0:02

Hello and welcome to Noon

0:03

Conference hosted by MRI Online.

0:06

In response to the changes happening around

0:08

the world right now and the shutting down of

0:09

in-person events, we have decided to provide free

0:13

Noon Conferences to all radiologists worldwide.

0:16

Today we are joined by Dr. Rony Kampalath.

0:19

Dr. Kampalath is an abdominal imager at the University

0:22

of California, Irvine Medical Center where

0:25

he has worked for two and a half years.

0:28

His professional interests include

0:29

oncologic imaging, as well as

0:32

resident and medical student education.

0:35

A reminder that there will be a Q and A

0:37

session at the end of the lecture.

0:38

So please use the Q and A feature to ask

0:40

your question and questions, and we will get

0:43

to as many as we can before our time is up.

0:45

That being said, thank you all

0:47

for joining us today. Dr. Kampalath,

0:49

I will let you take it from here.

0:52

Okay, great.

0:53

Um, I'm Dr. Rony Kampalath. I'm an Associate Professor at

0:57

the University of California, Irvine.

0:59

Today we're gonna talk about,

1:00

uh, abdominal and pelvic trauma.

1:03

Um.

1:04

So the way I structured this talk, um,

1:06

I'm gonna mainly gonna talk about CT in,

1:09

uh, trauma of the abdomen and pelvis.

1:11

Uh, I'm gonna start out by talking with

1:13

blunt abdominal trauma, which is what

1:15

most of what we see at, uh, UC Irvine.

1:17

Uh, and talk a bit about solid organ injury,

1:20

uh, bowel injury, and then patterns of injury.

1:22

And then I'm gonna finish up with

1:24

a bit about penetrating trauma.

1:27

Um, so a little bit, uh, about CT for trauma.

1:30

CT, um, as you may or may not know, is really

1:32

our workhorse for the evaluation of patients

1:34

with, um, uh, abdominal pelvic trauma.

1:37

Uh, and that's because it's

1:39

a really good study, right?

1:40

It has a very high negative predictive

1:42

value for, uh, significant injury.

1:44

Um, it's, uh, very useful to rule out

1:47

significant injury, uh, in the ER setting.

1:50

Uh, the clinical examination is very unreliable

1:52

because patients are frequently intoxicated,

1:55

have distracting injury, which, uh, prevents

1:57

a good physical or clinical examination.

2:00

Um, historically speaking, uh, penetrating

2:03

trauma has been treated surgically with

2:05

surgical exploration for all patients.

2:07

Uh, but increasingly now over the past few decades,

2:10

um, penetrating trauma has also been evaluated

2:13

initially with, uh, CT of the abdomen and pelvis.

2:17

At our institution, our, uh, protocol is just

2:20

to do a, uh, venous phase examination about 70

2:22

seconds after the, uh, administration of contrast.

2:25

That's not universal.

2:27

Uh, a lot of, uh, institutions will also do an

2:30

arterial phase examination at 25 to 30 seconds,

2:33

um, especially if there's a, um, high energy

2:36

mechanism of injury, uh, with, uh, displaced

2:40

pelvic fractures to look for a vascular injury.

2:43

Uh, some people have also, or some

2:44

authors have also advocated for the use

2:46

of a delayed phase three to five minutes after the

2:48

administration of contrast, predominantly to evaluate

2:51

the, um, the, uh, bladder and collecting systems.

2:55

Uh, typically we do not use oral

2:56

contrast because it delays evaluation.

2:59

Uh, oral contrast can sometimes be

3:01

helpful to identify bowel injury.

3:03

Uh, but, uh, we don't use it

3:04

on the initial examination.

3:06

If there is concern for bowel injury, uh, you can do

3:09

a repeat examination with oral contrast afterwards.

3:13

Um, so this is a nice image that I took

3:15

from the website, uh, Radiology Assistant.

3:18

Um, and, uh, I like this image because it kind of

3:20

shows you this poor individual with sort of every

3:24

pattern of injury that you can see or that you

3:26

should look for on a CT of the abdomen pelvis, right?

3:29

Um, in terms of solid organ injury, uh, you can

3:32

look for contusions, which is just sort of a

3:35

ill-defined area of low attenuation within an organ.

3:38

Lacerations tend to present as, uh, branching or

3:42

linear hypoattenuating structures within an organ.

3:45

Uh, intraparenchymal hemorrhage, uh, hemoperitoneum,

3:49

pneumoperitoneum are all things you should

3:51

be looking for as well as active bleeding.

3:53

Devascularization.

3:55

This kind of gives you an overview for the

3:56

things you should be, uh, keeping an eye

3:58

out for when you evaluate a CT after trauma.

4:03

Uh, one thing I want, uh, everyone to understand

4:06

about, uh, trauma is over the past few decades, uh,

4:09

there has really been a trend towards non-operative

4:11

management, uh, in blunt abdominal trauma.

4:14

And this has been facilitated by the use of CT.

4:17

Um, and because of that, today about 80%

4:19

of liver injuries, 50% of splenic injuries,

4:22

and almost all renal injuries are managed,

4:24

uh, conservatively or non-operatively.

4:28

So let's start with, uh, splenic injury.

4:30

Uh, the spleen is the most commonly injured organ.

4:34

Um, most, uh, splenic injury

4:36

can be managed non-operatively.

4:40

So let's start with a case.

4:43

Let me move this.

4:46

So this is a, uh, 26-year-old, uh, male who

4:49

fell off a horse, um, uh, and came into our

4:52

ER, uh, for a blunt abdominal trauma obviously.

4:55

So I'll give you a second to look at this.

4:57

What are the pertinent observations, things you

4:59

have to include in your, uh, radiology report?

5:01

I.

5:05

So obviously here in the spleen, in the

5:07

left upper quadrant, there's a, a, a

5:09

linear hypoattenuating area in the spleen,

5:11

which, uh, look looks like a laceration.

5:14

Um, and also, uh, there's this right along

5:18

the, uh, along the, um, uh, periphery of the

5:21

spleen, there's, uh, free intraperitoneal

5:23

fluid and it's hyperdense fluid.

5:24

So there's a, a small to moderate hemoperitoneum here.

5:29

So here you would say, um, there's a splenic

5:31

laceration, uh, as well as a hemoperitoneum.

5:35

Um, right.

5:36

So we'll keep that in mind as we go to our next case.

5:42

So this is a patient, she's a 36-year-old

5:44

lady who was in a, uh, motor vehicle accident.

5:46

She also has a splenic injury.

5:48

I'll give you a second to look at the images, um, and

5:51

to figure out what the pertinent observations are.

5:56

So, like we said, um, the, um, uh, the abnormal

6:00

area, the area of injury is the spleen, right?

6:04

Um, so this looks a bit different

6:08

from the prior examination.

6:10

So what is the finding?

6:13

How does it affect management?

