Interactive Transcript
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Hello, and welcome to Noon
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Conference hosted by MRI Online.
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In response to the changes happening around
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the world right now and the shutting down of
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in-person events, we have decided to provide free
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Noon Conferences to all radiologists worldwide.
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Today, we are joined by Dr. Douglas Katz.
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Dr. Katz is the Vice Chair of Research at NYU
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Langone Hospital in Long Island and Professor of
0:27
Radiology at the Long Island School of Medicine.
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He has extensive experience in academic radiology.
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A reminder that there will be a Q and A session
0:36
at the end of the lecture, so please use the
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Q and A feature to ask your questions, and we
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will get to as many as we can before time is up.
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That being said, thank you all
0:44
for joining us today, Dr. Katz.
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I will let you take it from here.
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So, it's really a pleasure and honor to do this,
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and it's actually nice to actually, although not in
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person, in person, do something live for a change.
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So, that's really appreciated.
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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
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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.
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