0:01

This was a child with primary biliary cirrhosis

0:04

and hepatic failure who presented with obtundation.

0:10

Looking at the FLAIR scan, I must admit that although

0:13

I see some focal areas of high signal intensity in the

0:16

subcortical white matter, I'm not all that impressed

0:20

with anything to account for the patient's obtundation.

0:24

Certainly, with these bright

0:25

areas of high signal intensity.

0:28

This would not be normal for a child,

0:30

and I'd be worried about a vasculopathy.

0:33

This might be a pattern that is seen with

0:35

migraines, but it seems like a lot of injuries.

0:38

I wanna know exactly what you know, whether

0:40

the hepatic disease could be causing some

0:43

sort of vasculopathy associated with it.

0:46

On the diffusion-weighted scan, you notice that there

0:50

is this accentuation once again of the difference

0:54

between the gray matter and the white matter.

0:58

So I'm looking at the DWI saying, is this just a really

1:01

good-looking DWI with good gray-white differentiation?

1:05

One would go back to the FLAIR scan, and you know,

1:09

it does look like there's some thickening

1:12

of the gray matter here, that there may be some

1:16

cerebral gray matter edema that may be pathologic,

1:22

and may account for the patient's obtundation.

1:25

The next step would be to look at the ADC map.

1:28

So this is the ADC map that corresponds

1:30

to the diffusion-weighted imaging.

1:33

And what I see on the ADC map is dark signal intensity

1:37

in the cortex diffusely, which corroborates my concern

1:44

that there is too much hyperintensity to the cortex

1:50

on the DWI image. So remember, this is DWI.

1:53

This is ADC.

1:55

On the ADC image, dark signal is abnormal.

1:58

On the DWI, bright signal is abnormal.

2:00

Here, I'm seeing cortex, which is darker than

2:04

expected, and therefore there is cytotoxic

2:07

edema being demonstrated in this patient.

2:11

This patient's—it’s gonna be seen over here as well

2:15

in the inferior frontal lobe, there's a difference

2:18

in the dark signal of the cortex here versus the

2:21

remainder of the brain, where it's not as dark.

2:25

And that's seen in the parietal regions here,

2:27

and most impressively high up along the vertex.

2:31

This was another patient who had hyperammonemia,

2:35

secondary to primary biliary cirrhosis.

2:38

And the inability to clear the ammonia

2:41

from the blood, leading to cytotoxic edema.

Case: Hyperammonemia on MRI

HIDE

Prev Next

Interactive Transcript

Pro Tip: Click on a word in the transcript to jump to that point in the video