6:15

So I wanna, what I wanna draw your attention

6:17

to is, like on the previous examination,

6:19

there's this hypoattenuating area.

6:21

In the spleen, there's a small hemoperitoneum,

6:24

but also something that was on, that's on this

6:26

exam, which wasn't on the prior examination, was

6:28

the presence of active contrast extravasation.

6:31

So, active contrast extravasation is gonna be an

6:33

area of, uh, contrast blush within the, uh, splenic

6:37

parenchyma that's almost as bright as the blood pool.

6:39

Uh, so this is an, uh, this is evidence of

6:42

um, active, um, intraparenchymal hemorrhage,

6:44

and this, um, uh, predicts a high failure

6:47

rate for non-operative management.

6:49

So these patients often need some sort of

6:51

intervention, whether it's, um, um, embolization

6:55

or, um, laparotomy, uh, for management.

6:58

And so it's very important when you

6:59

describe splenic, um, injury, not only to

7:02

mention the, um, type of injury, but the

7:05

presence or absence of active extravasation.

7:09

Here is, um, the, um, AAST Splenic Injury

7:13

Scale, which you may be familiar with.

7:16

Uh, this is the most recent, uh, revision in 2018.

7:20

Um, and that's important because the most

7:23

recent revision, uh, mentions splenic, uh,

7:26

um, active extravasation in the spleen.

7:28

So for example, here in grade four, any injury, um,

7:32

in the presence of splenic vascular injury or active

7:34

bleeding, confined within the splenic capsule is

7:36

considered a grade four, uh, grade four injury.

7:39

So previous, um, uh, editions of the AAST, uh,

7:43

Splenic Injury Scale did not include a reference

7:46

to active bleeding, and as such, they weren't,

7:48

they were criticized for not being very good

7:50

at, at predicting the need for, um, surgery.

7:56

Um, so, so make sure if you're using the A

7:58

AST, uh, scale to grade your injury, uh, to

8:00

make sure that you use the most recent, uh,

8:02

revision, 'cause it does include reference to a

8:05

splenic vascular injury with active bleeding.

8:07

Note that active bleeding, confined within the

8:09

splenic capsule is a grade

8:12

four injury, whereas active bleeding beyond the

8:15

spleen into the peritoneum is a grade five injury.

8:18

So our take-home points are, um, most splenic

8:21

injury can be managed non-operatively.

8:24

Uh, and look out for active extravasation.

8:26

Make sure to comment, uh, on whether if there is

8:29

active extravasation, whether that extravasation

8:31

is confined within the splenic parenchyma, or

8:34

whether there's bleeding into the peritoneum.

8:38

Okay, moving onward to liver injury.

8:40

Um, the liver is the, actually the second

8:42

most commonly injured organ after the spleen,

8:44

but it has a higher mortality than splenic

8:46

injury and is in fact the most common cause

8:48

of death after, uh, blunt abdominal trauma.

8:51

The most frequently injured part of the

8:53

liver is the posterior right hepatic lobe.

8:57

So let me give you a case.

8:58

This is a patient who, um, was in a car accident.

9:06

So here's the, um, um, abnormal,

9:09

the abnormal area, right?

9:10

Um, and I'll give you a second to look at that.

9:12

Take a look at what the pertinent observations are.

9:21

So what do you see here?

9:22

You see in the right posterior hepatic lobe,

9:24

there's sort of this large ill-defined area of

9:27

hypoattenuation in the, uh, right hepatic lobe.

9:30

Probably going to be, um, an intraparenchymal

9:32

hematoma, a contusion and intraparenchymal hematoma.

9:35

The other important observations to make are, um.

9:40

So what are the, uh, important associated, uh,

9:42

observations here where the yellow arrow is?

9:44

You see a small focus of what looks like active

9:46

extravasation or a small pseudoaneurysm.

9:49

Uh, so that's important to mention in your report.

9:51

And then the other important finding is

9:53

that there's a hemoperitoneum, right?

9:56

Um, so these are things that you

9:57

have to include in your report.

9:59

Um.

10:05

So let's move on to the next case.

10:06

This is another patient who

10:07

was, um, in a, um, car accident.

10:11

This patient also has a, uh, hepatic hematoma, right?

10:14

There's a crescentic hematoma, uh,

10:17

along the periphery of the liver.

10:20

Um, and note how this hematoma is a bit

10:23

different from the one we saw in the prior case.

10:25

Um, liver hematomas after blunt

10:27

trauma come in two flavors, right?

10:29

There's the intraparenchymal hematoma, uh,

10:31

which, uh, looks like that last case where it's

10:33

intraparenchymal, it's ill-defined, whereas

10:36

subcapsular hematomas like this one look like,

10:39

uh, areas which cause mass effect on the liver

10:42

parenchyma.

10:43

In this case, there's probably both a

10:45

subcapsular and an intraparenchymal hematoma.

10:47

You can see, uh, here on the right, on the right

10:50

side, there's, uh, there's, uh, blood within the

10:54

liver parenchyma and along the, uh, liver capsule.

10:58

The other important finding to mention is

10:59

that there's active extravasation, and this

11:02

active extravasation, as opposed to the last

11:04

case, isn't confined to the liver parenchyma.

11:06

There's, in fact, bleeding into the

11:08

peritoneum with a, a small hemoperitoneum.

11:11

So these are all important findings to

11:12

mention, and this patient will likely require

11:14

some sort of, um, uh, intervention, either

11:17

in the IR suite or in the operating room.

11:22

This is the 2018 revision of

11:24

the AAST Liver Injury Scale.

11:26

Uh, this one also incorporates

11:28

vascular injury with active bleeding.

11:31

Um, so in grade three you'll see vascular injury

11:33

with active bleeding contained within the liver

11:35

parenchyma. Uh, grade four injury, uh,

11:38

includes vascular injury with active bleeding,

11:41

breaching the liver parenchyma into the

11:42

peritoneum like we saw in the most recent case.

11:48

Excuse me.

11:51

Right.

11:51

So liver injury, um, historically it's been

11:54

managed operatively, but with the help of CT,

11:56

we can, uh, risk stratify patients who can be

11:58

managed conservatively without a trip to the OR.

12:01

Uh, and patients will need more, uh, aggressive care.

12:05

Uh, delayed complications of,

12:07

uh, liver injury do occur.

12:09

And that's a nice segment to this next case.

12:11

So this case, uh.

12:13

Um, this, uh, in this case, this is a patient

12:16

who was in a, a motor vehicle collision, uh,

12:19

presented with abdominal pain, and we did a CT

12:21

one month after the, uh, motor vehicle collision.

12:26

Uh, so here's the area of interest, right?

12:28

There's a, um, uh, collection, uh,

12:31

and that's not the gallbladder.

12:32

You can see on the coronal image it's a

12:34

little too low, uh, to be the gallbladder.

12:37

Um, so what is this?

