0:02

Hello, and welcome to Noon

0:04

Conference hosted by MRI Online.

0:07

In response to the changes happening around

0:09

the world right now and the shutting down of

0:11

in-person events, we have decided to provide free

0:14

Noon Conferences to all radiologists worldwide.

0:17

Today, we are joined by Dr. Douglas Katz.

0:20

Dr. Katz is the Vice Chair of Research at NYU

0:24

Langone Hospital in Long Island and Professor of

0:27

Radiology at the Long Island School of Medicine.

0:30

He has extensive experience in academic radiology.

0:34

A reminder that there will be a Q and A session

0:36

at the end of the lecture, so please use the

0:38

Q and A feature to ask your questions, and we

0:40

will get to as many as we can before time is up.

0:43

That being said, thank you all

0:44

for joining us today, Dr. Katz.

0:46

I will let you take it from here.

0:48

So, it's really a pleasure and honor to do this,

0:50

and it's actually nice to actually, although not in

0:53

person, in person, do something live for a change.

0:55

So, that's really appreciated.

0:57

I want to thank Dr. Jeanette Collins,

1:00

for organizing and asking me to do this, and

1:02

for Ryan Nelson for his technical support.

1:05

So, we're gonna spend the hour talking about

1:07

a topic that isn't necessarily my primary

1:10

interest in academics, but increasingly has

1:12

become a focus, and that's imaging of the

1:15

abdomen and pelvis with CT in the setting of

1:18

primarily blunt trauma, but we'll

1:19

touch a little on some things

1:21

that can come up in penetrating trauma.

1:23

But the main focus will be on blunt trauma.

1:26

And, you know, my part,

1:27

everybody's situation is different.

1:29

My particular practice situation, I'm in a tertiary,

1:32

not a quaternary hospital, which is part of a

1:35

big, now quaternary center and system.

1:39

And so, every once in a while things come through,

1:41

and this may be your situation as well, that you're

1:43

not necessarily at a very, very busy

1:46

trauma center and you get comfortable with seeing

1:48

these cases on a routine basis, but cases may come

1:51

through occasionally that are challenging, and there

1:53

are potential pitfalls and problems that are

1:57

not necessarily obvious in terms of dealing with.

1:59

We had an example of this just a few days ago.

2:03

I was on call last Saturday, and we had

2:06

something we rarely see, even at my center,

2:08

which was someone who had such severe trauma

2:11

that they went to the OR and then immediately

2:13

after an initial damage control surgery,

2:16

they got the CT, and it was really just a mess

2:19

in terms of the findings on that scan.

2:22

Very, very challenging.

2:24

So, in the next hour, we're gonna talk about some of

2:26

these pitfalls, potential pitfalls, and problems.

2:29

Some of them are relatively common, some are less

2:31

common, but they're things we need to be aware of.

2:34

We're gonna talk about some strategies for

2:36

optimizing technique to potentially reduce not

2:40

identifying them and not being able to see them

2:42

in the first place because of the CT acquisition

2:45

that was done.

2:47

And then we're gonna talk about search patterns.

2:49

As with everything in radiology, search

2:50

patterns are very, very important, of course.

2:53

And so, there are some themes that come up in terms

2:55

of what to look at when you're examining CTs

2:59

of the abdomen and pelvis in the blunt trauma setting.

3:02

Just some background.

3:03

So, diagnostic errors have been shown to

3:06

be preventable, as with a lot of scenarios

3:09

in a minority of cases, and this is true,

3:12

including in the trauma center situation,

3:15

and imaging isn't all of the problem,

3:17

but it certainly can potentially contribute.

3:20

So, things that may lead us down

3:22

the wrong path include using the wrong

3:24

technique from the beginning.

3:26

Of course, there are situations

3:28

where patients have overlying devices.

3:31

This is never an ideal scenario.

3:33

They may be moving, arms may

3:36

be at the side, et cetera, and even

3:38

despite the attempts of the trauma team

3:40

to get us the best quality CT, and our

3:43

technologists, it may not necessarily be possible.

3:46

The patient may be very large,

3:49

and there can be other inherent things that we just can't fix.

3:52

And then, to compound problems, we

3:55

may encounter variants in anatomy.

3:58

There may be pre-existent disease, and we may not

4:00

know about any of it, maybe no prior imaging.

4:03

And that can

4:04

further compound, again, correct interpretation.

4:08

There are some things that can be

4:10

physiologic that may mimic pathology.

4:14

And, uh, sometimes things are just

4:16

very subtle, uh, in the trauma setting,

4:18

and those can represent true misses.

4:21

Um, and then as with every other CT of, uh, any, you

4:24

know, scenario when it comes to the abdomen and pelvis,

4:27

trauma or non-trauma, we really should be routinely

4:29

looking at, uh, lung windows and bone windows in

4:32

addition to soft tissue windows, and looking carefully

4:34

for things that may, uh, indicate significant

4:37

pathology, although may not be particularly obvious.

4:41

Uh, so here's an example, and I

4:42

should give a little background here.

4:44

This was, uh, really a team project.

4:46

Um, you know, I, I think academic

4:49

radiology in particular is a team sport.

4:51

I'd like to think of it that way.

4:52

And so, uh, I had special help for, uh, this

4:55

presentation from two good colleagues and friends.

4:58

One was Jorge Soto, Chair at

5:00

Boston University in Boston.

5:02

And, uh, Michael Patlas in Hamilton,

5:05

Ontario, Canada at McMaster University.

5:08

And they contributed substantial expertise

5:10

and case material to this presentation.

5:12

So, this is from Mike Patlas up in Canada.

5:15

This was a 35-year-old man.

5:17

He had, uh, you know, blunt trauma, was assaulted, and

5:20

the resident on call preliminarily called this negative.

5:23

Well, it was negative for trauma,

5:25

but was, was not correctly identified.

5:27

And I think you can see it much better

5:29

on the sagittal lung window here.

5:31

To our right is that there's in fact a packet

5:34

of drugs in the rectum, which was overlooked.

5:37

And that was because a routine search with

5:39

lung windows was not performed, much more

5:41

obvious, uh, when you look with lung windows.

5:44

And so, any sort of gas or air-containing structure,

5:47

normal or abnormal, is gonna be, in general, more

5:50

readily identified when we look at lung windows.

5:53

So, just sort of a reminder, uh, even in the

5:55

trauma setting where things can be crazy, there

5:57

can be multiple exams you have to interpret.

6:00

Um, you may be, you know, these cases tend to

6:02

come in in the middle of the night, uh, after

6:04

hours when we're least well-staffed and busiest.

6:08

Uh, and things are most stressful.

6:10

Uh, it's easy to forget the basics.

6:13

Um, and so, leading to that, you know,

6:15

that's just the nature of things.

6:16

Even at, you know, quote, Level One trauma

6:18

centers in the US, Canada, and elsewhere.

6:21

Uh, this is when these folks come in.

6:23

And quite honestly, it, it, you know,

6:25

unless you're always up after hours, uh,

6:29

most of our, uh, emergency radiologists,

6:32

they're, they're shifting, right?

6:34

They're not always doing the overnight

6:35

shift and staying up every night.

6:37

Even when they're not working, they go back and forth.

6:39

It's like flying to, you know, Japan or Australia

6:42

every, uh, you know, second or third week and back.

6:45

Uh, and so, you know, you're not gonna be as

6:48

sharp at, at three in the morning if you, uh,

6:50

just shifted to that particular shift, uh,

6:53

a day or two before compared with, you know,

6:55

say, at nine in the morning, and you've

6:57

had your cup of coffee, and you're fresh.

6:59

Uh, so, again, maintaining a consistency of

7:01

search pattern, repetitively looking for the

7:04

same things, being aware of the pitfalls you

7:07

can run into, can help to reduce these errors.

7:09

Again, one of my favorite statements is

7:11

"The eye does not see what the mind does not know."

7:14

So, if you don't know to look for some

7:16

subtleties and some potential things, you're

7:18

not necessarily gonna readily identify them.

7:22

Um, one of the other concepts here, in terms

7:24

of search pattern, is that you may see

7:26

one injury that may be obvious, and then you

7:28

may overlook the fact that there are other

7:31

injuries that are not quite as obvious.

7:33

So, in the setting of blunt trauma, and also

7:35

in penetrating trauma, um, there are packages.

7:38

You have injury to one organ and structure,

7:41

and you may have adjacent injuries, which again

7:43

could be obvious, but may be a little bit more subtle.

7:46

So, here's a so-called right package.

