0:01

This next case is a younger patient

0:04

and while they were admitted to the hospital,

0:06

a CT angiogram was performed, which led to an MRI

0:10

and I think it's a nice opportunity

0:12

to look at the myocardium.

0:14

Um, so as you can see, there's a prior bypass surgery.

0:17

We haven't, at least on this view,

0:19

I haven't shown you everything,

0:20

but Lima, you have an LED, you have a lot

0:23

of disease in the RCA, which may be occluded,

0:25

and then you have, um, some circumflex disease

0:28

and probably a stenosis.

0:31

Um, but most importantly when you look at the myocardium,

0:35

and we have limited cardiac cycle phases,

0:37

but we have enough, um, you can see

0:39

that there's some thinning of the inferior wall.

0:41

So let's just switch from the arteries to the myocardium

0:45

and take a look at these.

0:47

And what you're gonna see here is that,

0:49

and I just, I think I have like a six phases here.

0:52

So not even a complete cardiac cycle, uh,

0:54

but when you page through these inin mode, you can see

0:57

that the rest of the heart, at least in the phases

0:59

provided, is moving a little bit.

1:01

And the inferior wall is not contracting much.

1:04

You can also see when you look at the wall thicknesses,

1:07

let's maybe bump this up to around eight millimeters, uh,

1:10

and stop the cine.

1:11

The myocardium doesn't thicken as much,

1:15

but it's also not calcified.

1:17

Uh, there's no interventricular thrombus.

1:19

Um, so just some mild thinning.

1:22

And the reason I wanted to bring this up is

1:24

that the contrast resolution of CT is inferior

1:27

to that of an MRI.

1:28

So it's about 25 to one CNR

1:31

for a late galium enhancement Mr Image.

1:33

It's about five to one at best for a ct.

1:36

And what you're seeing here on this delayed phase, uh, image

1:39

of the, uh, cardiac MR that was performed subsequently,

1:43

you can see there's a sub endocardial about 50%

1:46

wall thickness scar.

1:47

Um, so while there's hypokinesis, there's still some, uh,

1:50

myocardium left and you can see that it's much easier to see

1:53

that late enhancement on a late phase when an MRI,

1:56

where the normal myocardium is nulled,

1:58

but still a noisy image,

2:00

but much better contrast to noise ratio.

2:02

So if you're gonna look at myocardium on a ct,

2:04

just know it's a little bit limited.

2:06

And so you're gonna focus on what you know for sure,

2:07

which is thinning in wall motion.

2:10

And in this case,

2:11

we didn't even attempt to do delayed image.

2:13

We probably didn't know at the time of acquisition.

2:15

But if you did and you did a delayed image,

2:17

you'd want to give enough contrast.

2:18

Wait long enough to get a nice announcement.