12:41

What's your differential

12:42

diagnosis for this collection?

12:44

And if you think you know what

12:45

it is, how do you prove it?

12:46

One month after an MVC, you have a peri-

12:48

hepatic collection. Note also on this

12:51

image there's, um, you know, there's

12:52

evidence of, uh, liver parenchymal injury.

12:55

I.

13:00

So this is, of course, a, uh, a biloma.

13:02

So bile leak is a not uncommon, uh,

13:05

delayed complication after liver injury.

13:07

Um, and then, uh, you can, uh, you

13:10

can prove that it's, if you've.

13:11

Fact that there's a biloma, you can prove it

13:13

by either doing a nuclear medicine hepatobiliary

13:16

scan, uh, so-called HIDA scan, or a, um, MRI of the

13:20

abdomen with hepatobiliary phase contrast or Eovist.

13:23

Um, and if you see, um, opacification

13:26

or, um, uh, of the, uh, collection, then

13:29

you know that it communicates with the

13:30

bile system and is in fact a biloma.

13:32

Uh, once you've identified a biloma, you're not done.

13:35

Uh, remember that bile can erode the

13:37

vessels and form a pseudoaneurysm.

13:39

And for that reason, there's a high correlation

13:41

between bile injuries and pseudoaneurysms.

13:44

So every time you see a biloma, make sure to

13:45

look carefully for evidence of vascular injury.

13:49

Um, other things on your, um, other sort of

13:51

presentations for delayed complication after liver

13:54

injury include, uh, biliary stricture, uh, vascular

13:58

complications like pseudoaneurysm like we mentioned.

14:01

And then abscesses.

14:02

Abscesses can look like bilomas,

14:04

but abscesses are less common.

14:08

Okay, great.

14:09

Moving away from the liver, this is

14:11

another patient who was in a motor vehicle.

14:13

Actually.

14:13

This patient was, uh, struck by a car.

14:15

This was a pedestrian struck by a car.

14:18

The, um, abnormality, I'll give

14:20

you a second to look at the images.

14:24

So here you see, um, a linear hypoattenuating,

14:27

uh, thing in the right kidney, and then there's

14:30

a small amount of, uh, perinephric fluid.

14:32

So this is a, uh, uh, renal laceration.

14:38

So my question to you is, what are the

14:40

important pertinent negatives to mention while

14:42

describing a renal laceration?

14:47

Um, so the important pertinent negatives

14:50

are size of the laceration, of course, and

14:52

then involvement of the collecting system.

14:55

Remember, the vast majority of renal

14:56

injuries can be managed non-operatively.

14:59

Um, um, the therapeutic interventions

15:04

like surgery or, um, IR intervention are

15:07

usually reserved for patients who have

15:09

vascular injury or, uh, injury which involves

15:11

the collecting system with or without urinoma.

15:16

Moving onward.

15:18

Here's a case of another type of renal injury.

15:20

You can see that, um, this differs

15:23

from the prior case, right?

15:24

Um, here we have the, uh, right kidney is injured.

15:28

You have a crescentic collection along the

15:30

periphery of the kidney, and it looks like

15:32

there's mass effect on the renal parenchyma.

15:34

And this is a typical appearance of a

15:35

subcapsular hematoma of the right kidney.

15:38

Um, one of the things I want to caution you, uh,

15:41

about and one of the pitfalls in evaluating for

15:44

subcapsular hematoma: just make sure that you

15:46

don't get tripped up by, um, motion artifact.

15:49

Motion artifact can look often very, um, very

15:53

deceptively similar to a subcapsular hematoma,

15:56

not only of the kidney, but of the liver as well.

15:58

Uh, one of the ways you can differentiate a true

16:01

subcapsular hematoma from just motion artifact

16:03

is look at all the other structures in the—

16:05

Structures in the abdomen.

16:06

If everything else seems to be moving, then

16:08

what you're dealing with is likely not a

16:10

subcapsular hematoma, but just motion artifact.

16:15

Okay, great.

16:16

Moving onward, take a look at this case.

16:18

This is another case of a, um, a car accident, and

16:21

the abnormality is here in the, uh, right kidney.

16:34

So my questions to you about this injury

16:37

are, um, is this a renal contusion?

16:41

And if it is not—if it is not a renal

16:44

contusion (I kind of gave away the answer there),

16:45

but if it is not a renal con—

16:46

uh, contusion, why or why not?

16:48

How do you—how can you distinguish

16:49

what this is from a contusion?

16:54

So like a contusion.

16:55

Um, this is a, um, um, hypoattenuating

17:00

area in the upper pole of the right kidney.

17:02

Uh, it is different from a contusion though, in

17:04

that it's very sharply demarcated and it's very,

17:07

wedge-shaped along the periphery of the kidney, right?

17:10

This isn't a contusion.

17:11

This is, in fact, a segmental infarction of the kidney.

17:13

This patient needed to be taken to the, um,

17:16

the IR suite, um, uh, for, um, intervention.

17:20

You can see they've, um, they've, um, the ca— the

17:23

catheter is in the renal artery, and there's abrupt

17:25

cutoff of the, uh, right upper pole segmental

17:28

artery, uh, consistent with an infarction.

17:34

Moving on to other, uh, renal injuries.

17:37

This is a patient with, uh,

17:38

who was also in a car accident.

17:40

Take a look at these images and, um,

17:42

try to, um, figure out what you think.

17:52

So here are the abnormalities

17:53

in the right kidney, right?

17:54

So you see this is a delayed phase image.

17:56

You have opacification of the calyces in the

17:58

collecting system, and you also have what

18:01

appears to be extravasation of urine, uh, at

18:03

the level of the right ureteropelvic junction.

18:06

Um, you have, uh, urine, it kind of, um, extravasates

18:09

into the, uh, right lateral conal space and into the

18:11

extraperitoneal, uh, spaces of the anterior abdomen.

18:14

So this is a ureteropelvic junction

18:16

injury, uh, due to blunt trauma.

18:19

Uh, so UPJ injuries can be caused by

18:21

both penetrating injury or blunt trauma,

18:24

uh, due to sudden, uh, deceleration.

18:26

Uh, if there is, um, uh, injury due to blunt

18:30

trauma, it's usually at the UPJ because of

18:33

sudden deceleration and tension on the renal

18:35

pedicle, uh, causing, um, causing rupture.

18:39

Um.

18:40

Uh, so you often see a urinoma.

18:42

Typically you don't see hematoma.

18:45

Uh, and these UPJ injuries can,

18:47

uh, can come in two flavors.

18:48

They can either be an avulsion or a laceration, um,

18:51

a laceration, uh, maybe like this case where you

18:54

see extravasation of urine, but you see, um, um.

18:58

Opacification of the more distal ureter, uh, whereas

19:01

complete avulsion, uh, the, uh, UPJ is completely

19:05

dissociated from the more distal ureter, and you

19:07

won't see any opacification of the more distal ureter.

