0:00

So section one is, uh, on coronary artery disease,

0:04

pathophysiology and associated imaging approaches.

0:08

So as most of us are probably really familiar

0:11

with coronary artery disease results from plaque forming in

0:15

our coronary arteries.

0:17

And you can see a depiction

0:18

of this here in the figure on the left.

0:20

And this often starts as soft plaque,

0:23

and it continues to narrow vol lumen as more

0:26

and more soft plaque builds up.

0:28

And then what we really are really worried about in an acute

0:31

myocardial infarction is when that plaque ruptures.

0:34

So it's a highly inflammatory state,

0:36

and sometimes the fibrous cap around that plaque ruptures,

0:41

and that's what causes an acute myocardial infarction when

0:44

you get a complete occlusion

0:46

or near complete occlusion of a coronary artery due

0:48

to a blood clot related to that plaque rupture.

0:51

Now there's a long cascade that happens

0:53

before that acute myocardial infarction occurs,

0:57

which is kind of what we're trying to detect and,

0:59

and prevent, because we obviously wanna limit

1:02

patient's risk to heart attack.

1:03

So we kind of try to catch people along some part

1:06

of this ischemic cascade that you see here on the right.

1:09

And you can see just as we go up to the right on the graph,

1:14

uh, we go from normal function to,

1:17

as the coronary arteries get more

1:18

and more narrowed, you can end up

1:20

with perfusion abnormalities.

1:21

You can end up with cardiac diastolic dysfunction, strain

1:26

abnormalities in the myocardium systolic dysfunction.

1:29

And then eventually, if

1:30

and when the, the coronary artery gets almost completely

1:33

occluded or completely occluded,

1:35

you can get EKG abnormalities.

1:37

And then, you know, chest pain, of course can come with more

1:39

and more severe occlusion.

1:42

So we have a wide variety of diagnostic tools to try

1:45

to catch people somewhere along that ischemic cascade

1:48

of coronary artery disease.

1:49

And, uh, you can see just a bunch of them here.

1:52

We have increasing utilization of coronary CT angiography,

1:56

CT fractional flow reserve.

1:58

Obviously, invasive angiography has always been a mainstay

2:01

of coronary artery disease evaluation.

2:03

And increasingly PET is used to assess ischemia.

2:08

SPECT has been a mainstay for a long time,

2:09

and echo is, is really a workhorse in cardiac evaluation.

2:13

So why would we choose cardiac Mr Uh,

2:16

when we have all these tests?

2:17

Well, there's several reasons.

2:19

Probably most relevant is it can be a one-stop shop

2:23

for cardiac evaluation.

2:24

And that's one of the reasons that I really like it

2:26

and a lot of people really like it for their patients.

2:28

Cardiac MRI is the gold standard for functional evaluation.

2:31

So if you really wanna pin down

2:33

what someone's cardiac volumes and diastolic volume

2:36

and systolic volume, what their ejection fraction is,

2:39

what their myocardial mass is,

2:40

cardiac MR is the gold standard tool for that.

2:44

As we'll see throughout the course today,

2:46

it's an excellent tool for assessing cardiac motion

2:48

and regional wall motion abnormalities,

2:50

which become very important in evaluation

2:52

of ischemic injury to the heart.

2:54

And then we have all these other potential tools

2:57

that I call myocardial tissue

2:58

Characterization tools.

3:00

Some people, you know, talk about

3:01

myocardial mapping, that sort of stuff.

3:03

But we can really, in both a qualitative

3:05

and quantitative fashion, start

3:06

to evaluate things like cardiac perfusion, stress,

3:09

perfusion, MRI, which we'll have a whole section on here

3:12

later, myocardial edema and scar and viability imaging.

3:16

So just to kind of give you a flavor of, of

3:19

what this looks like, I just

3:20

want to go through a quick case.

3:21

This is a 71 year old woman

3:23

with acute myocardial infarction.

3:25

And how do you approach a case like this?

3:28

What's the general overview?

3:29

Well, first you wanna look at these syn imaging.

3:32

These are balanced, steady state free procession syn imaging

3:35

in a short axis view here.

3:37

This is the short axis of the heart where we have sort

3:39

of these circles, our donut shapes of the myocardium.

3:42

And really what we're looking for here, we can use these

3:45

to measure overall function.

3:47

But in the setting of ischemic evaluation,

3:49

we're really looking for regional wall motion abnormalities.

3:51

And I wanna draw your attention to this frame right here

3:56

where we can see maybe a little bit of

3:59

what we call hypokinesis here in the inferior segment here

4:02

in the mid short axis view.

4:04

The next thing that we would do in a patient like this is

4:07

look for what's called late gadolinium enhancement.

4:09

And then a edema, which I'll show you on the next slide.

4:12

This is the same patient

4:13

and these are late gadolinium enhanced images

4:15

where we can see kind of maybe in that region

4:18

where we saw a little bit of hypokinesis,

4:20

we have what's called late gadolinium enhancement here in a

4:24

sub endocardial distribution right below

4:27

the endocardial border here.

4:28

That's extending, you know, pretty significant percentage

4:31

of the inferior segment

4:33

and inferior septal segments here see the same view on a,

4:36

what's called a two chamber of the heart.

4:38

So the two chambers here are left ventricle and left atrium.

4:41

And then if we line this up with AT two map,

4:43

so this is actually a quantitative map of T two values

4:46

of the heart, we can see

4:48

that there's actually elevated T two in that same segment.

4:51

And so this would be consistent in this patient

4:53

with an acute myocardial infarction.

4:55

So we're gonna be hitting on all those themes today in the

4:58

course, we're gonna learn more about each one

5:00

of those imaging approaches and tools

5:03

and how that can be used

5:04

to determine things like acute versus, uh,

5:07

chronic infarction viability,

5:09

and maybe some other differential diagnoses that come along

5:12

with these findings.

5:14

So in general, when we do CMR in patients

5:17

with ischemic heart disease,

5:18

we should really be answering a few important questions.

5:21

Is there ischemia? Is there an infarct?

5:23

What's the acuity of the process?

5:26

Is there functional significance?

5:27

Have, have we impacted cardiac function at all?

5:30

And is the involved myocardium viable?

5:33

That's been a very important use of cardiac mr.

5:36

And we'll touch on that a little bit more in the next talk.

5:38

And then importantly, are there complications?

5:41

You know, has the myocardial injury led to something else,

5:44

an aneurysm, uh, rupture, uh, thrombus?

5:47

Uh, we will also explore some

5:48

of those complications later today.

5:50

Finally, I just want to end this portion by saying,

5:53

you know, not all things

5:54

that cause chest pain are related to

5:56

Necessarily ischemia.

5:58

There's something called myocardial infarction

6:00

with non-obstructive coronary arteries, manca.

6:03

We'll see a few case examples of that.

6:05

But what I like about this slide

6:07

where we're talking about manca,

6:09

it also gives a nice overview of other causes of chest pain

6:12

that you have to consider in all these patients.

6:15

So really we're trying to not only sort

6:17

of rule in ischemic heart disease,

6:19

but we're trying to rule out

6:21

or perhaps rule in some other causes of chest pain.

6:25

Things like myocarditis, takotsubo, cardiomyopathy,

6:28

and then a few other disease processes, uh,

6:31

that occur outside the heart.

6:32

Things like pulmonary embolism or something like that.