0:01

Applying the knowledge that you

0:02

learned, let's analyze this case.

0:06

This case was a patient who had

0:09

pain, belly pain and chest pain.

0:13

So they did a CT angiogram of the

0:16

chest to look for aortic pathology.

0:19

And they also did a routine belly

0:22

to look for an acute abdomen.

0:27

This is an image from the routine belly.

0:30

And this is an image from the

0:32

CT angiogram of the chest.

0:35

So what do you think?

0:36

went wrong here.

0:38

Take a look at the images.

0:41

Here's what I asked the tech.

0:42

I said, I asked the tech, where did you trigger from?

0:45

And he sent me those trigger images.

0:46

And these are the images that they sent me.

0:52

So what was the issue?

0:53

We have a few options.

0:55

Region of interest was placed in the false lumen.

0:58

Patient had low cardiac output.

1:01

Tech was incompetent and the patient moved.

1:05

The answer is low cardiac output.

1:09

Be very careful in blaming the tech because

1:11

it's often factors that are very technical.

1:15

Patient moving is always a problem, but

1:17

the region of interest didn't show that.

1:20

And yes, the ROI could have been in

1:22

the false lumen, but the problem wasn't

1:25

that the ROI was in the false lumen.

1:26

If the ROI is in the false lumen, the scan starts late.

1:30

Here, the scan started early.

1:31

See the chest scan started early.

1:34

I mean, in a sense, it didn't start early.

1:36

It started early only in relation to

1:38

the contrast because see that the

1:40

pulmonary artery is nicely pacified.

1:42

Aorta is not touched.

1:44

When we do the routine belly, which was done with

1:47

a 70-second delay from the time of injection,

1:50

you have almost perfect arterial pacification.

1:54

So the issue was low cardiac output.

1:57

This patient actually had a type A dissection,

2:00

which also led to a myocardial infarction,

2:04

which also led to a low cardiac output, which

2:07

is responsible for the problem that we see.

2:10

Okay, so let's.

2:12

Continue applying principles, and although

2:15

this is not cardiac, I think, um, we should

2:19

think of the principles that we've learned.

2:22

To evaluate distal renal arteries for medium

2:24

vessel vasculitis, we must increase contrast

2:26

volume, increase injection rate, use saline

2:29

bolus, lower KVP, and all of the above.

2:33

So, what am I asking?

2:34

I'm asking if you have a protocol that you've set

2:39

up for a CT angiogram and you want to now vary that

2:42

protocol to look for medium vessel vasculitis

2:45

in the renal arteries, which has second-order

2:47

arteries, that you want to look for abnormalities.

2:50

What are you going to do differently?

2:52

And the answer is you're going to do all of the above.

2:54

You're going to increase the contrast volume.

2:56

Because by increasing the contrast volume, you're

2:58

going to increase the peak maximum enhancement

3:01

and also the plateau along which it would apply.

3:05

You'll increase the injection rate, which

3:07

will reduce the time to peak, whilst

3:11

also increasing the peak maximum enhancement.

3:13

The saline bolus will tighten the

3:15

bolus and push things together.

3:16

Lower KVP will give you more iodinated bang for

3:20

your buck, so you would do all of the above.