0:00

Talking about coronary arter calcification,

0:02

this is an important marker of atherosclerosis.

0:06

The extent

0:07

and higher the score of a calcium scoring exam correlates

0:11

with the extent of atherosclerotic black burden

0:14

and is used to predict coronary heart disease risk.

0:17

We know that coronary calcium is common on general

0:20

thoracic cts.

0:21

Even before we started doing lung cancer screening, 53%

0:25

of patients with coronary calcium found on thoracic CT have

0:29

no history of symptomatic coronary disease.

0:32

41% of patients over the age

0:34

of 40 will have coronary calcium,

0:37

and about a quarter of patients who undergo a CT examination

0:40

for pulmonary embolism will have coronary T

0:43

calcification identified.

0:45

The 2016 Society of Cardiac CT Society

0:48

of Thoracic Guideline recommends reporting coronary T trail

0:51

calcification in all patients, irrespective of the reason

0:55

for the scan being done and for patient risk status.

0:59

This could be using a visual interpretation score, non mild,

1:04

moderate, heavier, severe,

1:06

or actually doing a quantitative AON score on a regular

1:10

chest ct, which is possible with newer software tools,

1:13

including many of the new AI tools.

1:16

More recently, these tools are being used

1:18

to evaluate large cohorts of patients in your practice,

1:22

people are applying these types of AI tools to identify

1:25

and quantify coronary calcium ct, for example,

1:28

on all the chest cts in their PACS database within say the

1:32

last five years, to try

1:33

and identify patients at high risk

1:35

for cardiovascular disease

1:37

that could then undergo risk factor modification

1:40

and when necessary referral to a cardiologist.

1:43

And since heart disease

1:44

and cardiovascular disease is one of the leading causes

1:47

of mortality in the us, finding it early

1:49

where risk modification can come

1:51

to play is becoming increasingly important at finding

1:55

and measuring coronary calcium is part of that strategy.

1:59

If we look at the traditional quantified AGATSTON score

2:03

that we use on a coronary calcium ct, it has strata

2:06

of coronary calcium based on the score itself.

2:10

Higher calcium scores indicate a higher relative risk

2:14

of a future cardiovascular event.

2:17

So for patients with a calcium score of zero,

2:20

asymptomatic have a very low risk of future coronary event

2:25

with two per thousand risk annually.

2:29

Whereas a patient with a score in the hundred

2:32

to 400 range is considered at moderate relative risk

2:35

for cardiovascular events,

2:36

and greater than two per hundred will have a cardiovascular

2:40

event, whereas those with a severe score

2:44

of greater than 400 known as a high

2:46

or extensive score have between two

2:49

and five chance per hundred

2:51

or 15% chance of having obstructive coronary disease lesion

2:55

of significance at the time of their coronary calcium ct.

2:59

And for these patients, we usually recommend stress echo

3:02

or stress nuclear testing,

3:03

but certainly evaluation by a cardiovascular specialist

3:06

and cardiologist is critically important

3:08

to understanding the importance in an individual patient

3:12

while going along with these individual calcium score.

3:15

Numerical strata is a visual score that you can apply on all

3:19

of your chest cts including lung cancer screening.

3:22

None correlates with a score.

3:23

Zero mild would be tiny spots of calcification.

3:28

In the TSON score range of one to two

3:31

moderate covers this broad range in between from over 10

3:34

to 400 and severe visually severe coronary

3:38

calcium is over 400.

3:40

Study of the national lung screening database has applied

3:44

this visual score against the AGAs score

3:47

and found very good correlation in patients undergoing lung

3:50

cancer screening even with the low dose,

3:53

slightly noisy image appearance.

3:56

How about findings in the thoracic aorta?

3:58

Well, aortic diameters influenced by gender, age,

4:02

and body surface area.

4:04

Unlike coronary calcium where we have nomograms

4:06

of patient age

4:08

and gender to predict what an average person of

4:11

that age might have and identify whether a person has more

4:15

or less calcification than expected by age and gender.

4:19

We don't have good lookup tables for aortic diameter.

4:23

There have been many research publications

4:25

that have identified what is considered normal

4:28

with a standard deviation around it for different parts of,

4:31

uh, parts of the aorta that we can apply,

4:33

but they're not integrated like coronary calcium score into

4:37

software that comes with the CT examination.

4:39

As we're interpreting, the definition

4:42

of an aneurysm is 150% diameter

4:45

or greater compared to what it should normally be.

4:48

So in the ACEing aorta,

4:50

five centimeters is considered an aneurysm,

4:52

and in the descending ATA it's four centimeters.

4:56

A dilated atic

4:58

or fusiform dilatation of the aorta is between normal

5:02

and that aneurysm threshold,

5:04

and it does depend on patient size.

5:08

In the ascent aorta, we generally use four centimeters

5:11

or 40 millimeters, which is about two standard deviations

5:14

above the mean diameter adjusted for age, sex,

5:17

and body surface area,

5:18

but not yet meeting the criteria for an aortic aneurysm.

