0:01

We've discussed the indications

0:03

for surgery for epidural hematomas.

0:05

I do want to quote Youmans neurosurgical

0:09

textbook for subdural hematomas.

0:12

For subdural hematomas, an acute subdural hematoma with

0:15

thickness greater than 10 millimeters or midline shift

0:18

greater than 5 millimeters is an indication for surgery.

0:22

So once again, this stresses to the residents,

0:24

measure the thickness of the collection,

0:27

measure the degree of midline shift

0:29

at the level of the septum pellucidum.

0:31

And those patients who have an unfavorable Glasgow

0:34

Coma Scale may also go to surgery more readily.

0:37

I just want to point out, once again, that although

0:40

we think about an epidural hematoma as an arterial

0:42

bleeder, and therefore maybe something that's

0:45

uh, worse prognosis. For the epidural hematoma,

0:50

the thickness was 15 millimeters, whereas for

0:53

this subdural hematoma, it's 10 millimeters.

0:56

So that shows you that the subdural hematoma

0:59

actually has potentially a worse prognosis,

1:03

and they will intervene earlier for both of them,

1:06

midline shift greater than 5 millimeters on CT scan.

1:10

Those patients who are comatose and are doing

1:14

poorly, who have a subdural less than 10 millimeters,

1:18

or midline shift less than 5 millimeters, but are

1:21

deteriorating rapidly by virtue of going downward

1:26

in the Glasgow Coma Scale, or having fixed and

1:29

dilated pupils, or increasing intracranial pressure.

1:33

For those patients, they will

1:35

intervene even with a smaller size

1:37

subdural hematoma on the CT scan.

1:41

So remember that on the CT scan, we're going to be

1:44

looking for a crescentic collection that crosses the

1:47

suture and which is unassociated with a fracture.

1:53

We measure the midline shift on this case, and both the

1:56

collection itself is greater than 10 millimeters in width.

2:00

I can see that, and the midline shift

2:03

is going to be greater than 5 millimeters

2:05

at the level of the septum pellucidum.

2:08

So this is going to be a surgical case.

2:10

Here is another example of

2:12

an isodense subdural hematoma.

2:16

In this case, a patient who had chronic anemia.

2:19

And so, this was an acute subdural hematoma that

2:24

was isodense because the hematocrit was low,

2:27

secondary to the patient's leukemia.

2:31

In this case, once again, there's a lot of midline shift.

2:33

We're not at the level of the septum pellucidum,

2:36

but we can see that this is going to be greater

2:38

than 5 millimeters in shift and greater than

2:43

10 millimeters in thickness in axial width.

2:48

I mentioned previously, on the case before, the

2:54

finding known as the swirl sign, which indicates

2:58

that the patient is having ongoing hemorrhage,

3:02

and this can occur in subdural or epidural hematomas.

3:07

Ongoing hemorrhage in a parenchymal

3:11

hematoma may be seen on a CTA.

3:15

So when does this happen?

3:17

We often requested CTAs in patients

3:21

who have parenchymal hemorrhages, in which

3:25

they are not sure that it's due to trauma.

3:28

And they're looking for an aneurysm or

3:30

an arteriovenous malformation or a fistula

3:33

that may be the source of the hematoma.

3:37

In this case, we have a hemorrhage that is

3:40

in the posterior globus pallidus region

3:43

and putamen region that is

3:46

likely from a hypertensive bleed.

3:49

But what we're also seeing is the spot sign, and that is

3:53

a blood vessel that is leaking within the collection.

3:58

This spot sign is an indicator of ongoing

4:03

hemorrhage, and it indicates that it is

4:06

likely that this hematoma will expand.

4:09

So it behooves the clinicians

4:12

to do a repeat scan in a short time

4:16

interval to see how large it's going to be.

4:18

Remember that for a hematoma, they're going to measure

4:20

the AP diameter, the transverse diameter, and the

4:24

superior-inferior diameter, and if it's over 30 to

4:27

50 cc's, it's going to be an indication for surgery

4:30

according to Youmans' Neurological Surgery textbook.

4:35

Now, this is a little bit more subtle, right?

4:37

When we look at this case, initially, you may blow this off.

