0:01

The next important topic to review is the difference between ischemic and non

0:05

ischemic patterns of enhancement on cardiac MRI.

0:09

So, cardiac MRI is very often used

0:13

to evaluate the patient with cardiomyopathy,

0:16

and one of the key differentiators in the treatment of these patients is

0:20

whether or not they have ischemic heart disease or non ischemic heart disease.

0:24

The way you can differentiate non ischemic

0:27

from ischemic disease on cardiac MRI is the pattern of late gadolinium enhancement.

0:32

On the left hand image,

0:34

you see what is kind of a classic appearance of ischemic heart disease.

0:38

The patient has subendocardial enhancement.

0:42

It's involving the lateral wall, and it's approximately 50% transmural.

0:48

So this has two of the major features

0:51

that you want to see for ischemic heart disease.

0:53

One, subendocardial location and two,

0:56

a vascular territory, in this case, the circumflex territory.

1:00

Now, in the middle and the right hand

1:02

image are two examples of non ischemic types of scar.

1:06

This patient has scar in what we would

1:08

describe as the mid wall, and this patient has subepicardial scar.

1:13

Scar right beneath the epicardial surface of the heart.

1:17

In both these cases, these are scars that you would not see with ischemia.

1:22

Ischemia, as you know,

1:23

always affects the subendocardium first and then radiates outward.

1:27

Non ischemic diseases tend to involve

1:29

the midwall or the subepicardial regions of the heart.

1:33

So these two patterns that we see here are

1:35

very common in non ischemic heart disease, and they help us say that, okay,

1:39

this patient's heart disease is not due to coronary artery disease.

1:42

In fact, there's something else going on,

1:44

and help us narrow down the differential quite a bit.

1:47

On this next slide, I'm going to summarize

1:49

some of the differences between ischemic and non ischemic scar on cardiac MRI.

1:53

Like we said,

1:54

ischemic disease subendocardial or in some cases, transmural.

1:58

If you have transmural, unfortunately,

1:59

that doesn't necessarily tell you if it's ischemic or non ischemic.

2:03

However, if you do see transmural enhancement and it's in a vascular

2:07

territory, that argues really strongly for an ischemic distribution of disease.

2:11

And then the other thing is just qualitatively,

2:13

when you look at ischemic scars on cardiac MRI, they're usually really bright

2:17

and very well-demarcated, very sharp borders.

2:20

Non ischemic scars, unlike ischemic scars,

2:23

can be any location in the wall, and they often spare the subendocardium,

2:27

although not in every single case. They do not conform to a vascular territory.

2:32

And this is a big differentiator between ischemic and non ischemic scars.

2:36

And then finally,

2:37

the LGE in patients with non ischemic scars can be faint with fuzzy edges.

2:42

So you don't often see that bright,

2:44

well demarcated late enhancement that you do see with patients who have ischemia.