19:12

Great.

19:13

Moving onward.

19:16

What do you think of this, uh, case?

19:18

This is a case after, uh,

19:19

blunt abdominal trauma again.

19:24

So here it's, uh, it's pretty clear, right?

19:26

You see a non-enhancement of the

19:28

left kidney corresponding to a, uh,

19:31

injury to the left vascular pedicle.

19:33

This patient had to be taken to the, uh,

19:35

um, uh, interventional radiology suite.

19:37

Um, these were the results.

19:39

You can see there's sort of this linear.

19:40

Filling defect in the left renal artery.

19:42

This was thought to represent a,

19:44

uh, left renal artery dissection.

19:46

You can see there's delayed

19:47

enhancement of the left kidney.

19:49

This patient ended up being stented for repair, so

19:53

vascular injuries to the, um, um, the renal pedicle

19:57

can come in, uh, a couple of different varieties.

20:00

Uh, you can see dissection like in this case.

20:02

You can also see pseudoaneurysms and

20:04

even AV fistulas after blunt trauma.

20:06

So keep an eye out for, uh,

20:07

those types of vascular injuries.

20:11

Uh, so in the most recent revision of

20:12

the AAST Renal Injury Scale, there's a

20:15

lot of emphasis given to vascular injury.

20:17

Um, so make sure to look for vascular

20:20

injury and then comment on whether it's

20:21

confined within the pararenal fascia.

20:24

Um, uh, whether there's vascular injury

20:27

to a segmental renal artery or vein, or

20:29

whether there's a segmental infarction.

20:31

Um, uh, like we saw in that, uh, last case.

20:35

Um.

20:36

Uh, mention whether there is associated active

20:39

bleeding, um, uh, if there is an infarction.

20:41

And then in the most severe, uh, renal

20:44

injuries, there'll be avulsions of the renal

20:45

hilum, devascularization, devascularization

20:48

of the entire kidney due to a hilar injury.

20:51

Uh, and that's, uh, similar to what

20:52

we saw in the most recent case.

20:56

Um, again, um, um, the therapeutic

20:59

interventions, either endovascular,

21:01

urologic, or surgical, are reserved for,

21:04

uh, disruptions of the collecting system.

21:06

Um, so if you do have a laceration of the

21:08

kidney, make sure to, uh, look for whether

21:11

it involves the collecting system, uh,

21:13

and whether there's urinary extravasation.

21:19

Okay, so renal injury isn't as common

21:21

as splenic or, uh, liver trauma.

21:23

It occurs in about three to 10% of abdominal trauma.

21:26

Um, 80, uh, 80 to 90% of renal injuries are actually

21:30

seen in blunt trauma as opposed to penetrating trauma.

21:33

Uh, one useful clinical sign is that hematuria is

21:36

often present in patients with renal trauma, so that

21:39

you should maintain a high index of suspicion if the

21:40

patient has, uh, hematuria on initial evaluation.

21:46

Again, CT has been very helpful.

21:48

It's facilitated a move towards

21:49

conservative management.

21:50

Um, about 98% of renal injuries

21:53

can be managed non-operatively now.

21:55

Um, so, um, if there is concern for delayed

21:59

for a collecting system injury, uh, you can

22:01

consider, uh, repeat, uh, scanning with delayed

22:04

images to evaluate for urinary extravasation.

22:09

Okay, moving onward.

22:11

So here's a, um, CT cystogram.

22:14

I'll take—give you a second

22:15

to, uh, look at the images.

22:20

And then this, um, this additional

22:22

image, which I'm showing you.

22:28

So what type of bladder injury

22:29

is this, and how is this managed?

22:33

So, um, so this is a case of—this,

22:36

like we said, this is a CT cystogram.

22:38

You can see there's an obvious

22:39

abnormality, uh, anterior to the bladder.

22:41

There's all this contrast extravasation

22:43

in the anterior space of Retzius, and there's

22:46

extravasation of contrast into the, uh,

22:48

soft tissues of the right inguinal region.

22:50

The reason I showed you this,

22:51

uh, more superior image is to establish that

22:54

there's no contrast leaking into the peritoneum.

22:57

Um, there's no—you don't see any

22:59

contrast outlining the bowel loops.

23:02

So, uh, this is an example of an

23:04

extraperitoneal bladder rupture.

23:07

Um, there's a sign associated with

23:09

this if you like radiologic eponyms.

23:11

Someone thought that

23:12

this contrast extravasation into the

23:13

space of Retzius looks like a molar tooth.

23:15

And so this is called the molar tooth sign.

23:18

Uh, remember that extraperitoneal bladder injuries

23:20

can be usually managed, uh, non-operatively,

23:23

whereas, uh, rupture of, um, the bladder into the

23:26

peritoneum usually requires, uh, surgical repair.

23:32

Um, the chance of bladder rupture—so bladder

23:35

rupture is highly associated with pelvic fractures.

23:37

It used to be thought that the, uh, fracture fragments

23:40

themselves stabbed the bladder and caused the

23:43

bladder injury, but that's not necessarily the case.

23:45

Um, and remember that you can't do the

23:48

cystogram at the same time as the initial CT,

23:50

because the findings will confound one another.

23:52

Um, so you have to do the CT cystogram at a later

23:55

point if there's high suspicion for bladder injury.

23:58

Um, the way we do it at our institution—we

24:00

drain the bladder via an indwelling Foley.

24:02

Uh, we give contrast solution: 50 ccs of IV

24:05

contrast material in normal saline, and then

24:08

we instill about 350 to 400 ccs of contrast.

24:10

And then we do a CT of the pelvis.

24:14

And this is, uh, you know, as you

24:16

may know, very good for bladder rupture.

24:18

It's got about 100%,

24:20

uh, uh, and 99% sensitivity and

24:22

specificity for extraperitoneal rupture.

24:25

Uh, and over 90% sensitivity and

24:27

specificity for intraperitoneal rupture.

24:32

Okay, moving onward.

24:34

This is another case.

24:35

This is a 22-year-old male

24:36

with blunt abdominal trauma.

24:38

This is kind of a tough case.

24:39

I'll give you a few minutes—or a few

24:40

seconds, rather—to, um, look for the findings.

24:48

If I told you that the patient had an

24:50

elevated lipase, um, see if that would

24:53

help you to determine the findings.

25:01

So here are the findings right here.

25:02

You see this kind of ill-defined area of

25:05

hypoattenuation between the pancreatic

25:07

parenchyma and the splenic vein.

25:09

That's a small amount of fluid.

25:10

You also see it on the sagittal view.

25:13

So this is a pancreatic injury.

25:15

Um, and you know, like you can see here, it

25:17

can be very subtle, the pancreatic injury.

25:19

So it's a relatively uncommon injury.