4:41

However, what we see is that although the sulci are

4:44

going all the way out to the periphery on the right

4:48

side, on the left side, the end of the sulci is here.

4:53

We're actually seeing the cortical margin here.

4:56

This is a little bit more subtle.

4:58

Isodense subdural hematoma that's seen on multiple sites.

5:02

It's actually quite big.

5:05

It's not showing midline shift, at least on these images.

5:08

So this is, again, one of the things to be careful about,

5:11

is to try to identify the sulci going all the way out

5:14

to the periphery, try to identify the cortical surface

5:18

going all the way out to the periphery as well in

5:20

order to avoid missing an isodense subdural hematoma.

5:26

Another case.

5:27

Swelling of the brain, loss of the gray-white differentiation.

5:30

101 00:05:32,990 --> 00:05:35,650 This is not an isodense subdural hematoma.

5:35

This is a patient who has had severe head

5:39

trauma, leading to diffuse increased intracranial

5:43

pressure and anoxic-ischemic injury.

5:47

Note that the ventricles are small in size.

5:49

We barely see them.

5:50

We don't really see basal cisterns.

5:52

The whole brain is swollen, and this is one of the worst

5:58

prognostic signs in a patient who has had head trauma.

6:04

So this is diffuse cerebral swelling, usually

6:07

associated with an increase in intracranial pressure.

6:12

And, as you can see here, we've lost

6:15

the basal cisterns around the medulla.

6:18

And there is herniation of the cerebellar

6:20

tonsils through the foramen magnum.

6:23

This is an emergency.

6:25

The patient needs to be decompressed, needs to have

6:28

the increased intracranial pressure treated.

6:30

Otherwise, this herniation will compress the medulla

6:33

to such a significant degree that the patient will stop

6:37

breathing and likely go into a cardiopulmonary arrest.

6:42

So, absence of gray-white differentiation

6:46

due to diffuse cerebral swelling, increased

6:49

intracranial pressure with tonsillar herniation

6:53

inferiorly through the foramen magnum.

6:56

Another case, here's a patient where we see

7:00

multiple areas of hemorrhage in the brain that is

7:04

located at the gray-white matter junction.

7:08

This is an example of what we see

7:12

on CT with diffuse axonal injury.

7:16

This is a rotational shearing injury

7:20

of the white matter at the gray-white matter junctions.

7:24

This is a very poor prognostic sign.

7:27

Often, although there are just these tiny little spots

7:30

of hemorrhage, the patient is comatose because they've

7:32

had such a severe traumatic injury to the brain.

7:35

And over the course of time, what you see is

7:38

these hemorrhages expand, and new hemorrhages

7:41

appear that were not there on the initial scan.

7:45

This is also associated with increase in

7:47

intracranial pressure, and the patients will have

7:51

the significant changes associated with that.

7:54

There is a grading system for diffuse axonal injury.

7:59

These types of injuries,

8:00

unassociated with involvement of the

8:02

corpus callosum, would be Grade 1.

8:05

When you have involvement of the

8:07

corpus callosum, Grade 2.

8:09

And when you have involvement of the brainstem,

8:11

usually at the midbrain, it's Grade 3.

8:15

And obviously, the higher the grade, the worse the prognosis.

8:16

153 00:08:19,565 --> 00:08:21,985 When you look at the corresponding MRI scan

8:21

of that same patient, you are more

8:25

aware of just how diffuse the injury is.

8:30

Note that these areas in the frontal region,

8:34

which we're seeing better or equally on the

8:37

CT scan, are just the tip of the iceberg.

8:40

Here on the susceptibility-weighted scan, which is

8:43

the most sensitive pulse sequence for the

8:45

presence of hemorrhage, we have innumerable

8:49

areas of shearing at the gray-white matter junctions,

8:53

as well as the basal ganglia, as well as portions

8:57

of the splenium of the corpus callosum here.

9:00

Here is involvement of the corpus callosum.

9:02

So, we've now converted from a grade 1 injury

9:05

that was seen on the CT scan to grade 2 injury

9:10

by virtue of involvement of the corpus callosum,

9:14

and we get the sense that this is a far worse

9:17

diffuse injury than what was seen on the CT scan.

9:22

And this is the great value of

9:24

MRI for evaluation of patients in trauma.