7:48

This is someone who, uh, has a, you know,

7:51

obvious, uh, complex hepatic laceration.

7:54

Uh, but there's also an acute right

7:56

adrenal hematoma here in the middle slide.

7:58

And then we have also injury to the right kidney.

8:01

Now, I'm not gonna spend time, uh, because

8:04

we could literally spend, you know, a whole

8:05

seminar on imaging of trauma, including of

8:08

the torso in particular, in various settings.

8:10

So, I'm not gonna go into detail into what's

8:13

called the AAST Classification System for trauma.

8:17

Uh, but at least in the US, and I think in Canada

8:19

as well, maybe other places, we are now mandated.

8:22

Uh, to use that system to categorize, uh, the

8:26

nature of injuries, and even if it's not the

8:27

most accurate system, in 2018 it underwent a

8:31

very, uh, substantial revision, uh, including

8:34

the presence or absence of active bleeding,

8:38

uh,

8:38

pseudoaneurysm formation, and arteriovenous

8:41

fistula formation, or some combination of those.

8:43

And we'll, we'll touch on this in terms

8:45

of looking for those injuries in a minute.

8:47

Uh, but we are, at least in my center, and I

8:49

think most centers that are accredited by the

8:52

surgical bodies at the national US level,

8:55

uh, are mandated to include those in the reports.

8:58

And again, it's something we often forget.

9:00

Uh, I receive, uh, you know, communications

9:02

on a monthly basis about, uh, cases that just

9:05

didn't get, uh, clarified as such and qual,

9:08

uh, classified as such because, you know, again,

9:10

we may only see these cases occasionally, the

9:12

attending is on, on call, is very busy.

9:15

They forget, the resident forgets, et cetera.

9:17

So again, the theme here is injury

9:19

packets, look for, uh, multiple injuries.

9:21

Once you see one thing, there may be

9:23

frequently other things.

9:24

So, here's another sort of packet.

9:26

This is a classic, uh, association.

9:29

We see the Chance fracture in the middle

9:31

slide there, sort of a shearing injury

9:33

through, uh, the upper lumbar vertebra.

9:35

And then there is, in this case, fairly apparent

9:38

injury to the, uh, small bowel in the vicinity

9:41

that can also be associated pancreatic injury.

9:44

And sometimes those injuries can be subtler

9:46

than the musculoskeletal injury.

9:49

So again, having these on your radar in

9:51

terms of searching for them is very important.

9:54

Uh, let me just make a quick comment about

9:57

a search pattern because I think you can be very

10:00

easily overwhelmed again by these trauma cases.

10:02

Like the case we had last Saturday.

10:04

There's so many things going on, it may

10:06

be very difficult to know where to start.

10:09

And so,

10:10

you know, everybody's approach is different,

10:11

but my particular approach and recommendation

10:13

is, uh, to start with a coronal plane.

10:16

It's rare that I usually do primary coronal

10:19

interpretation with most things, but I, uh,

10:22

preliminarily will look at the coronal images.

10:24

If it's a chest, abdomen, and pelvis, hopefully

10:26

they'll come over as one, uh, contiguous

10:28

acquisition, at least for the, you

10:31

know, arterial and portal venous phases.

10:33

If we do those, we'll talk about that in a little bit.

10:35

And then just quickly look, ideally you're in the

10:38

actual CT scanner, that may not be realistic, but

10:41

the ideal world is that you're in the CT scanner

10:43

while these images are coming

10:44

up, you're monitoring them.

10:46

The trauma team or somebody from the trauma team

10:48

is there, and you're communicating immediately

10:50

obvious significant injuries such as diaphragmatic

10:53

disruption, if it's an obvious one, active

10:55

bleeding, pneumothoraces, things that someone

10:57

needs to do something about immediately, and then

11:00

you can go and do a more detailed search after the

11:02

initial communication, as opposed to waiting to do

11:05

the communication after you've done your full report.

11:09

So, in terms of, uh, you know, errors,

11:11

again, going back to the general

11:12

concepts here, we often have no history.

11:15

The history is usually trauma.

11:17

You know, I have to pick, talk in person, or get

11:20

on the phone and talk to the emergency department,

11:22

the trauma team, say, "Okay, is this someone

11:24

who stubbed their toe, or is this someone

11:26

who fell out of a three-story building?"

11:28

Um, and where is there apparent, you know, hematoma?

11:32

Where is the patient hurt?

11:33

If you get that information, where am I looking?

11:35

Especially in these lower velocity traumas.

11:37

And more and more we're seeing

11:39

older people who fall, or people who are, you know,

11:43

intoxicated, inebriated, whatever, and they fall.

11:46

We may get limited histories.

11:48

Um, uh, but if we can get information

11:50

where to refine our search in terms of

11:52

looking for subtle injuries, very helpful.

11:55

Looking for subtle contusions, or sometimes not so

11:58

subtle contusions or bleeding, uh, in the cutaneous

12:01

and subcutaneous tissues helps us to then look

12:03

for potentially more subtle underlying injuries.

12:06

Advanced age and sedation, again, well-demonstrated

12:09

to be associated with higher injury rates.

12:11

And again, the tricky thing with some of these

12:13

falls is that you may think, well, it's not, you

12:15

know, a high-velocity motor vehicle collision,

12:18

what's there gonna be?

12:19

But there is definitely the potential for

12:22

significant injury, uh, in these individuals.

12:24

And we, so we have to not be cavalier about

12:27

it and really carefully, uh, search, uh, for

12:29

pretty much every trauma that we examine.

12:32

The other major challenge is that, you know,

12:34

especially if you're at a, you know, Level One trauma

12:36

center, quote unquote, you may have no prior imaging.

12:39

The patient may have been sent in

12:40

from a regional center, local center.

12:43

They may have been scanned, and

12:44

we may not have access to those.

12:45

We may not have much information

12:47

about what is on those.

12:48

And in fact, there's an entire body of

12:50

literature in the emergency radiology and

12:52

trauma surgery literature on this exact scenario

12:56

where, you know, how do you handle that?

12:57

How do you get the outside films?

12:58

How do you look at them?

12:59

When do you re-scan, you know, how do

13:02

you put the information in your, in your

13:03

PACS and informatics systems, et cetera.

13:07

So, now let's talk about, uh, technique.

13:09

Again, technique is important.

13:10

There are some areas that people agree on

13:12

and some areas where there's controversy.

13:14

So, at least in the blunt trauma setting

13:17

for the abdomen and pelvis CT imaging, uh,

13:19

pretty much everybody agrees at this point.

13:20

Oral contrast is a no-no, it's a waste of time.

13:24

Uh, it, it really is not gonna add much.

13:27

The yield is very minimal in terms of

13:28

seeing upper GI tract, um, you know, injury.

13:32

And it, it, and, you know, occasionally

13:34

you could risk aspiration.

13:36

So, that's a no.

13:37

Um, the golden hour of trauma really demands

13:40

that we get imaging done as quickly as possible.

13:43

Ideally, a good intravenous access

13:45

given at a relatively fast rate.

13:47

Again, in an ideal world, we would be like,

13:51

we would just scan over and over and over

13:53

again and there would be no radiation penalty.

13:55

We could just scan non-contrast, early

13:57

arterial, late arterial, early portal venous,

14:00

on and on delays, and, you know, get, you

14:03

know, 15 series like we do for a liver MRI.

14:05

But that's not realistic in this setting.

14:08

So, we can apply lower radiation dose.

14:11

The principle here is to not

14:14

compromise diagnostic quality.

14:15

We want to go low, you know, how low can you go

14:17

but still get, uh, information out of the images.

14:21

Um, and that's more so for the ancillary

14:24

acquisitions, which we'll talk about.

14:25

Of course, with pretty much everything we're

14:27

getting routine coronal and sagittal reformats, and

14:29

probably more advanced reforms in some scenarios.

14:32

Um, for me, uh, I generally rely on the

14:36

axials for my then, you know, further,

14:38

more detailed primary interpretation.

14:40

And then I'll look at the coronals, of course, for

14:42

the spine, but it's also helpful for the bowel.

14:44

And every once in a while, I, I, you know,

14:46

I do get information out of the sagittals in

14:48

terms of displacement of vertebrae, or if we

14:51

were doing chest imaging for sternal fractures.

14:54

Definitely, sagittals are my

14:55

key, uh, sequence for that.

14:57

But then the question is, how many phases

14:59

and, and how exactly do you do it?

15:01

And here's where the debate begins.

15:03

Um, and we'll talk about this.