25:21

Uh, it's only got about a 1.1%

25:24

incidence in penetrating trauma, and

25:26

less than 1% incidence in blunt trauma.

25:31

Um, one helpful, uh, tip is that

25:35

pancreatic injury is rarely an isolated injury.

25:38

Um, so if you do see, um, a severe mechanism

25:41

of injury with lots of solid organ injuries,

25:43

uh, look carefully for pancreatic injury.

25:47

Most of the, um, um, most of the blunt injury to

25:51

the pancreas occurs in the, um, pancreatic body.

25:54

Uh, look for a rising amylase and lipase.

25:57

Um.

25:58

And look for peripancreatic inflammatory changes.

26:01

Um, and in this case, sometimes pancreatic injury—

26:04

the only sign will be a little bit of subtle

26:06

fluid between the splenic vein and pancreas.

26:08

Uh, maintain a high-end index of suspicion,

26:10

especially if there's a lipase, uh, that's elevated.

26:13

I. And pancreatic injury can present as,

26:17

uh, contusions, which are non-linear, hypo

26:20

attenuating areas, lacerations, which

26:22

are linear, hypoattenuating regions.

26:24

Uh, and then make sure to look for

26:26

integrity of the pancreatic duct.

26:27

It's very important, um, for the surgeons

26:30

to know whether the pancreatic duct is,

26:32

um, involved by the pancreatic injury.

26:35

This is the AAST Pancreatic Injury Scale.

26:38

Uh, one thing I wanna call your attention

26:40

to is if there is a laceration or

26:42

parenchymal injury to the pancreas.

26:44

Make sure to tell the surgeons where it is,

26:47

um, if it is proximal to the superior

26:49

mesenteric vein via, uh, or, uh, distal to the, uh,

26:53

superior mesenteric vein.

26:55

Um, so, uh, that can affect surgical management.

26:58

So grade one, pancreatic

26:59

injury is usually non-surgical.

27:01

Grade two is variable.

27:03

Grades three, four, and five are

27:04

typically surgically managed.

27:09

Okay, let's look at this case.

27:11

This is another patient, blunt abdominal trauma.

27:17

What is the name of this sign here?

27:27

So this is of course the dependent viscera sign.

27:29

I don't know if you've heard of this, but what

27:30

you can see here is all the abdominal viscera

27:33

are lying, uh, against the, uh, thoracic

27:36

wall, and there's no diaphragm in between

27:38

the, um, viscera and the abdominal wall.

27:41

Uh, this is a, uh—

27:42

specific, fairly specific

27:44

sign of diaphragmatic injury.

27:45

And if you look at the coronal, you can

27:47

see there's a diaphragmatic injury with

27:48

herniation of the intra-abdominal contents.

27:52

So in diaphragmatic injury, uh, in blunt trauma, it's

27:56

due to a sudden increase in intra-abdominal pressure.

27:58

Uh, you'll see a diaphragmatic discontinuity

28:01

with herniation of intra-abdominal

28:03

contents like we did in this, this case.

28:06

Um, as you might imagine, our sensitivity for

28:08

diaphragmatic injuries on the right side is lower,

28:11

because the liver has kind of a protective effect.

28:13

Um, we're better at finding diaphragmatic injuries

28:16

on the left than we are on the right.

28:20

Moving onward.

28:24

After blunt abdominal trauma, what is your

28:26

differential diagnosis for this finding?

28:31

So the finding of course, is, uh, pneumoperitoneum

28:34

right after blunt abdominal trauma.

28:35

What do you think this, uh, could represent and does

28:39

it change, uh, does it change your differential?

28:41

If I show you this image, which is

28:43

of the same patient at the same time?

28:47

So this is a case of pneumoperitoneum, and

28:48

usually when you see pneumoperitoneum after

28:51

blunt abdominal trauma, you think of, uh, bowel

28:53

injury and perforation with pneumoperitoneum.

28:56

That's not, uh, that may be true,

28:58

but it's not always the case.

28:59

And there's—you have to remember, there's

29:00

a differential for pneumoperitoneum.

29:02

Um, if the patient underwent a peritoneal

29:04

lavage or had traumatic Foley placement,

29:07

um, that can also cause pneumoperitoneum.

29:09

Uh, but a common reason that we see in our

29:11

patients is translocation from the thorax.

29:13

If the patient had extensive thoracic injuries

29:16

with a, uh, pneumothorax or pneumomediastinum,

29:19

that air can, uh, translocate into the

29:21

abdomen causing a pneumoperitoneum, which is

29:24

unrelated to the presence of bowel injury.

29:27

If there is concern for bowel injury, one

29:30

thing you can do is, uh, give the patient

29:31

oral contrast and then, uh, re-scan.

29:37

Okay, next case.

29:39

Uh, so this is a young patient, uh,

29:41

again after a blunt abdominal trauma.

29:43

Um, the patient had no solid organ

29:45

injury, no obvious bowel injury.

29:47

What he did have was, uh, this finding here,

29:50

uh, what I'm pointing to is a small amount

29:53

of, uh, free, free fluid in the pelvis.

29:58

So in the absence of other, um, you

30:00

know, abdo—intra-abdominal, uh, findings,

30:02

what do you think this finding means?

30:04

Uh, and is it pathologic?

30:09

Well, in the 1990s, a lot of studies

30:10

suggested that, uh, free fluid in the

30:12

pelvis indicated occult bowel injury.

30:15

Uh, we see free—especially in a male patient, right?

30:17

We see free fluid in, uh, in reproductive female

30:20

reproductive-age female patients all the time.

30:22

Uh, what's less clear is what—

30:24

or what was less clear is what to do with a small

30:27

amount of isolated free fluid in a male patient.

30:30

Um, so like I said, in the 1990s, it was thought

30:32

that this suggested occult bowel injury.

30:35

Um, as our CT technology improved, we started

30:37

seeing, uh, small amounts of incidental free

30:40

fluid in lots more patients who otherwise had—

30:42

no evidence of injury.

30:44

And so more recent studies have suggested that

30:46

a small amount of fluid is actually okay, even

30:48

in a male patient, especially because these

30:50

patients get a lot of hydration after trauma.

30:53

Uh, I like to, um, direct

30:55

my residents to this paper.

30:56

This was published in Radiology in 2010.

30:59

They looked retrospectively—patients

31:02

with blunt abdominal trauma—uh, trying

31:04

to answer the question of whether a small

31:07

amount of fluid in the pelvis was okay.

31:09

Um, and what they found is:

31:11

if there is a very small amount of simple free

31:14

fluid deep in the pelvis, which is to say, um,

31:17

below the third sacral vertebral body, and,

31:20

um, if the fluid is simple in attenuation,

31:22

meaning not hyperdense free fluid, then it's

31:25

likely not a sign of bowel or mesenteric injury,

31:28

and you can safely, um, ignore it basically.

31:33

So small bowel injury can be very tricky

31:35

to see on the initial abdominal pelvic CT.