5:23

The Framingham heart study a well-known study

5:26

of cardiovascular disease looked at the average diameter

5:29

of the aorta on ECG gated non-contrast multi detector cts in

5:33

nearly three and a half thousand patients,

5:36

and these are the diameters that they found in men.

5:40

The average normal diameter

5:42

of the ascending aorta was 34 millimeters

5:44

and descending 25.8 or 26 millimeters.

5:48

In women. Those theus were smaller,

5:50

32 millimeters in women in the ascending

5:53

and 23 millimeters in the descending.

5:55

So these are good normal numbers to keep in mind.

5:58

You'll notice around these average diameters are standard

6:01

deviations and those standard deviations can be quite large

6:05

of plus or minus three to three and a half millimeters.

6:08

So also keep that in mind when looking at the aorta

6:11

at 5.5 centimeters or larger.

6:13

Intervention is usually recommended

6:15

for an aortic aneurysm due to the increased risk of rupture,

6:19

and that size threshold for surgery is lower in patients

6:22

with connective tissue diseases such as Marfans

6:24

or ALOS Danlos at five centimeters.

6:27

In these patients, they may often undergo prophylactic

6:30

aortic root replacement due to abnormality at aortic root

6:33

and of aortic valve concomitantly.

6:36

The 2022 American College of Cardiology,

6:40

American Heart Association guideline for the Diagnosis

6:43

and Management of aortic disease is an excellent reference

6:46

and many organizations contributed to this guideline,

6:49

including the American College of Radiology.

6:52

This has a lot of information about various types

6:55

of thoracic aortic disease, including patients

6:58

with connective tissue disease.

7:00

It has an excellent section on how

7:02

to measure the thoracic aorta

7:04

for which we contributed the baseline images here from the

7:07

University of Michigan, and it gives you the recommended

7:10

timeframes for of aortas

7:13

of different size in different patient populations.

7:16

An important piece that I extracted from

7:18

that guideline is this graph shown at right

7:21

as aortic size increases from under 3.4 millimeters to three

7:25

and a half to almost four centimeters, to four to four

7:28

and a half centimeters, the risk

7:30

of aortic dissection increases,

7:33

and by the time an aortic diameter is seen

7:35

of 4.5 centimeters

7:37

or larger in the ascent aorta, the risk

7:40

of aortic dissection is much higher.

7:42

So it's very important that patients

7:44

who have a dilated aorta are appropriately seen

7:46

by cardiovascular specialists,

7:48

undergo echocardiography when important

7:51

and serial imaging depending on their underlying family

7:54

history and underlying risk factors for disease,

7:57

to make sure that they are aware of their risk

7:59

of aortic dissection, aware of the risk of aneurysm rupture,

8:03

and know to come in

8:04

and seek health care visits potentially

8:07

to the emergency room if they're having acute symptoms.

8:10

If we do these things,

8:11

we can help prevent the mortality associated

8:14

with thoracic disease.

8:17

The last cardiovascular dental finding I'm gonna talk about

8:20

is epicardial fat,

8:21

and people are generally

8:22

less familiar with its significance.

8:25

It's the fat that is the visceral fat depot enclosed

8:29

by the visceral pericardium.

8:31

It's the fat that surrounds the coronary arteries

8:33

and is found in the intra atrial septum.

8:36

We often call that lipoma of hypertrophy

8:38

of the atrial septum when it looks somewhat bulbous mass

8:41

like or bow tie shaped.

8:43

Several studies have shown a relationship

8:45

between increased epicardial fat

8:48

by measuring the actual volume with coronary artery disease,

8:52

with the presence and progression of coronary plaque

8:55

With major adverse cardiovascular events

8:57

or mace with myocardial ischemia

9:00

and atrial fibrillation, even after adjusting for obesity

9:04

and traditional cardiovascular risk factors.

9:07

Here are just two examples

9:08

of epicardial fat measured using density analysis.

9:13

On the left. What is shown in red is all the fat

9:17

that is considered in the epicardial component

9:20

and what is yellow extending into the mediastinum is

9:23

considered extra pericardial fat.

9:26

This information can either be hand drawn and measured,

9:30

but nowadays we have AI

9:31

and software tools that will do this calculation for you

9:34

with the radiologist's important role

9:36

of validating the information

9:38

and the measurements that are obtained.

9:40

An example on the right is a deep learning segmentation

9:43

of the epicardial adipose tissue.

9:46

Again, that is extracted

9:47

what is fat density from the volume and can measure it.

9:52

This is a area of increasing clinical research study,

9:57

but these relationships, these important relationships

9:59

with many forms of cardiovascular disease have now

10:02

been well established.

10:04

I expect someday in the future this will become a routine

10:06

measurement on chest cts.

10:08

We may not be there yet,

10:09

but this is definitely something when you see,

10:12

I usually report it in my lung cancer screening

10:14

and chest CT exams.

10:15

In general, if I see increased epicardial fat.