15:05

I think everyone is certainly

15:06

in concordance at this point.

15:07

If you're concerned about a bladder injury, you

15:09

really can't just, you know, do delayed images.

15:12

You have to challenge the bladder

15:14

and do a dedicated CT cystogram.

15:16

You can, of course, do fluoroscopic cystography, but

15:19

typically in this setting, we're doing it at the time

15:21

or shortly after the initial acquisitions with the CT.

15:25

So, everybody agrees if you're, you know,

15:27

looking in the trauma setting, in the blunt

15:29

trauma setting, uh, that you're gonna be doing

15:32

a portal venous phase, um, for the abdomen.

15:35

And that's really a critical initial acquisition.

15:38

But it's not good enough compared with, say,

15:40

you know, routine imaging of the acute abdomen.

15:42

And that's not good enough.

15:43

You're really,

15:44

it's been shown by multiple studies,

15:46

uh, over the last 15, 20 years.

15:48

Now, the emphasis from this has come

15:50

from the University of Maryland group.

15:52

Um, in terms of other, other groups showing

15:55

that you're gonna miss stuff if that's all

15:56

you do, and we'll show some cases of that.

15:59

So, how much do you do?

16:01

Well, um, ideally in the upper and mid abdomen,

16:04

you're gonna do, um, especially if there's

16:06

mechanism, you're gonna do a late arterial

16:09

phase in addition to the portal venous phase.

16:12

And then you may wanna do a second look.

16:13

And this is where if you have the luxury of being

16:15

able to look at these real time or very, very shortly

16:18

after the image acquired, you can do delayed imaging.

16:21

Again, reducing the radiation dose if

16:23

possible, to characterize what's going on.

16:26

Is there active bleeding?

16:27

Is there a pseudoaneurysm?

16:29

Um, is there GU tract injury?

16:32

And particularly in that, you know, five- to ten-minute

16:35

or even later delayed phase, um, determining the

16:38

nature of urinary tract injury, if there is any.

16:41

Uh, and so again, we can reduce

16:43

the dose for those phases.

16:45

So, here's an example from Mike Patlas.

16:46

This is a case where there's obviously

16:49

substantial right perinephric hematoma

16:52

and also urinoma.

16:54

It's probably a mixture of the two.

16:56

And so the question is, is there also renal

16:58

collecting system, proximal ureteral, or both injury?

17:01

And the answer is yes.

17:03

We do have a proximal ureteral injury.

17:05

And so, uh, no surprise given how much

17:08

there is around that right kidney

17:09

that the delayed images would show.

17:11

Um, active extravasation.

17:13

Again, this is gonna make a difference in terms

17:15

of management, in terms of some other things.

17:18

Here's a case where it was tricky to characterize

17:21

the exact extent of this right renal injury.

17:25

There is some perinephric hematoma and

17:27

possibly urinoma, and it was tough to grade this

17:31

just on the basis of this

17:33

portal venous phase image alone.

17:35

So, a delayed image here, in this case

17:37

obtained two hours later, shows that, in fact,

17:40

there is an injury to the renal pelvic junction.

17:43

There's extravasation of opacified urine, and this

17:46

upgrades the AAST grade, but more importantly,

17:49

may potentially change patient management.

17:53

Here's a case from Mike Patlas, which I think

17:55

is very challenging, and this is where

17:58

the easier cases may be on

18:00

the straightforward side, but once you

18:01

start having multiple things going on,

18:03

it could be tough to sort them out.

18:06

So, here's a 24-year-old woman after a

18:08

motor vehicle collision, and you first

18:10

look at this, you're like, oh my goodness.

18:11

There's all sorts of things, you know, abnormal here.

18:14

So, you have to sort of break it down, and unfortunately

18:16

you have to kind of break it down fairly quickly.

18:18

So, there's a lot of periportal edema, there's

18:22

ascites here, at least a lot of internal edema.

18:26

There's injury here on this

18:28

lower right image to the

18:30

left kidney, and we see shock bowel.

18:33

This is someone who's

18:34

significantly in trouble.

18:37

This bowel is markedly

18:39

thickened, as you see, it's distended.

18:41

Um, and interestingly,

18:43

there's oral contrast on board.

18:45

It's an older case, and we wouldn't

18:46

again do this currently.

18:48

And then this image on the left shows

18:50

these structures that were circled, which were

18:53

erroneously thought in the initial interpretation as

18:56

being ureters, but in fact, they're the gonadal veins.

18:59

They're not the ureters at all.

19:01

So, what happened here, again, lots of stuff going on.

19:04

The patient became anuric, and they

19:06

actually did a radiograph.

19:08

That's a cone-down of that.

19:10

Radiograph four hours later.

19:12

And you can see the urine is actually

19:15

extravasated from both ureters,

19:18

into the retroperitoneum, right

19:21

more than left.

19:22

And this is in association with a fracture

19:26

of the L3 vertebral level.

19:29

So, there's proximal ureteral slash

19:32

UPJ disruption bilaterally,

19:35

in this patient, which was unanticipated.

19:38

And again, it's very easy to overlook these

19:40

urinary tract injuries because we may not

19:43

necessarily know or remember to get delayed

19:46

imaging, and it may not be the focus.

19:48

We can be distracted by the initially potentially

19:51

life-threatening injuries, the things that are

19:53

actively exsanguinating or disrupted, and

19:57

miss the fact that there are other things that have

19:59

implications, maybe a little bit later on,

20:02

but would be ideally identified

20:05

at the initial interpretation.

20:07

Um, if you're interested, there was an article

20:09

we did a few years ago, um, on why do we

20:14

miss, uh, ureteral injuries, and we published

20:16

that, I believe, in Emergency Radiology.

20:18

So, there's a whole body of

20:20

literature on that specific issue itself.

20:23

So again, I mentioned the AAST, um, has

20:27

relatively recently finally acknowledged the fact

20:31

that it isn't just the extent of an organ injury and,

20:35

you know, is it involving the collecting system,

20:38

if it's kidney, uh, or not.

20:40

And I should say again, I, I have

20:42

enough useless information in my head.

20:44

I, I hate memorizing classification systems.

20:46

Um, it's so easy now to just, you know, click

20:49

in a few seconds and you go to the AAST's website.

20:53

We actually have had, until recently,

20:55

the classification systems on our PACS.

20:58

So, you just have to click a button and you,

21:00

you know, in the setting of, okay, let me see.

21:02

I don't remember the grading

21:04

system for pancreatic injury with CT.

21:06

Let me bring it up, and then you

21:08

can put that in your report.

21:09

Uh, so again, they finally

21:12

acknowledged that in their revision.

21:14

So, active extravasation, and we're talking

21:16

about generally arterial, but every

21:17

once in a while venous, is not contained.

21:21

Um, the morphology and size will change on serial

21:24

imaging, and that's why it's, again, very important

21:25

to at least do two phases when imaging the upper and

21:28

mid abdomen, particularly for the liver and spleen, and

21:31

the attenuation is usually greater than the aorta,

21:33

because the aorta is gonna wash out, but the

21:35

contrast in the blood that's going somewhere it

21:37

shouldn't, is gonna remain on the dense side.

21:41

A pseudoaneurysm is contained.

21:43

There's no change in morphology on the delayed images,

21:46

and the attenuation should be the same as the aorta

21:48

and other central arteries on all phases of imaging.

21:52

So, here are two cases to compare and contrast,

21:54

and you can see they're both significant injuries.

21:57

Uh, the case on our left, there's substantial per

22:00

splenic hematoma, but there's also what they call, the

22:03

surgeons like this, vascular blush in the spleen.

22:08

There's a similar small vascular blush in the spleen

22:10

on this case to the right, a different patient.

22:12

You can see the hint as to which one

22:15

is the more immediately urgent

22:17

one is the fact that there's an obvious

22:19

major, major spinal injury here, and there's

22:22

other findings, uh, there's, you know,

22:24

peridiaphragmatic hematoma, et cetera.

22:26

Um, and so, that's the portal

22:29

venous phase for both these cases.

22:30

Delayed images a few minutes plus out

22:34

show that the area of hypervascularity

22:37

in the case on our left is washed out, so

22:40

that's consistent with a pseudoaneurysm, whereas

22:42

the case on our right, in contrast, we see

22:45

heterogeneous residual high-density material

22:47

that has spread out, um, in the spleen.

22:50

So, this is not contained, it's not a

22:52

pseudoaneurysm, or at least not only a

22:54

pseudoaneurysm, it's active bleeding.

22:57

And so, that needs to be

22:58

urgently managed.