31:38

Uh, the problem is that the specific

31:39

findings are very, uh, insensitive, and the

31:42

sensitive findings are very non-specific.

31:45

Um, so the sort of spectrum of findings includes

31:48

focal bowel wall thickening, which is sensitive,

31:50

but not specific; contrast extravasation, focal bowel

31:54

wall discontinuity are two signs that are, uh, very

31:57

specific but not sensitive.

31:59

And then you can also see mesentery

32:00

stranding or intraloop fluid.

32:02

Um, if you see, uh, mesentery stranding and,

32:05

uh, focal bowel wall thickening in combination,

32:08

that's strongly suggestive of a bowel injury.

32:10

So the combination of

32:12

those two findings can be very helpful.

32:15

Um, so bowel injury—about 5% of patients

32:18

with blunt abdominal trauma—the small bowel is

32:20

the most commonly injured, uh, followed by the

32:22

colon and then followed then by the stomach.

32:28

Here's a special type of, um, bowel injury.

32:31

Um.

32:33

I'll give you a second to look at it.

32:35

Here you see, uh, thickening of the duodenal wall.

32:39

Um, this ended up being a, um, an, uh,

32:41

intramural hematoma of the duodenum.

32:44

Um, so, um, duodenal injuries can, uh, either, um, uh—

32:48

uh, present as, uh, intramural hematomas or

32:51

lacerations with extravasation of contrast.

32:54

And for that reason, the surgeons asked us to do

32:56

this, um, fluoroscopic examination where you can

32:59

see there's, um, um, abnormality of the mucosa

33:02

in the second portion of the duodenum related

33:04

to a hematoma, but no extravasation of contrast.

33:06

So this was safely managed, uh, conservatively.

33:10

Um, make sure to keep an eye out for duodenal injury.

33:13

It's not very common, but if it is

33:15

present, it has a significant mortality.

33:17

Um, we're not, uh, that great

33:19

at identifying duodenal injury.

33:21

There was one study which showed, uh, um,

33:23

accuracy of 57% for duodenal injury, and like

33:26

we said, hematomas—intramural hematomas—

33:29

of the duodenum are treated conservatively.

33:31

Lacerations with extravasation of

33:33

contrast are treated with urgent surgery.

33:39

Um, yeah.

33:42

This case I just wanted to show and tell.

33:43

This is just an example of, um, intra-abdominal

33:46

aortic injury due to blunt trauma.

33:48

Here's a dissection roughly at the aortic hiatus.

33:51

Um, and I just wanted to, um, mention to you,

33:54

so if you do have injury to the aorta due to

33:57

blunt trauma, it's usually in the thorax, right?

34:00

Blunt injuries to the abdominal

34:01

IVC and aorta are uncommon.

34:04

There's a 20-to-1 ratio: thoracic

34:06

to abdominal injury after

34:07

blunt trauma.

34:08

Um, oftentimes—so, uh, while, uh, blunt

34:11

injuries to the IVC and aorta are uncommon,

34:14

retroperitoneal hemorrhage is actually quite common.

34:17

And often what you see is kind of this

34:18

whole mess in the retroperitoneum.

34:20

You've got hemorrhage, you've got stranding.

34:22

It's unclear what's bleeding

34:23

or where it's coming from.

34:25

Uh, and this is often the case, right?

34:27

You see a retroperitoneal hemorrhage,

34:29

it's not clear where it's coming from.

34:31

Um, and so the radiologist—

34:32

um, one advice that I give is to

34:34

focus on the location, the source,

34:36

and the stability of the bleeding.

34:38

Um, look for evidence of active extravasation,

34:41

like we probably have in this case.

34:42

Um, and then, um, look for, um, and then describe

34:46

in your report where the bleed is located.

34:49

Uh, if you've read any operative reports

34:51

with, uh, retroperitoneal injury, you'll

34:53

see that the surgeons will describe, uh, will

34:55

divide the retroperitoneum surgically into

34:57

three, um, sections.

34:59

Zone one is the central retroperitoneum,

35:01

uh, consisting mainly of the

35:03

aorta, celiac axis, and so forth.

35:05

Zone two is the lateral retroperitoneum,

35:08

the renal arteries, and um, uh, veins.

35:11

And zone three is the pelvic retroperitoneum.

35:16

Okay, so we've spent the past few minutes

35:17

discussing, um, uh, organ by organ, um, uh,

35:21

the various injuries in abdominal trauma.

35:24

This is where I want to give you, um, I want

35:26

to encourage you to take a more holistic

35:28

approach, um, uh, evaluate the CT in total, um,

35:32

because abdominal-pelvic, uh, blunt trauma

35:35

frequently, uh, gives you

35:37

specific patterns of injury.

35:39

So think about where the trauma or where the force

35:42

is coming from. If it's coming from the right, um,

35:44

anterior, you think about right hepatic lobe, right

35:47

kidney, right adrenal injuries, diaphragmatic

35:50

injuries, pancreatic head injuries, and so forth.

35:52

These are often associated.

35:54

So if you see one, keep an eye

35:55

out for the other injuries.

35:57

If the injury is coming, um, anteriorly,

36:00

think about injuries to the left hepatic lobe,

36:02

pancreatic body, aorta, transverse colon, and so forth.

36:07

If it's coming from the left, think about

36:09

spleen injury, left kidney injury, diaphragmatic

36:12

injury, and pancreatic tail injury.

36:14

If it's coming from the posterior side, left or right,

36:17

think about flank contusions, lower rib fractures,

36:20

transverse process fractures, and T and L spine fractures.

36:23

The reason I'm telling you this is

36:24

because, like I said, these injuries can

36:26

be commonly associated, and especially

36:28

retroperitoneal injuries can be very subtle.

36:30

So if you're not looking for them carefully

36:32

based on what the mechanism of injury is,

36:35

uh, you may miss them.

36:36

Uh, so remember the words of, uh, Wayne Gretzky, who

36:39

was once asked to, uh, describe why he was so great.

36:43

He said, I don't skate to where the puck is.

36:45

I skate to where the puck is going to be.

36:47

What does this mean for radiology?

36:49

Remember to be proactive, not reactive.

36:52

Think about the mechanism of disease and look

36:54

for the findings that you expect to be there.

36:57

For example, look at this Chance fracture.

36:59

So this is a flexion-distraction injury, um, at the

37:02

thoracolumbar junction involving the posterior elements.

37:05

Um, the fulcrum is anterior to the spine, so if you

37:08

just identify this Chance fracture, you haven't,

37:11

uh, finished your job, especially in pediatric

37:14

patients, because of the mechanism of injury.

37:16

This is highly associated with pancreas,

37:18

small bowel, and mesenteric injury,

37:20

which can be very subtle. So may,

37:22

uh, keep an eye out for these injuries.

37:25

So I'm running a bit short on time.

