolateral corner of the tibial epiphysis. And so, um,

58:42

what we're seeing here is that this piece of a epiphysis uls off

58:48

and that produces a salt to Harris three fracture. So that's all,

58:51

it's a tri plaine is not an avulsion fracture, so it's,

58:55

it's a different fracture altogether.

58:56

You have basically a fracture in three different planes.

58:58

You have a vertical fracture through the epi epiphysis going through the isis

59:03

and on the lateral view the meta fracture. So it's three different parts to it.

59:07

Salter Harris four. Okay, going back to the leukemia case.

59:12

Um, when you first look at the marrow, um,

59:17

symmetry is, um, lemme, lemme go back here. Uh,

59:22

symmetry is not gonna help you as much in these cases. Very tricky.

59:28

Um, you want to get used to what normal marrow looks like.

59:32

So on a stir image,

59:33

if you just pull up a stir image from a case that you have currently in your,

59:36

in your, in your systems stir images, the marrow should be kind of grayish.

59:42

Um, you would never have a marrow that is like this, this bright. Um, if you,

59:46

if you compare that to cases you have, this should be, uh,

59:49

alarming When you go to the T one, um,

59:52

notice that the marrow is darker than adjacent skeletal muscle that is

59:56

concerning for a malignant process and then impedes.

60:00

The other hint you can do is look for areas that you expect to see fatty marrow.

60:05

So even if you're someone with just hyperactive red marrow or a lot of red

60:08

marrow, the epiphyses and the diaphysis usually are still fatty.

60:13

And so this is a red flag that you see, um,

60:17

dark epiphyses. So if you see dark epiphyses on T one,

60:21

that should kind of make you think that this is,

60:23

this is concerning for a marrow replacement process.

60:26

And I'm working on a technique, um, with, uh, fat fraction to basically,

60:31

um, be able to put a region of interest to actually give you a percentage.

60:34

So I have a paper in, uh,

60:36

peds Rad from a few years ago showing that if you do a fat fraction similar to

60:40

liver, uh,

60:41

you can actually get a number and typically leukemic cases are below 10%.

60:47

And so, um, if you have a ton of marrow infiltration,

60:50

the fat and the marrow will go down, down, down, down, down.

60:53

That's a way to kind of make it a little bit less subjective.

61:04

Cool. Um, okay, any other questions here?

61:08

We're just about over the hour. Thank you so much for your compliments.

61:11

Appreciate it. Uh,

61:13

happy to give more talks in the future if you guys would like. Um, these are,

61:18

um, hard cases. Pediatrics is definitely challenging. Uh,

61:22

but it's fun and uh, that's what I love.

61:25

So thank you guys for enjoying it. And so, um,

61:29

that's all I have today.

61:31

Thank you so much Dr. Sam.

61:33

Thank you so much for your interactive case review today. It was a lot of fun.

61:36

Um, and thank you to all of you for, uh, participating in our noon conference.

61:41

You can access the recording of today's conference and all our previous noon

61:44

conferences by creating a free m r I online account.

61:48

Be sure to join us next week on Thursday,

61:50

October 5th at 12:00 PM Eastern featuring Dr.

61:54

Alka Singal for a noon conference entitled role of Ultrasound and Pediatric

61:59

GI Emergencies.

62:00

You can register for this free lecture@mrionline.com and follow us on social

62:05

media for updates on future noon conferences. Thanks again and have a great day.