23:00

Not to say the case on our left doesn't need

23:02

potentially urgent management, but certainly

23:04

the one on the right is the more emergency

23:07

kind of case here, as a patient where if

23:12

we only had the, in this case, portal venous

23:14

and delayed images, we see heterogeneity of the

23:17

spleen, we see some focal areas of low density.

23:20

But it's sort of hard to characterize

23:21

what are these exactly?

23:23

There's a little bit of perisplenic hematoma.

23:26

Um, whereas on the arterial phase and then the

23:29

corresponding MIP, we see there are actually

23:31

multiple areas that are just not normal.

23:33

This is not the typical tiger

23:36

striping appearance of the spleen.

23:37

These are focal, multiple pseudoaneurysms,

23:41

which we also see in the MIP image.

23:42

So, again, having, in this case, the

23:44

three-phase CT is very, very useful.

23:47

And certainly, the radiation, you know,

23:49

dose is not the major concern here,

23:50

obviously, when we're dealing with

23:52

potentially life-threatening injuries.

23:54

Here's a case from Mike Patlas.

23:56

An 18-year-old struck in the left flank during a

23:58

sporting event that he was participating in.

24:02

And there's, you know, of course, substantial

24:04

contusion here in the anterior spleen.

24:07

But on the initial portal venous phase

24:10

image, it wasn't appreciated that there's, in

24:11

fact, an underlying arteriovenous fistula.

24:16

So, the patient was brought back, re-scanning.

24:19

And you can see the fact that

24:21

there is early enhancement on this.

24:24

Uh, I think it's a MIP image of the central

24:28

splenic vein indicating that there's an associated

24:32

arteriovenous fistula in this vicinity.

24:34

So, I would say, you know, AV

24:35

fistulas are certainly not common.

24:38

Uh, but we do occasionally see them, and we do

24:40

occasionally see them in the blunt trauma setting.

24:46

So, uh, again, everybody has different

24:48

protocols, and you could do a whole

24:50

seminar on the issue of, you know, how

24:54

should we be scanning the abdomen and pelvis.

24:56

And we've actually done this at the RSNA and the

25:00

American Society of Emergency Radiology annual meetings

25:02

and others, where we put a bunch of folks on the

25:04

podium from major trauma centers in the US,

25:08

Canada, and elsewhere around the world, and say, okay.

25:10

You know, what do you do in

25:11

each of these scenarios?

25:13

And you would get somewhat different answers.

25:15

You know, do you do a whole-body CT?

25:17

The trend over the last 10 to 15 years

25:19

has been, in patients who have mechanism or

25:22

have, you know, injuries just on initial

25:25

assessment that are consistent with

25:27

substantive injuries, to do a whole-body CT.

25:31

But then the debate comes, you

25:32

know, exactly how do you do that?

25:34

How do you scan from, you know, top to bottom,

25:37

to get the maximum information that

25:39

you need without, you know, doing excessive

25:41

radiation in getting that information.

25:44

So, I'll at least show some examples from

25:47

Jorge Soto's group of what they had been doing

25:50

and what they had been doing more

25:52

recently in terms of how to maximize assessment.

25:55

So, if it was a torso trauma question,

25:58

they were initially doing a CTA of the chest, as we

26:01

see here, and then they were getting a contiguous

26:06

abdomen and pelvis during the portal venous phase.

26:09

So, say, you know, 65 to 80 seconds out from

26:12

the start of IV contrast administration.

26:14

And then if necessary, based on monitoring

26:17

mechanism, they were doing delayed acquisitions.

26:20

Again, could be at two minutes, could

26:22

be at 10 minutes, depending on what

26:23

they're seeing, what the mechanism is.

26:26

Uh, so for example, if there's, you know,

26:28

substantive injury, obvious, if there's an

26:31

initial radiograph of the pelvis showing, you

26:34

know, fractures, that's definitely an indication

26:37

where you're gonna probably do multiple

26:39

phases. I would probably do, you know,

26:41

at least three phases in that scenario.

26:44

Um, I would do portal, you know, the arterial

26:47

phase, looking for active bleed, extravasation,

26:50

pseudoaneurysms, because those are certainly

26:52

possible in the pelvis in that setting.

26:54

A portal venous acquisition, and then a delayed

26:56

acquisition to further assess what's going on.

26:59

And also to look for urinary tract injury,

27:02

and then possibly even a, you know, a

27:03

cystogram very likely in that setting.

27:05

So, it could be even four acquisitions.

27:08

But the problem is, I mentioned, is that you're

27:09

gonna potentially miss, in this situation,

27:12

characterization of injuries in the upper and mid abdomen.

27:14

So, what they have done

27:16

in the more recent years, and again,

27:18

they have a series of protocols just like we do,

27:20

and it depends on the particular mechanism, what

27:23

they're dealing with and what radiography shows.

27:25

And again, if you have the luxury of someone to tell

27:27

the CT technologist and talk to the trauma surgeons,

27:30

um, right before you're doing it, or while you're doing

27:33

it, to modify on the fly, they're doing the CTA but

27:37

continuing into the upper and mid abdomen, so they get

27:40

this late arterial look at things, and then doing the

27:44

full abdomen and pelvis in the portal venous

27:46

phase, and then, if necessary, the more delayed images.

27:50

So, it's been known for years that it

27:53

isn't good enough to just clamp a Foley,

27:55

wait 10 to 15 minutes with the patient on the CT

27:58

table, and get delayed images through the pelvis.

28:01

You certainly may see occasionally

28:03

injuries, but it's not adequate.

28:05

You have to challenge the bladder with contrast under

28:08

pressure, and certainly a case like this, you, you,

28:11

you're gonna, you know, there's gonna be high risk.

28:13

I mean, you have multiple pelvic

28:15

fractures just on the single left image.

28:17

You have a characteristic pattern,

28:19

so-called molar tooth of extraperitoneal.

28:23

Everybody forgets about the

28:24

extraperitoneal space, right?

28:25

We know about intraperitoneal, and we know about

28:28

retroperitoneal, but this is extraperitoneal.

28:31

The perivesical, prevesical, or paravesical

28:33

spaces has hematoma in it, and it's

28:36

causing that classic pear-shaped bladder.

28:39

And so right off the bat, even though you

28:41

know, you don't see an obvious bladder

28:42

disruption, there's a Foley in place.

28:44

It's high risk and high suspicion, and

28:47

the CT cystogram shows that there's

28:49

a relatively subtle disruption of the

28:51

anterior right aspect of the bladder.

28:53

So again, the importance of thinking about it,

28:56

um, if the trauma team doesn't ask for it and

28:59

you didn't do it, and there are other features

29:02

that, uh, you think put the patient at high risk,

29:05

uh, discuss with them the fact that you may need

29:07

to either do it with the patient still there, or

29:10

bring the patient back, or shortly thereafter.

29:11

Again, it may not be the top priority.

29:14

They may have to stabilize other injuries,

29:16

uh, but it's something to, uh, consider.

29:18

And here's another example of that 57-year-old, uh,

29:22

open book fracture, which I haven't shown on these

29:24

images, but, uh, the, uh, bladder just

29:29

partially filled with opacified urine from the initial

29:32

acquisition on delays just doesn't show the image,

29:35

the injury, although there is, again, suspicion based

29:37

on the pelvic fracture and the perivesical hematoma.

29:41

And so that was the initial image, and the image in

29:43

our middle and on our right shows a substantive

29:47

uh, disruption of the bladder, uh, here, which

29:51

is extraperitoneal going inferiorly and anteriorly,

29:54

uh, with the dedicated CT cystogram, with the

29:56

defect here well demonstrated as a general theme.

30:00

There was a paper from, oh, it's probably 20,

30:02

25 years ago from the group at Michigan, which

30:05

showed that in the blunt trauma setting, if

30:07

you have absolutely no fracture and absolutely

30:09

no perivesical or pelvic fluid or hematoma,

30:14

that your yield is gonna be pretty much zero.

30:16

So no, no coincidence or surprise that the

30:19

cases I've shown you, where there is evidence

30:21

of injury, uh, there, uh, you know, were

30:25

associated injuries to the bladder, but this

30:27

one I think is not quite as straightforward.

30:29

You know, there's a little bit

30:30

of fluid in the dependent pelvis.

30:31

It's a, um,

30:32

we'll talk about that phenomenon a little bit.

30:34

There's some gas or Foley, and there were

30:36

pelvic fractures, again, putting the patient

30:38

at risk, um, which I haven't shown you.

30:41

And this was following a motor vehicle collision.