37:26

I'm gonna talk a little bit

37:27

about, uh, penetrating trauma.

37:29

Um, these have traditionally been

37:31

managed surgically, uh, but more and more

37:33

we're using, uh, CT for, um, evaluation

37:37

of patients who've been stabbed or shot.

37:39

Um, CT has—

37:40

excellent sensitivity for excluding surgically

37:42

important injury and is cost-effective.

37:45

Prevents a lot of people from

37:46

undergoing, uh, unnecessary laparotomy.

37:49

Um, blunt trauma versus penetrating trauma—

37:51

there's a few differences when you evaluate the CTs.

37:54

Uh, in blunt trauma like we described, um,

37:57

there's a combination of injuries which cluster

37:59

based on mechanism, whereas in penetrating

38:01

trauma, the injury is determined solely

38:03

by the path of the knife or the bullet.

38:05

Um, in penetrating trauma—or rather, in blunt trauma—

38:08

there are well-protected organs like the, uh, aorta or

38:11

the pancreas, uh, which are only rarely, uh, injured.

38:15

Whereas in penetrating trauma, the wound

38:17

trajectory is kind of indiscriminate.

38:19

There are more pancreatic, rectal, and IVC injuries

38:22

in penetrating trauma rather than blunt trauma.

38:26

Also keep an eye out for small diaphragmatic

38:28

injuries, uh, which can be quite subtle but

38:31

can be potentially catastrophic if missed.

38:33

Um, gunshot wounds, um, as you might imagine,

38:36

cause more severe injuries than, uh, stab wounds.

38:39

Uh, they cause internal wounds

38:41

in about 90, 90% of patients. Uh, one-half

38:43

to two-thirds of stable patients with gunshot

38:46

wounds, uh, will require surgical repair.

38:50

Um.

38:52

On the other hand, stab wounds—about 50 to

38:53

75% of them enter the peritoneum, and about 50

38:57

to 75% of those will require surgical repair.

39:00

Um, the one mantra I want you to internalize

39:02

when looking for, uh, penetrating

39:04

trauma is that trajectory is everything.

39:07

Uh, so figure out what the wound track is.

39:09

Your wound track is depicted by tissue, tissue

39:11

destruction. Clues to the wound track, um, uh, include

39:16

gas, hematoma, bone fragments, or bullet fragments.

39:20

Um, that can—

39:20

kind of help you figure out where the

39:22

knife or the bullet, uh, uh, passed.

39:26

Uh, entrance wounds are usually

39:28

smaller than exit wounds.

39:29

Uh, also bullets when they hit bone kind

39:32

of cause a snowstorm pattern, which, um,

39:35

increase conically as they, uh, move forward.

39:37

Uh, so that can help you, uh, determine

39:40

whether, uh, what the wound track is.

39:42

Um, sometimes finding the

39:44

wound track can be very tricky.

39:46

Stab wounds, especially in the paraspinous

39:48

muscles, can be very, uh, subtle.

39:50

Uh, sometimes foci of subcutaneous gas can be helpful.

39:53

Um, although the subcutaneous gas can migrate

39:56

along soft tissue planes and, uh, kind of mislead

39:59

you, uh, remember not to just draw a straight

40:02

line between the entry and the exit wound.

40:04

Uh, bullets can wobble and bounce off bones,

40:07

um, and then differences in the phase of

40:09

respiration between the time the patient was shot

40:12

and the time of the scan can cause, uh, sort of, uh,

40:15

ambiguity in what the, um, what the bullet track was.

40:18

Uh, remember, patients can, uh, have old bullet

40:21

fragments in their abdomen, so those can mislead you.

40:23

And then bullet fragments can sometimes hitch a

40:25

ride via the GI tract or the vessels and end up in,

40:29

uh, positions that they, uh, weren't originally.

40:34

So peritoneal violation is one of the

40:36

important questions you have to answer,

40:38

uh, after, uh, penetrating trauma.

40:40

Um, pneumoperitoneum is very specific for

40:43

peritoneal violation after, um, penetrating

40:45

trauma, but it's only seen in 35% of patients.

40:49

Um, a more, um, common finding is free fluid

40:53

after, uh, peritoneal violation, which is

40:55

actually seen in about 85% of patients.

41:00

Okay, this is a patient who was, uh, in his

41:02

hotel room, lying in his bed when he got shot.

41:05

Um, I've drawn arrows to where the entrance

41:07

wound is and where the exit wound is.

41:09

You can see an obvious, um, uh, kidney injury here.

41:13

Uh, if you look carefully, you

41:14

can see a defect in the diaphragm.

41:15

This patient had a focal diaphragmatic injury and,

41:18

um, that's clear because of the, uh, the wound tract.

41:21

Interestingly, the wound, uh, the, the trajectory

41:23

goes through the stomach, but we don't see

41:25

any perigastric fluid collections or wall

41:28

thickening. Um, uh, but this patient

41:31

actually did have, uh, through and through

41:33

full-thickness, uh, stomach injury.

41:35

So if you do see a trajectory through

41:37

a hollow viscus, uh, that's, uh, very,

41:40

very suggestive for hollow viscus injury.

41:44

You can say with a high degree of confidence

41:45

if there is a trajectory through bowel,

41:47

that the bowel is in fact injured.

41:49

Uh, sometimes if you see—if you get lucky

41:51

and see contrast extravasation, that's

41:53

very specific, but it's not often seen.

41:55

Indirect signs of hollow viscus injury include mural

41:59

thickening, mesenteric hematoma, or mesenteric fluid.

42:03

Um, uh, this is just a nice image I took

42:06

from this, uh, Radiology article in 2015.

42:08

They used a, um, uh, curved planar reformat to

42:12

figure out the exact trajectory of the bowel.

42:14

If you have a—or rather the bullet—if you

42:17

have access to this at your institution, you

42:18

can really figure out very nicely what the

42:21

trajectory is and what organs may be injured.

42:24

Colonic injury is a special type of, uh, bowel injury.

42:28

Um, if you have a trajectory through the

42:29

colon, uh, you should suggest colon injury.

42:32

Other findings that you may see are fecal collections,

42:35

or pericolonic stranding, and contrast extravasation.

42:38

Um, if you've given rectal contrast, I—

42:43

So penetrating pelvic injury

42:45

is kind of a special situation.

42:47

Um, and it's special because

42:49

the surgeons may miss them.

42:51

Uh, the injuries in the pelvis are

42:52

often extraperitoneal, and they're

42:54

difficult to surgically explore.

42:56

Um, so it's important if there is penetrating—

42:59

um, trauma through the pelvis to mention any pelvic

43:01

injuries. In particular, rectal and ureteral injuries

43:04

can be easily missed on, uh, surgical exploration.

43:07

So make sure to comment if these

43:09

structures, um, are, uh, along the, uh,

43:12

tract, uh, or the trajectory of injury.

43:17

Very good.

