AUDIO TRANSCRIPT: Someone asked me why it is that I have the computer trace all the cardiac phases when I just need end diastole and end-systole to determine the ejection fraction, and I thought that was a really good question. The reason why I have the computer trace all the cardiac phases is because it gives important diastolic information. Now I know some of you are uncomfortable looking at all of these traces so we can, for instance, shutoff the epicardial traces and we can choose to show just end diastole and end-systole so that the images look just like you and traced them, but we still get the volume versus time curve down here and you can see the different phases of the cardiac cycle. There’s systole. Here’s early filling. Here’s diastasis, and here’s active filling. This part is due to atrial contraction. Now in this healthy 28 year old, you can see atrial contraction contributes a small percentage of the total filling of the left ventricle. Now let’s contrast that with the next patient. I’m going to switch here to a patient who is a 67 year old woman who has diastolic dysfunction. You can see her ejection fraction is about the same at 63 percent. The last patient’s ejection fraction was 62 percent, and here’s the volume versus time curve, and you can see atrial contraction is responsible for a greater amount of filling of the left ventricle. That information wouldn’t be available if you only trace to end diastole and end-systole.
Now, how about another patient? This is a patient with hypertrophic cardiomyopathy. He’s got normal systolic function. You can see the ejection fraction is 57 percent, but when you look at the volume versus time curve, you can see there’s a very, very abnormal, pattern where you have diastolic filling but no diastasis, so this patient has very bad diastolic function and you can see how this patient would be in trouble if the heart rate goes up because you would put more pressure on diastolic filling. There is no diastasis period to give up.
How about patients with coronary disease? This is a patient with an ischemic cardiomyopathy.This patient has abnormal systolic function. The LV EF is 46 percent and they have abnormal diastolic function. You can see there’s no diastasis. The ventricle fills very slowly. If we look at the first pass stress perfusion, you can see that there is near global reversible ischemia. There’s a dark rim of decreased signal on all of the slices showing Ischemia, and if we look at the delayed enhanced images, you can see they’re almost normal. There’s just a little bit of scar here in the septum. This patient’s ejection fraction is 46 percent.
Let’s compare that to another patient with ischemic cardiomyopathy with a similar ejection fraction. I’m going to come here and you can see this patient’s ejection fraction is 43 percent, but has a much more normal volume versus time curve. Here you can see the period of diastasis. There is faster ventricular filling in diastole and when we look at the delayed enhanced images of this patient, you can see that there’s a big anterior and a apical infarct and I can come here on these short access images and we can actually come here and automatically quantify that infarct for you.
So I’m segmenting the endocardium and epicardium and it’s automatically determining the infarct and you can see this person has a 37 gram infarct that comprises 30 percent of the left ventricular mass. I find it really interesting that a patient like this with a big infarct has much better diastolic function than the previous patient who had almost no infarction but had a lot of hibernating myocardium.
So I hope this helps explain the value of tracing all the cardiac phases. Even if you don’t look at them when you analyze the heart, if what you see interests you, you can go to www.cardiacmri.com and you can use the software remotely to analyze these cases yourself.
Back to Videos