30:42

And so then the subsequent CT cystogram shows,

30:45

in this case, intraperitoneal bladder rupture.

30:48

Um, scenarios where you see this, you can have, uh,

30:51

you know, one sort of classic story is someone

30:55

who has, uh, been drinking, they have a full bladder

30:58

'cause of the diuretic effect of the alcohol.

31:01

The alcohol leads to, or contributes

31:03

to the motor vehicle collision.

31:04

They hit a tree or something, and boom, the

31:07

bladder, which is an area

31:09

of inherent, you know, somewhat weakness,

31:12

ruptures, and you have intraperitoneal rupture.

31:14

But in fact, it can be tricky.

31:15

We had a case that came to quality assurance a

31:17

few months ago, and the surgeons were upset that

31:21

we didn't, and the urologists, that we didn't

31:23

exactly characterize the nature of a bladder

31:26

injury as being intraperitoneal versus, uh, you

31:29

know, extraperitoneal, uh, retroperitoneal.

31:32

And in fact, I looked at the case retrospectively,

31:35

some of my colleagues did, and we go,

31:36

uh, it's probably a combination of both.

31:38

And in fact, the data shows that

31:40

that's a fairly, uh, common scenario.

31:43

And so it may not even be that straightforward.

31:45

Uh, there are some differences in terms of management,

31:48

but, um, it's a case-by-case sort of determination.

31:52

So in terms of, you know, what are we recommending,

31:55

again, there's some debate, but we think you,

31:56

you know, absolutely everybody needs a portal venous

31:58

phase of a full abdomen and pelvis if there's mechanism,

32:01

if there's radiography showing significant injury.

32:04

There's concern for significant

32:06

injury, you're gonna do more than that.

32:08

Ideally, you're gonna, uh, want at least an arterial

32:12

or late arterial phase of the, uh, upper and mid

32:15

abdomen if there's a specific concern, a mechanism for

32:19

pelvic injury, you really want the arterial phase of

32:21

the entire abdomen, pelvis, not just the upper abdomen.

32:24

And then you're often gonna do delayed imaging

32:28

for characterization of bleeding, uh,

32:31

characterization of, um, you know,

32:33

upper and mid urinary tract injury.

32:36

And then you may actually wanna do a CT cystogram for

32:41

indications such as, you know, blood at the meatus of the

32:45

urethra, pelvic fracture, gross hematuria, et cetera.

32:47

And again, the radiation is

32:49

not the primary concern here.

32:52

Uh, so here's an example of, you

32:53

know, some of these pitfalls.

32:54

The patient who had obviously major injury,

32:57

we see, uh, you know, right adrenal hematoma.

33:00

There's, uh, uh, a concern here for aortic

33:03

injury 'cause of the paraortic hematoma in

33:05

the chest, and those are substantive enough.

33:09

And then you have, uh, you know, major

33:10

fracture to the right pelvis with lots of

33:13

hematoma and an area of active extravasation.

33:17

So that became the priority, uh, as opposed

33:20

to looking for a urinary tract injury.

33:22

Uh, and, uh, they still did do a CT cystogram

33:27

and it didn't show any bladder injury, but they

33:29

didn't do delays of the full abdomen pelvis.

33:32

So the priority, again, is

33:33

the active arterial bleeding.

33:35

Here's a SO image from the selective angiogram.

33:37

They embolized that pelvic bleeder and

33:40

patient was doing okay, and a few days later,

33:42

wasn't doing so great.

33:44

And the follow-up CT shows a lot of, uh, fluid that

33:48

looks simple density as opposed to blood.

33:50

In addition to the, uh, preexistent injuries, as

33:54

noted, and delayed imaging through this CT shows,

33:57

in fact, a proximal right ureteral disruption.

34:01

Um, and so that explains all this

34:03

additional fluid, which is urine.

34:05

So again, it, it, it can be very tricky to

34:07

sort these out when there's multiple complex

34:10

injuries, um, in the setting of trauma.

34:12

In particular. Uh, let's now talk about some

34:15

anatomic variants, which can be, uh, problematic.

34:19

Uh, we see splenic clefts

34:20

every hour of every day, right?

34:22

Anybody who reads, you know,

34:23

abdominal CT, MR, you see them.

34:26

And so they're not an issue in the

34:28

non-trauma setting, but they can be a

34:30

source of confusion in the trauma setting.

34:33

Um, clefts generally are well

34:36

defined, linear, and medial.

34:37

A true laceration may be somewhat irregular, and

34:41

there should generally be some evidence of injury

34:44

to the spleen itself or perisplenic edema, hematoma.

34:48

But there are certainly cases

34:49

where you just can't tell.

34:51

So these are two different patients, the patient on.

34:54

Again, we wouldn't give oral contrast.

34:55

Again, these, some of these are older cases.

34:58

Uh, this ends up being a, uh, a cleft, although

35:02

it really looks very similar to this in a

35:04

different patient, which ends up being a lac.

35:07

Uh, and you know, the clue again,

35:09

is there is some, uh, hematoma here

35:12

around the liver and spleen on the lower images.

35:14

There's certainly a, uh, liver, a laceration,

35:18

uh, but I think it can be very tough to

35:20

sort those out on a case-by-case basis.

35:24

So one of the other concepts that came, that

35:27

comes up is what are the things that we know

35:30

we're going to frequently miss on imaging

35:33

of the abdomen and pelvis in, um, both the blunt

35:38

as well as the penetrating trauma scenario.

35:40

And these are significant, uh,

35:43

misses, but we know they happen.

35:45

And this has been demonstrated over and over again.

35:47

And here's, uh, one paper from a, you know, 10

35:50

years ago from the trauma literature showing,

35:52

you know, an audit of, of this sort of thing.

35:54

And these are what they found. No surprise

35:55

whatsoever to those experienced in

35:58

um, emergency imaging with trauma.

36:01

So those include, and again, the key thing here

36:03

is to, when you're, you know, finalizing your

36:06

report, when you're doing that last look, carefully

36:09

look through, you know, in your mind, think, okay.

36:11

The things I know I could be missing are

36:13

diaphragmatic injury, pancreatic injury,

36:16

particularly bowel and mesenteric injury.

36:18

Those can be very, very challenging,

36:20

even for experienced radiologists

36:22

to sort out, unless it's obvious.

36:24

And then, you know, vascular injuries,

36:26

which sometimes can be on the subtler side.

36:29

One of the potential pitfalls, and this is

36:31

someone who was, uh, not in the trauma setting.

36:35

Uh, this was someone with significant pancreatitis

36:37

and peripancreatic necrosis, but just to show

36:40

something that can happen in the trauma setting.

36:42

This is the so-called hypoperfusion complex.

36:45

The cava is very flat.

36:46

There's a bowel that's a bit

36:48

more edematous than it should be.

36:50

The jejunum normally has prominent folds,

36:52

but this is a bit more than normal.

36:54

Um, and so there are a host of things described

36:56

in this setting, uh, dense, uh, adrenals, you

36:59

know, flat cava, small caliber aorta and central

37:02

vessels, small renal veins, hyperenhancement of

37:05

the pancreas and kidneys, those sort of things.

37:07

It's, uh, loss of autoregulation.

37:09

The bowel becomes, uh, denser.

37:11

The contrast gets in and, and it can't get out.

37:13

It's sort of like that old sort of, maybe it's

37:15

an unfortunate reference around lunchtime, but

37:18

uh, roach motel, there was that product, you

37:20

know, the roaches get in and they can't get out.

37:22

Well, it's, the contrast gets in and it can't

37:24

get out because of loss of autoregulation and

37:26

other complex, uh, hemodynamic perturbations.

37:30

One of the important concepts, and I've alluded to

37:32

this already, is the, uh, finding of a small amount

37:35

of free fluid in the dependent peritoneal cavity.

37:37

So, you know, the, the, the, the teaching used

37:40

to be males don't have free fluid in the pelvis.

37:42

If you see free fluid, it indicates,

37:44

you know, potentially substantial injury or

37:47

is it's okay to have that in, in females?

37:49

Well, not necessarily true.

37:52

So, um, and, and in fact we see this

37:55

occasionally in the non-trauma setting and it's

37:57

attributed to a little bit of third shifting,

38:00

someone getting a lot of IV fluids and.

38:03

Um, and so there've been a couple of papers on this.

38:05

This first one was from J. Soto's group some years

38:08

ago, and they looked at almost, uh, 600, um, uh,

38:11

600, it was 670 males in the blunt trauma setting.