43:18

Uh, and so that's more or less all I have.

43:20

So in summary, remember there's been a

43:22

trend over the past few decades towards

43:24

non-operative management, both in blunt

43:26

and penetrating trauma in abdominal trauma.

43:28

Our real workhorse is CT, which is

43:31

used to rule out significant injury.

43:33

Uh, identify patients who require

43:34

surgical or IR management.

43:36

And then CT is increasingly used for penetrating

43:38

trauma to identify peritoneal violation and look

43:41

for patients who may need immediate surgery.

43:45

Uh, remember then blunt trauma, look for

43:47

combinations of injury which cluster based

43:49

on mechanism. Uh, in penetrating trauma,

43:52

on the other hand, trajectory is everything.

43:54

And in ambiguous cases, especially

43:56

if there's suspected bowel injury,

43:58

follow-up studies can be very helpful.

44:02

And that's all I have.

44:03

Thank you very much.

44:05

Alright.

44:05

It does look like we have a few questions

44:08

from the audience in the Q and A feature.

44:15

Yeah.

44:15

So how did you—how do you differentiate

44:17

active extravasation from pseudoaneurysm?

44:19

That can be very difficult, and sometimes, you

44:22

know, at our, uh, institution, we just do a 72-second

44:25

portal venous phase, so we end up dictating,

44:28

um, pseudoaneurysm versus active extravasation.

44:31

If you're at an institution where

44:32

they do delayed phase images,

44:34

uh, a pseudoaneurysm would—expect you'd expect a

44:37

pseudoaneurysm to remain a small round ball of, um,

44:40

um, increased attenuation, whereas extravasation would

44:44

be expected to sort of diffuse into the parenchyma and

44:47

become less well-defined on more delayed, uh, images.

44:51

Um, okay.

44:53

Very good.

44:54

So the two questions on why we use, uh, portal

44:57

venous phase, uh, or venous phase is enough.

44:59

Yeah, that's a good question.

45:01

Like I said, a lot of, um, authors do

45:03

advocate, um, arterial phase images or delayed

45:06

phase images in our, uh, in polytrauma.

45:08

Uh, our experience has been that, um—

45:13

uh, that, um, uh, most of our studies are negative,

45:17

uh, and, um, most of our patients are young.

45:20

Uh, we're trying to balance the, um, uh,

45:23

the need to reduce radiation dose, uh,

45:25

and catch as many injuries as possible.

45:27

Um, we found that, um, um, for the—for

45:31

our patients as a whole, venous phase

45:33

images are, um, what we've gone with.

45:38

Uh, would you see a small intraparenchymal

45:42

pseudoaneurysm in liver on portal venous phase?

45:45

Yeah, you can certainly see it.

45:47

The images that I showed you were, um, uh, the

45:50

image I showed you was a small pseudoaneurysm,

45:52

and we did see it on portal venous phase.

45:54

I take your point that, um, it may be more visible

45:57

on arterial phase, but again, we, uh, uh, we've found

46:01

that we can see enough of them on portal venous phase.

46:03

Um.

46:06

Um, okay.

46:08

What is your intake on whole-body CT?

46:10

Uh, I'm not sure I understand that question.

46:12

Uh, is the question how many CTs we get?

46:19

We can, um, we can move to the next question.

46:22

Um, in AAST, do the gradings need to

46:24

meet all the sub-bullets or at least one?

46:26

It's just one. Uh, it doesn't need to meet all

46:28

the sub-bullets to make a particular grade.

46:32

Uh, can—do you use dual

46:34

energy for virtual enhancement?

46:36

That's a good question, which, um, we are, um,

46:39

uh, we haven't been using dual energy so far.

46:43

Um, I, uh, think some people do use virtual

46:45

enhancement, but I can't, uh, answer that question.

46:50

Uh, my thought about whole-body CT

46:52

and its indications. So people use the

46:54

term whole-body CT, um, differently.

46:57

Um, I think that you mean by

46:58

whole-body, head to—head to pelvis?

47:02

Is that—is that true?

47:04

Um, so I think that, um—

47:09

I think that CT, um, you know, when we, uh, when

47:13

we read cases in the ER, a lot of our studies are

47:16

negative and, um, I don't think that's a bad thing.

47:19

I think it's a good thing.

47:20

Uh, I think that CT has been shown to be

47:22

cost-effective in pre, uh, preventing,

47:25

um, um, unnecessary laparotomies.

47:28

And although I'm not a neuroradiologist.

47:30

Um, I'm sure the, um, the—it would be—you see

47:33

something similar with head and neck injuries.

47:35

Um, so, uh, I think, uh, CT is very

47:39

sensitive for, uh, important injuries.

47:42

I think, uh, you—I think it's generally

47:44

shown to be a good thing to have a low threshold

47:46

to, uh, to do a whole-body CT, especially if

47:49

the, uh, mechanism of injury, uh, supports it.

47:55

Okay.

47:55

What protocol do you use for

47:56

trauma scan with contrast?

47:58

So, uh, like I said, we do use, um, so, um.

48:03

Uh, let me think.

48:04

So we use, uh—so our abdominal pelvic

48:07

CTs are done in the portal venous phase

48:09

with, um, about a, um, 60 to 72-second delay.

48:12

Um, the lungs are actually scanned first,

48:16

so we do an earlier phase for the—for the chest.

48:19

Um, that's, uh, going to be, um, more of like

48:21

a, um, CTA protocol that we use for our chest.

48:28

Uh, in a patient with BA or history of allergy,

48:32

is it all right to administer contrast in?

48:36

Um, I think, uh, you know, I think it is.

48:40

I think that, um, uh.

48:44

Well, you know, you have to really

48:46

weigh the risks and, and the benefits.

48:48

Uh, certainly in severe mechanism of trauma,

48:52

I think it's, uh, totally okay to administer

48:55

a contrast and then, uh, deal with any

48:57

complications as they occur. In patients

49:00

with relatively minor mechanism of trauma,

49:02

there, you really have to sort of risk the, um,

49:04

um, weigh the risks and the benefits, especially

49:07

if there's, um, evidence that the patient

49:10

has a very severe, uh, anaphylactic-type

49:12

reaction to contrast.

49:18

Okay, great.

49:19

I think that might be it for the questions.

49:21

So as we bring this to a close, I want to thank

49:24

Dr. Kampalath for this lecture and thanks all of

49:26

you for participating in our noon conference.

49:29

A reminder that this conference will be

49:31

available on demand on MRIonline.com in

49:34

addition to all previous noon conferences.

49:36

Be sure to join us again on Monday

49:38

for a replay lecture from Dr. Nolan

49:41

Chu on Neuroradiology Horror Stories.

49:45

You can register for that at MRIonline.com and follow

49:49

us on social media at the MRI Online for updates

49:52

and reminders on upcoming noon conferences.

49:55

Thanks again and have a great day.