0:00

So when I'm reading a head ultrasound,

0:02

I want to know the history.

0:04

If it's a preterm infant, I'm looking

0:06

for germinal matrix hemorrhage, encephalopathy

0:08

of prematurity, things like that.

0:11

In a term infant, I'm focusing on other findings

0:14

and an infant who's over the age

0:15

of 34 weeks gestational age.

0:17

The likelihood of germinal matrix hemorrhage is much lower

0:21

and so we're looking for typically other, uh, abnormalities

0:25

to, to answer or screen for in those infants.

0:29

So a reminder of the papilla grading

0:31

of germinal matrix hemorrhages in premature infants.

0:34

So a grade one germinal matrix hemorrhage will be hemorrhage

0:37

that is confined to the coth thalamic groove.

0:40

Grade two, you have intraventricular extension without

0:44

ventricular magaly.

0:46

Grade three is where you have intraventricular hemorrhage

0:48

related to germinal matrix hemorrhage plus

0:51

ventricular magaly.

0:52

There can be some confusion

0:54

between post hemorrhagic hydrocephalus

0:56

and grade three germinal matrix hemorrhage,

0:58

especially among my residents.

1:00

So in order to call it a grade three germinal matrix

1:02

hemorrhage, it has to be a at the time

1:05

of presentation of hemorrhage.

1:06

So, um, you have germinal matrix hemorrhage filling the

1:09

ventricles plus ventricular mely at the time of diagnosis

1:14

on follow-up studies.

1:15

We'll talk about post hemorrhagic hydrocephalus in a little

1:17

bit, but the blood itself can cause ventriculitis and lead

1:22

or plugging of, uh, of the cerebral aqueducts.

1:25

And then you can get subsequent, uh, hydrocephalus.

1:28

So grade three is when you have blood plus dilation

1:32

of the ventricles at the time of presentation of hemorrhage.

1:37

Grade four germinal matrix hemorrhage is not called grade

1:40

four germinal matrix hemorrhage anymore

1:41

because they used to think it was blood extending

1:44

through the append of ventricular lining into the

1:47

periventricular white matter.

1:48

And we now know that that's not the case.

1:50

It is a per ventricular hemorrhagic venous infarction,

1:53

so not blood extending through the append lining.

1:57

Most of my NICU colleagues still want us

1:59

to say grade four germinal matrix hemorrhage just so

2:03

that they can kind of fit the, um,

2:05

infant into their carrying algorithms.

2:07

But they also understand

2:08

that it's now a more appropriately called periventricular

2:11

hemorrhagic venous infarction.

2:14

Um, so an example of what that looks like,

2:17

so not grade four germinal matrix hemorrhage,

2:19

it is now periventricular hemorrhagic venous infarction

2:23

where you have that abnormal hyper echogenicity related

2:26

to venous hemorrhagic infarction in the

2:29

periventricular white matter.

2:31

And again, just a reminder of why this happens.

2:34

You have these teeny tiny like thread like venous structures

2:38

that with a little bit of blood pressure

2:41

or heart rate instability, you can get venous stasis

2:44

and that leads to hemorrhagic venous and infarction.

2:48

So, uh, formally known

2:50

as grade four germinal matrix hemorrhage, periventricular,

2:53

hemorrhagic venous infarction is what we call

2:55

that more appropriately these days. It has a

2:58

Typical appearance as that blood ages over time.

3:02

And this patient unfortunately is a nice example

3:05

of us following that, uh, evolution

3:08

of the hemorrhagic venous infarction over time.

3:10

So at the time of, uh, acute presentation,

3:13

the per ventricular white matter will be hyper coic, um,

3:18

at the side of the hemorrhagic venous infarction.

3:21

Over time, encephalomalacia develops

3:24

and that, uh, echogenic focus will turn into a

3:28

hypoechoic focus and then it will become anti coic as

3:31

that blood evolves over time as that evolution occurs.

3:35

Typically that cystic space will communicate

3:38

with the lateral ventricle

3:39

and that's when it's called the po and cephalic cyst.

3:42

So you can see this abnormal, uh,

3:45

cystic structure communicating

3:46

with the frontal horn lateral ventricle

3:48

as a po and cephalic cyst.