38:15

It was seen in about 3%, and it was

38:18

simple water, and zero had bowel injury.

38:20

The group at University of, uh, uh, Virginia, uh,

38:23

Commonwealth University, Joe Yu, uh, looked at a

38:27

thousand, uh, males in the blunt trauma setting,

38:30

and it was about 5% had some fluid all below

38:32

the level of S3, simple water, zero bowel injury.

38:36

So this can happen.

38:37

It, it is something that would raise a red

38:39

flag, but isn't necessarily something that's

38:41

going to change management substantially.

38:45

Um, and so, you know, when I see this, and I

38:48

see this occasionally in males who are just.

38:50

Getting a lot of IV fluids for

38:52

unrelated, you know, not trauma reasons.

38:54

And I'll say, okay, how much fluids are they getting?

38:56

And they, oh, they're getting a hundred and,

38:58

you know, 50 cc of normal saline an hour.

39:00

Well, if you can, you may want to back off a

39:03

little bit because they're starting to third space.

39:05

So here's exactly the sort of scenario.

39:08

Obviously there are other things going on here, but,

39:10

uh, this, uh, was simple water, no bowel injury.

39:13

And sometimes there's concurrent

39:15

processes or things that develop over

39:17

time, someone with substantive trauma.

39:19

Uh, obviously lots of things going on here, but

39:21

there's also a lot of simple intraperitoneal fluid.

39:24

You know, what happened?

39:26

Well, the patient was, uh, went into nephrotic

39:28

syndrome, um, as a sequelae of what had happened.

39:31

And so it's simple water.

39:33

It is not indicative in this patient of bowel injury.

39:35

So what do you do with this?

39:36

Well, carefully look at the bowel

39:38

and mesentery for injuries.

39:39

Again, they can be subtle.

39:41

Uh, if you have other factors that are gonna,

39:43

you know, make you admit and observe the patient,

39:46

fine, uh, optimally, uh, you know, you're

39:50

gonna look at this, but you could potentially

39:52

repeat the CT with water-soluble oral contrast.

39:55

So again, we said, uh, initially in the, in the

39:57

trauma setting, we don't use oral, but if there

39:59

are specific concerns, uh, on the initial scan

40:03

or, or shortly thereafter for injury that we

40:06

didn't clearly characterize or appreciate, we can

40:09

repeat the CT with water-soluble oral contrast.

40:12

Um, and that can be a valuable maneuver.

40:14

So it doesn't require a laparotomy.

40:18

Um, let's talk about gas where it shouldn't be.

40:20

So again, the importance of

40:22

looking at lung and bone windows.

40:24

Um, things can change.

40:25

Uh, we've seen cases where.

40:27

Uh, on the initial portal venous phase,

40:30

there wasn't any extraluminal gas.

40:32

And then like five minutes later, 10 minutes

40:34

later, there was, and it was very subtle,

40:36

and this, things can change over time.

40:38

Um, some potential pitfalls here.

40:40

We don't generally do, uh, peritoneal lavage

40:43

anymore, but certainly that introduces fluid and air.

40:46

Uh, patients can have gas, air, uh,

40:48

spreading from other causes that aren't,

40:50

you know, directly related to bowel injury.

40:52

So barotrauma, mechanical ventilation, if

40:55

there's bladder rupture in the setting of a Foley

40:57

and air introduced, you can have air as well.

40:59

And then you have the concept of pseudo

41:00

pneumoperitoneum, which is extraperitoneal.

41:03

And we see this fairly commonly.

41:04

There have been a couple of papers

41:06

published in, uh, the, uh, trauma and

41:08

emergency imaging journals on this.

41:10

It's, uh, you typically see it in the anterior lower.

41:14

Chest and, uh, upper abdominal wall within

41:17

the layers of the, uh, muscle and fascia.

41:21

And if you look carefully, it,

41:22

it is not coming from bowel.

41:24

It is not coming from the peritoneal cavity,

41:27

but it can be due to substantive injuries,

41:28

more superiorly in the chest, or it can even be

41:30

from extraperitoneal injuries from the rectum.

41:33

And I'll show examples of that.

41:35

And then trickle.

41:35

It can occasionally truly coexist

41:38

with real pneumoperitoneum.

41:39

So if in doubt, delayed images, if you can, then, you

41:42

may not be able to do this, but decubitus positioning,

41:45

uh, careful assessment in multiple planes.

41:48

So here's an example of that.

41:49

And you can see obviously there's substantive,

41:51

uh, uh, gas here in various locations.

41:54

It's in, uh, fascia in the musculature deep.

41:57

It's in the retroperitoneum, but

41:59

it is not in the peritoneal cavity.

42:01

And in this case, it's due to a

42:03

substantive injury where we have, uh,

42:05

disruption of the coccyx, lower sacrum.

42:07

There was a rectal injury causing this.

42:10

Let's spend a little bit of time on pancreatic trauma.

42:13

This is a, uh, uncommon site of injury,

42:16

but it is a very important site of

42:18

injury and it's a potential, uh, miss.

42:22

And misinterpretation.

42:23

You can have secondary pancreatitis.

42:26

There's substantial mortality.

42:28

You can have complications developing

42:29

such as sepsis and fistulas.

42:32

Um, every once in a while you may actually

42:34

be able to see the discontinuity of the duct.

42:37

Um, and we're looking for the integrity or

42:39

lack of integrity of the main pancreatic duct.

42:42

Uh, Dave Drazen, who's at Maryland Shock Trauma,

42:45

um, I think it was at, at University of Miami at

42:48

the time, showed that if you have more than 50% of

42:52

the transverse diameter of the pancreatic parenchyma

42:55

disrupted, then the odds that you're gonna have

42:57

a main pancreatic duct injury are pretty high.

43:00

And it makes sense just in terms

43:02

of the geography and anatomy.

43:04

And so there are a variety of things to do.

43:06

If you know or suspect there's a

43:08

pancreatic injury, you can do MRCP.

43:10

It is, of course, non-invasive.

43:13

You can do it multiple times.

43:14

It has substantial value in the setting.

43:17

Not so much in the.

43:18

Hyperacute trauma setting, but for follow-up.

43:20

And then, of course, you can do ERCP, which would

43:23

be both diagnostic and potentially therapeutic.

43:27

And again, going back to our concept of packages,

43:29

this is a 64-year-old woman with a motor vehicle collision.

43:33

There is injury to the pancreatic

43:35

tail with associated edema, hematoma,

43:37

contusion, and there is an associated.

43:39

Uh, splenic laceration.

43:41

This was managed, uh, conservatively, successfully.

43:44

So what's the role for a subsequent MR?

43:47

Well, again, if there's a concern on the initial

43:50

CT, it eliminates additional radiation exposure.

43:53

Someone with pancreatic injury is likely gonna

43:55

have multiple scans over time if it's substantive.

43:58

And then it's a great way to non-invasively

44:00

assess the pancreatic ductal system, especially

44:03

in young, in young people, et cetera,

44:05

who we wanna reduce radiation exposure.

44:08

And this is similar to the concept of

44:09

just using MR, MRCP for follow-up in

44:12

pancreatitis related to other etiologies.

44:15

So here's someone with substantive injury.

44:17

We see a lot of peri, uh, pancreatic hematoma.

44:20

If you look, there is evidence of

44:21

contusion in, uh, traversing the, the

44:24

pancreatic, uh, neck and proximal body.

44:28

So there would be, and you can see it

44:30

in both the coronal and the axial plane.

44:31

So there should be high suspicion

44:33

for main pancreatic duct injury.

44:36

These representative, uh, images very, very

44:38

nicely demonstrate, um, this discontinuity.

44:41

And here you can see the abrupt

44:42

cutoff of the main pancreatic duct.

44:45

You can see the full-thickness, uh, area of

44:49

laceration/necrosis, lack of perfusion

44:52

here, um, uh, and again, very well demonstrated

44:55

on multiple planes, multiple sequences.

44:59

In contrast, this case, there's certainly substantive

45:02

things going on here, but it doesn't look like a

45:05

through-and-through, uh, injury to the pancreatic

45:07

neck, and the MRCP sequence showing the duct is intact.

45:12

So again, further supporting that initial observation.

45:17

Similar to the spleen.

45:18

We can have, and we can have this in

45:20

the liver as well, there can be, you

45:21

know, clefts running through things.

45:23

They usually have fat, there are variants of

45:26

anatomy, which can be confused with injury.

45:28

And we can have fat replacement in portions

45:31

through all the pancreas for a variety of reasons.

