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Okay, so we're talking about

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abdominal aortic aneurysm ruptures.

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This is just another case of an

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abdominal aortic aneurysm rupture.

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You can see that there's a very large

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abdominal aortic aneurysm and a large volume

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of free retroperitoneal fluid of higher

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attenuation consistent with blood products.

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This one was imaged with a delay,

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not that you would need this.

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Trust me, but you can actually see the

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extravasation of contrast from the aorta.

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In this case.

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You want to make sure the patient's

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not looking at the light.

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This has got to move out of your CT

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scanner into the OR as soon as possible.

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Of note again is that you have this large

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volume of retroperitoneal blood that has.

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Not expanded iliopsoas muscle that's in

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that perirenal space that you're actually

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seeing, um, actively bleeding in this case,

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somewhat dramatic cardiovascular surgery run.

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That is an absolute emergency.

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But let's talk about the aorta bit.

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Here's another case of a very large abdominal

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aortic aneurysm with rupture and a lot of

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retroperitoneal perirenal space hemorrhagic

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blood products, but I always like to talk about the

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normal appearance of blood vessels and what we're

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seeing here because it sometimes confuses my trainees.

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Note that the calcifications in a blood vessel are

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always on the intima of the blood vessel in a patient.

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So when you see this darker interluminal

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substance, it's not a dissection.

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I think this is kind of job security for us

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because sometimes the surgery residents come back

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here and they're like, is there a dissection?

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And I'm like, no, no, no, no, no.

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That's just atherosclerotic schmutz

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basically on that aortic wall.

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So we do use the presence of calcifications

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to tell us where the intima is in this case,

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and we'll go into that again in a moment.

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Um, but we also will talk about

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that in the level of dissection.

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Again, these calcifications are on the intima,

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and that will tell you that this indeed

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is a dissection because that intima is.

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Peeled off here and is within the lumen

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as opposed to our case of the abdominal

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aortic aneurysm where the intima is still

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in the circumferential around the aorta.

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What happens in an enlarged blood vessel is that

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as you increase the size of the blood vessel, there

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becomes much more turbulent flow, so there is a lot

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less laminar flow, and as a result in the periphery

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of these blood vessels, you can have mural thrombus,

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basically, you know, all forms of cellular blood and

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or atherosclerotic disease will be in that location.

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Aortic aneurysms are when they dilate more

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than three centimeters, and a large aortic

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aneurysm that would be this large would

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have an extremely high risk of rupture.

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Those are the patients who usually will get an aortic

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stent graft when it is recognized, and hopefully

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that will occur before the patient ruptures.

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I just want to bring in something

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for your engineers here.

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It is crazy town, but this is the appearance of the

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aorta showing you that there is a lot of turbulent flow

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and result in that sedimentation along the periphery.

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It's fun.

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It's fun.

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So aortic aneurysm rupture occurs and is

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increased in probability by the size of the aorta.

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Um, we expect a large blood vessel to have less

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laminar flow and to enhance heterogeneously with

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possibilities of peripheral atherosclerotic thrombus.

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And we are going to identify the intima of a

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blood vessel by using those calcifications.

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The bleeding of an abdominal aortic aneurysm

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will be in the retroperitoneum in that

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perirenal space, PERI, and will result in

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retroperitoneal bleeding from the rupture.