3:51

I wanna distinguish that from post

3:53

hemorrhagic hydrocephalus.

3:55

So, uh, post hemorrhagic hydrocephalus results typically

3:58

from germinal matrix hemorrhage.

4:01

The hemorrhage irritates the

4:02

ventricular or epidermal lining.

4:04

It plugs up the arachnoid granulations

4:07

and impedes reabsorption of cerebral spinal fluid.

4:10

And then you might also have hemosiderin

4:13

or clot physically blocking the flow of CSF.

4:16

So a reminder of the normal flow of cerebral spinal fluid.

4:20

Um, it goes from the lateral ventricles

4:23

down into the cerebral aqueduct

4:25

and this is the most common location where blood, uh,

4:28

will physically cause an obstruction

4:30

of the ventricular system.

4:32

So it's kind of a multifocal multifold process going

4:36

on in these infants.

4:37

Um, this is an, uh, an example of an MRI

4:40

where you can actually see

4:41

that low signal hemorrhage blocking that cerebral aqueduct.

4:45

Um, we can see that in infants that ultrasound

4:48

and we will follow the size of ventricles over time.

4:53

Um, a couple of words about encephalopathy of prematurity

4:56

or white matter injury of prematurity.

4:58

Uh, this is, uh, like a watershed type infarct

5:02

that happens in extremely premature infants.

5:05

It's in the per ventricular location.

5:07

The location is classic, so at the frontal

5:10

and posterior aspects of the lateral ventricles,

5:13

the periventricular white matter, um,

5:16

normally your periventricular white matter

5:19

after one week of age will be less echogenic than the

5:22

adjacent choroid plexus.

5:24

Um, I will show you an example on the next slide about

5:26

what we call flaring.

5:28

So prior to one week of life, you may have this, uh,

5:32

normally hyper coic appearance, especially

5:34

of your posterior parietal occipital white matter in the

5:37

per ventricular region.

5:39

So this is the same infant who was, um, imaged twice,

5:43

once on day of life, one for concerned

5:46

for intracranial hemorrhage,

5:47

and then we image this infant one week later

5:49

and look at the echogenicity

5:51

of the posterior per ventricular white matter on day

5:53

of life one compared to, uh, after one week of age.

5:57

So it's the same echogenicity

5:59

as your choroid plexus prior to one week of life.

6:02

After one week of life it becomes h hypo coic compared to

6:06

that choroid plexus.

6:07

So just be careful calling, uh, white matter injury

6:10

of prematurity prior to one week of life.

6:12

You don't wanna call normal variant flaring, hyper genicity

6:18

a word about the extra axial spaces.

6:20

So especially when we are looking at our mastoid view at the

6:23

posterior fossa or when we are looking at the subarachnoid

6:26

and uh, subdural spaces at the vertex, a reminder

6:30

that the subdural space is a potential space.

6:32

So we don't typically see the subdural space

6:35

unless something is abnormally located in

6:38

that subdural space.

6:40

Our, um, text part of our protocol will get, um,

6:43

magnified images of the extra AAL spaces at the vertex,

6:47

looking at the subarachnoid versus subdural space, looking

6:50

for any abnormal collections to distinguish

6:54

between the subdural space

6:56

and the subarachnoid spaces to look

6:58

for either a subdural collection or subdural hemorrhage.

7:01

Um, we are looking for a couple of things.

7:04

Number one, we don't wanna see any displaced arachnoid

7:08

monitor, so we want to be able to see the, uh,

7:12

bridging veins and arachnoid granulations extending from the

7:15

surface of the brain all the way to the inner table

7:17

of the calvarium.

7:19

We don't wanna see any displacement towards the brain

7:21

parenchyma and we definitely don't wanna see any

7:23

displaced arachnoid matter.

7:25

So here is an example of that.

7:26

So this was an infant who, uh, has subdural collection,

7:31

so pay attention to a couple of things.

7:33

Um, on this ultrasound,

7:34

this white arrow is showing you displaced arachnoid mod.

7:39

So typically this arachnoid mater is pushed all the way up

7:42

to the inner table of the calvarium.

7:44

So we don't actually see this structure.

7:46

So this purple arrow is pointing to the subdural space.