45:33

And again, we can problem solve delayed

45:35

images, uh, repeating the CT at 20, 40, 48

45:38

hours, using MR as a problem-solving technique.

45:42

Here's someone with a crush

45:43

injury at motor vehicle collision.

45:44

You can see there is a little bit of edema,

45:46

contusion in that anterior pararenal space.

45:49

It's not that impressive, but it's there.

45:52

And then on the CT, and this is a typical theme

45:56

done two days later, it's much more substantive.

45:58

There's trauma-related pancreatitis.

46:01

In this case, it was, uh, managed conservatively.

46:04

But this case, there are two different patients.

46:06

I think you'd have an almost

46:07

impossible time looking at these.

46:09

They look identical, telling what

46:12

is the injury and what is variant.

46:15

So, you know, place your bets.

46:16

Which one do you think is the injury?

46:18

50/50. I'll tell you.

46:19

One is an injury, one is a variant, and

46:21

in fact, the one on our right is the lack.

46:24

And you say, you know, how do you know that?

46:25

Well, I wouldn't know that if it wasn't

46:27

for the fact there was subsequent imaging

46:29

and here on the CT repeated two days later.

46:33

Now there's clearly evidence of

46:34

post-traumatic pancreatitis with fluid

46:37

and inflammation in the neighborhood.

46:38

So that makes it easy.

46:40

So tincture of short-term time

46:42

follow-up can be very important.

46:45

We could spend, uh, I don't

46:46

know, two hours on the diaphragm.

46:48

We'll just spend a couple of minutes as we

46:50

head towards the latter part of the lecture.

46:52

Um, the sensitivity of CT

46:54

traditionally is considered to be low.

46:57

The right diaphragm, which is, quote, generally

46:59

protected by the liver, uh, can be injured

47:02

somewhat less commonly, but it happens, and

47:04

that's very problematic to sort that out.

47:07

We can have pre-existent defects that can

47:09

simulate, uh, injury, and if we don't have prior

47:12

imaging, we usually don't to sort that out.

47:14

That can be problematic.

47:16

So important to, uh, remember to look at the diaphragm.

47:20

That may be the most important thing to remember in

47:22

both the blunt and the penetrating trauma scenario.

47:25

Look in multiple planes.

47:27

I can tell you as recently as a week and a half ago,

47:30

we had a quality assurance case presented in our

47:32

quarterly conference where there was a missed or delay

47:36

in diagnosis of a left diaphragmatic, uh, injury.

47:40

And we've seen several of them in the last few

47:41

years that it's not, again, that nobody's trying.

47:43

It's just that it's, it's tricky.

47:45

There are distractors, there are multiple things

47:47

going on, and, uh, people may forget to look for it.

47:51

Uh, there are a host of signs, we could do a whole

47:54

hour on just the CT signs, the stigmata for, uh,

47:58

the different forms of diaphragmatic injury

48:01

ranging from subtle to obvious, and they have

48:03

various names, the collar sign, the dependent

48:06

visceral sign, the dangling diaphragm sign.

48:08

I mean, people get kind of creative with these.

48:10

There's literally like 12 or 13 of them.

48:13

A lot of them originated, again, from

48:14

the University of Maryland group.

48:16

Certainly if you see direct discontinuity in a normal,

48:18

abnormal location of things, then it's obvious.

48:20

But, uh, often it's the, uh,

48:23

initial scan doesn't have those.

48:25

And, um, it's only when the patient comes in,

48:28

uh, or is imaged in that setting or comes in

48:31

hours, days, or occasionally decades later.

48:35

Do you recognize that?

48:36

So here's someone with a right diaphragmatic tear.

48:39

Um, wasn't really appreciated

48:41

prospectively in the blunt trauma setting.

48:43

And again, this is not, uh, an unusual scenario.

48:46

They come in literally years later, in

48:48

this case with a strangulated hernia.

48:51

Notice the

48:52

hardware from the prior trauma, which is a

48:54

big clue, and obviously a high-grade, uh,

48:57

uh, both small and large bowel obstruction

48:59

because the bowel is herniated, it's

49:01

strangulated, and it's very angry looking.

49:04

Let's finish up with a couple of slides, and then we'll

49:06

take some questions on, uh, major vascular injuries.

49:09

Thankfully, these are uncommon, uh, to rare.

49:12

They can be lethal.

49:13

Folks may not make it to the ER, to the trauma center,

49:17

to CT, and typically the mechanisms are, you know,

49:21

major things, decelerations, rapidly, high-velocity,

49:24

high-force injuries, direct crush injuries, et cetera.

49:28

And again, we see, um, in various organs,

49:31

uh, spectrum of findings, active extra, pseudo

49:34

aneurysms, dissections, flaps, thrombosis.

49:36

It really runs the gamut.

49:38

Uh, and these can, of course, occur in

49:40

various parts of the body, but we're

49:42

focusing here on the ab and pelvis.

49:43

So we already talked about active hemorrhage.

49:46

I won't spend too much time on this again at.

49:48

Uh, will, uh, you know, become bigger, less

49:51

well-defined, um, and doesn't follow the blood

49:55

pool on the delayed imaging, remains dense,

49:57

where pseudo aneurysms are usually well-defined.

50:00

They don't change in size in the different

50:02

phases, and they have a blood pool, uh,

50:06

attenuation on all, uh, acquisitions.

50:09

AV fistulas are tricky.

50:10

Uh, we don't see them very commonly at all, uh, but

50:13

as I showed, you may see that early draining vein.

50:16

Um, and there may be, uh, frequently

50:19

adjacent hematoma or other injuries.

50:21

So here's a case from Mike Patlas.

50:22

Kind of a crazy case.

50:23

And if you do enough trauma imaging in a busy trauma

50:26

center, you're eventually gonna see the weird things.

50:28

This ended up being an accessory upper pole

50:31

renal artery, as you can see in the cor images.

50:34

And this, uh, in the trauma

50:36

setting formed a pseudo aneurysm.

50:38

And, you know, sometimes things

50:40

occur in, in, in con confluence.

50:42

It isn't always one or the other.

50:44

So there's actually a pseudo aneurysm, but it's

50:46

not completely confined, and it's actually bleeding.

50:49

So it's both a pseudo aneurysm and active arterial

50:52

extravasation going into the right retroperitoneum.

50:55

And that was not initially appreciated as

50:58

to, you know, there was a pseudo aneurysm

51:00

there underlying the blood and the bleeding.

51:03

Here's a case from Jorge Soto, and you may notice

51:05

this was typical sort of mechanism here, is someone

51:08

thrown off a motorcycle, someone standing on

51:10

the street and a truck hits them on their flank.

51:13

You know, there's a major degloving type injury.

51:16

Look at the asymmetry.

51:17

This left, uh, mid-abdominal musculature

51:21

just, just been completely sheared apart.

51:23

There's an acute hemorrhage, uh, acute, uh, injury.

51:26

There's hemorrhage, and the more subtle thing

51:29

is that there's peri-aortic blood and

51:32

injury to the aorta, and there's actually

51:33

a short segment dissection flap there.

51:36

So occasionally you have actual sort of shearing

51:39

of the, of the vessel, and this is an uncommon

51:41

place, certainly, uh, for that kind of injury.

51:43

Again, this could be also seen in

51:45

the setting of a Chance fracture.

51:46

As I mentioned earlier, here's the conventional

51:48

angiogram showing that corresponding, uh, finding.

51:52

Uh, and then really weird things.

51:54

This is someone with a left renal venous disruption.

51:58

There's a venous pseudo aneurysm

52:01

here with surrounding hematoma.

52:04

Um, and that's again, an extremely unusual injury.

52:07

So in the last, uh, you know, 50 minutes,

52:10

uh, plus or so, we've gone over, uh.

52:13

Some pitfalls and pearls for approaching a CT of the

52:18

abdomen, pelvis, in primarily the blunt trauma setting.

52:21

I've tried to give you some tips in terms

52:24

of analysis, in terms of how to handle these.

52:27

Remember to reuse the AST

52:28

system for reporting injuries.

52:30

Again, you look 'em up easily.

52:31

There are other systems, but

52:33

that's the one that generally.

52:34

Uh, is used in most, uh, facilities including ours.

52:38

And there's, again, expectation to do that.

52:41

Uh, you'll get cited if, uh, you know, you get

52:43

audited and you're a level one trauma center.

52:45

I think it's every three years in the US, they come in

52:47

and they audit you, and they'll say to the, the trauma

52:50

team, okay, give me a hundred CT reports of various body

52:53

parts in the trauma setting, and they'll say, okay.

52:56

You know, 20% of them didn't

52:58

have AST grading or equivalent.

53:00

That's a, that's a, a deficiency.

53:02

Okay.

53:03

Um, we've gone over a technique, uh, again, in an

53:06

ideal world, you're gonna look at these real-time,

53:09

and you're gonna be in the CT scanner room, and

53:11

you're gonna watch the images come up, and you're

53:13

gonna protocol this prospectively, and you're gonna

53:15

get detailed information about what happened.

53:17

That's not the real world, right.

53:18

We're all aware of that.

53:19

Even in a busy trauma center, it's not

53:21

always gonna happen or often gonna happen.

53:23

So you have to do your best with here.

53:25

We do definitely want, in the significant blunt

53:28

trauma setting, to do both the late arterial

53:31

phase and the portal venous phase imaging of the

53:35

upper mid abdomen, and often we'll extend that to

53:37

a full and pelvis, depending upon the mechanism.

53:40

We always wanna look at our multiplanar

53:41

reformats, and then when we're doing.

53:44

Our, you know, secondary search.

53:46

We've already, you know, discussed the major

53:48

things that are potentially life-threatening

53:50

with the surgical team, trauma team then,

53:52

and we're gonna do our official reporting.

53:55

Um, we're gonna look at the areas we know we

53:57

can miss, the mesentery, the bowel, the pancreas,

54:00

the diaphragm, and look for subtle injuries.

54:03

And then make recommendations.

54:04

You can again communicate a second time,

54:06

Hey, I'm working on the official read now.

54:09

And there was a, a, I think there's a subtle injury to

54:11

the diaphragm, you know, that sort of communication.

54:14

Um, and, and so, uh, the other thing I should

54:17

say is, you know, here's another scenario.

54:19

What if there are several traumas?

54:21

You know, there may be one motor vehicle collision,

54:24

but it's, you know, several victims at once and

54:26

you're really overwhelmed with having to assess it.

54:29

What I would recommend you do is to do that, you

54:32

know, quick search, wherever you like to do at all.

54:34

Just look at all three or four of those

54:36

and just quickly identify the things

54:38

that are gonna kill somebody, and then.

54:40

Start your dictation once you've said,

54:42

okay, trauma team, patient A has nothing,

54:45

patient B has a, a, a, you know, grade

54:47

two liver injury, patient C is this.

54:50

You've communicated it and say, listen,

54:52

I'm working on the official reports.

54:53

There's several trauma patients at once.

54:55

I'll get back to you if I see something else.

54:57

Um, the need for short-term interval follow-up if

54:59

necessary for the bowel, for the urinary tract.

55:02

And then finally, I'll leave with this.

55:03

We did a, uh, online Radiographics exhibit.

55:07

Um, Mike Patlas led that, it was published a few

55:09

years ago, and it's still, I think, available

55:11

on the Radiographics website, and it covers a lot

55:13

of material that I've, I've gone over here.

55:16

So, with that, we'll close, I think

55:17

we have a few minutes for questions.

55:18

I want to again thank, uh, Jan

55:20

Collins for the kind invitation.

55:21

It's really a pleasure and honor to do this.

55:23

My first time to present at MRI Online, it's

55:26

also sort of fun because I got a text, uh, two

55:29

days ago from one of my former trainees, Tu

55:31

Bordia, who actually gave Wednesday's lecture,

55:34

and I'm like, that's a great coincidence.

55:36

Great.

55:36

It's great when people you train,

55:38

you know, the goal as a mentor is to,

55:40

you know, have people do what you're

55:42

doing, if not even better, you know, so.

55:44

Um, I was really pleased to see,

55:46

uh, you know, the company I was in.

55:48

This is a body imaging CT talk, but the

55:50

other two talks this week were on, um, neuro.

55:53

And so I hope you, uh, enjoyed this

55:55

and enjoyed those lectures as well.

55:57

And again, thank you for the honor of presenting.

55:59

It's great to actually do this live.

56:01

It's, uh, you know, a bit more challenging for those

56:03

who aren't used to speaking, but I, I find this much

56:06

more, uh, enjoyable to actually do this in front

56:09

of an audience, albeit not, you know, in person.

56:11

But I think it's really a great experience and I

56:13

hope you found this enjoyable and, and got a couple

56:15

of tips for how to handle, uh, imaging of the CT

56:19

scan of the ab pelvis in the blunt trauma setting.

56:24

Alright.

56:24

All right.

56:24

It does look like we have one question

56:26

in the Q and A feature right now.

56:28

Um, okay.

56:32

All right.

56:33

So there it is.

56:33

Okay.

56:34

Go.

56:34

Okay, so, uh, this is, can we use Omnipaque,

56:37

which is, you know, iodinated water-soluble

56:39

contrast, as oral contrast for acute

56:42

abdominal blunt trauma for intestinal injury.

56:44

So the answer is, of course,

56:45

we can, it's a great question.

56:48

Uh, but it's not so much the issue of, you know.

56:52

Extravasation of contrast into the peritoneal cavity.

56:55

I honestly haven't read it, but I'm aware of a

56:58

reference from some very, uh, veteran, uh, abdominal

57:01

radiologist published this year in the AJR revisiting

57:05

the issue of, you know, what is the problem with,

57:08

uh, you know, potential extravasation of a barium

57:11

based contrast media into the peritoneal cavity.

57:15

And my take on this has been severely overrated.

57:18

I mean, I, I have never seen

57:19

barium peritonitis in my career.

57:21

I've been doing this, uh, if you go back to

57:23

my, you know, days of dabbling as a medical

57:26

student, it's, it's, it's, you know, pushing

57:28

30, I don't know, 35, 37 years at this point.

57:31

I think it's completely overrated

57:33

and, and a, and a myth, basically.

57:35

So it's not so much the concern that you

57:37

might actually lead to extravasation if

57:39

you use the typical and barium-based

57:42

oral contrast. The issue is time.

57:45

That's the problem.

57:46

The problem is the golden hour.

57:47

You know, surgeons, particularly trauma surgeons,

57:50

you know, they want the answer yesterday.

57:52

So it's not so much the risk of giving

57:55

it, it's the delay in giving it.

57:56

Now, you know, do you want to throw

57:58

in an NG tube and give everybody, you

58:00

know, contrast quickly in this setting?

58:02

The yield is so small because the incidence

58:05

of, you know, distal gastric duodenal injury,

58:10

it happens, but it's really very, very unusual.

58:13

And so the yield is really not

58:16

such that it justifies doing that.

58:18

So the, the approach, and that again,

58:20

this is in blunt trauma, right?

58:21

In penetrating trauma, there are other

58:23

controversies. People, and we've done some work,

58:25

we presented RSNA, others, there've been

58:27

some recent, Mike Patlas actually published,

58:29

I think last year, earlier this year,

58:32

in the AJR, a meta-analysis looking at

58:34

the whole issue of triple contrast, oral,

58:38

rectal, and intravenous, is that necessary

58:41

in the penetrating trauma setting.

58:42

So it's a different situation here, but in

58:45

general, the yield really isn't justifiable.

58:47

What I would again recommend is if there's a

58:49

concern on the initial, uh, review, then you

58:52

can certainly do that if the patient's still on

58:55

the CT table, and more realistically bring them

58:57

back in the short term and repeat the CT through

59:00

the area of interest with water-soluble, you

59:03

know, contrast through typically an NG tube.

59:05

So it's a great question.

59:07

Um, and, and that's sort of my take on, on what

59:09

we would do and what, uh, the literature does

59:12

generally in the setting of, uh, penetrating trauma.

59:15

Uh, we do what the surgeons want.

59:17

So even though we may not think the yield is

59:19

particularly high, and there's literature now

59:21

supporting that from giving rectal contrast, and

59:23

it can be, you know, unpleasant for everybody,

59:25

uh, we'll do it if they really insist on it.

59:30

Well, that seems to look like

59:31

it's it for the questions.

59:33

Um, so as we bring this to a close, I wanna

59:35

thank Dr. Katz for this lecture today.

59:37

And thanks to all of you for

59:39

participating in our noon conference.

59:41

A reminder that this conference will be available

59:43

on demand on MRIonline.com, and in addition to

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all previous noon conferences, uh, be sure to

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join us again on Monday for a lecture from Dr.

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Amar Shah on imaging of left ventricle assist devices.

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You can register for that at MRIonline.com and follow

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us on social media at the MRIonline for updates

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and reminders on the upcoming noon conferences.

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Thanks again and have a great day.