7:49

There's some, an coic fluid pushing

7:51

that arachnoid monitor down towards the brain.

7:55

When if we were to put color doppler imaging on,

7:57

we would see vascular structures extending only

8:00

to the displaced arachnoid matter, not all the way

8:03

to the calvarium, which we would like to see.

8:05

So that's what this blue arrow is pointing to on MRI.

8:09

We can see this, um, on T two weighted sequences,

8:12

but it has to be, uh, like a, a super fluid sensitive

8:16

MRI sequence to be able to see that level of detail.

8:19

So again, the white arrow on the sagittal uh, cysts

8:22

or fiesta super T two weighted sequence, you can see

8:26

that wide arrow is pointing

8:27

to the displaced arachnoid monitor.

8:29

We see, uh, bridging veins displaced towards

8:32

the brain parenchyma.

8:34

Normally they should extend all the way to the inner table

8:36

of the calvarium and the purple arrow is pointing to

8:39

that subdural space.

8:40

So this is a subdural collection in an infant.

8:43

This patient for some reason, the clinicians

8:46

before they got the MRI got a ct,

8:48

which does not give us the level of detail that we need.

8:51

So a reminder that an infant's

8:53

optimal imaging is either ultrasound or MRI.

8:57

Uh, so head ultrasound is for screening, MRI is

9:00

for diagnosing, um, in much greater detail

9:04

'cause we can see much better and we can see signal changes

9:07

of ischemia and hemorrhage, et cetera.

9:09

Um, CT is really not, not great

9:11

unless your only question is,

9:13

is there hyper attenuating hemorrhage And compare

9:17

that example to this case.

9:18

So this is a case of benign macro cranium infancy

9:21

where the extra axial spaces at the vertex are large,

9:25

but we see bridging structures extending all the way

9:28

through these extra axial spaces.

9:30

So this blue arrow is showing you a bridging vein extending

9:33

through that subarachnoid space.

9:35

So we have those structures going all the way from the

9:37

surface of the brain through the inner table

9:39

of the calvarium, and we also don't see any displaced

9:42

arachnoid moderate in this infant.

9:44

I also wanna point out that this is a specific

9:46

patient population.

9:48

So benign macro cran of infancy is a normal finding.

9:51

These patients typically have big heads

9:54

and if you look at mom

9:55

and dad who are in the room with you, um, one

9:58

of them will typically have large head

9:59

circumference size as well.

10:01

So these are infants who are typically six

10:03

to nine months of age.

10:04

They have a totally normal neurological examination.

10:08

If you have an infant in the NICU

10:10

who is younger than six months of age

10:12

who maybe was premature and has been in the NICU feeding

10:15

and growing for their entire life,

10:17

that is not gonna be benign.

10:18

Macro cranium of infancy.

10:19

If you see large subarachnoid spaces in those infants,

10:22

that typically is gonna be a level of atrophy, um, related

10:26

to, um, their prematurity.

10:29

So in summary, uh,

10:31

most germinal matrix hemorrhage occurs

10:33

within one week of life.

10:34

And that is why we typically do screening head ultrasounds

10:37

at one week of life.

10:39

We want to see most of the cases of hemorrhage

10:41

that are gonna occur and then we'll do screening head

10:44

ultrasound again at about four to six weeks of age.

10:47

And then at term equivalent

10:48

or the time of discharge, a reminder that grade four

10:53

germinal matrix hemorrhage is no longer

10:55

actually called grade four germinal matrix hemorrhage.

10:58

The more appropriate term is periventricular

11:00

hemorrhagic venous infarction.

11:03

There are a lot of normal variants

11:04

that we can see at head ultrasound, especially flaring

11:08

and don't call that pathology erroneously.

11:12

Make sure you pay close attention to the extra axial spaces,

11:15

subarachnoid versus subdural space.

11:17

And if you can see a vascular structure,

11:19

make sure you interrogate it with color doppler.

11:22

Or if you have a machine with some sort

11:24

of microvascular imaging, um, like a B flow

11:27

or a superb mi microvascular image, um, make sure you use

11:31

that to ensure vascular patency.

11:34

With that, let's go on to several examples

11:37

to illustrate some of these things that we've just learned.