0:00

Screening for lung cancer

0:02

with low dose CT is a public health test applied

0:05

to a large swath of the population at high risk

0:07

for lung cancer by virtue of age, combined

0:10

with their history of cigarette smoking.

0:13

There are many other things we can find on a lung cancer

0:15

screening disease CT that are essentially screening.

0:19

We can screen for bone mineral density.

0:22

We can screen for coronary art calcification, things that

0:25

by identifying we have disease mitigating strategies

0:28

that can reduce morbidity and mortality.

0:31

So let's look at bone mineral density.

0:34

We're gonna talk about the importance

0:36

of bone mineral density and compression fractures.

0:39

Measuring bone mineral density

0:41

in a straightforward way on your lung cancer screening cts,

0:45

and looking at the ranges of bone mineral density

0:48

that are considered normal osteopenia and osteoporosis.

0:53

Well, why is bone mineral density important?

0:56

Patients with a heavy cigarette smoking history have an

0:59

increased risk of osteoporosis.

1:01

Treatment of osteoporosis reduces the associated morbidity

1:05

and mortality for patients with lung disease.

1:08

In particular, compression fractures increase their risk

1:11

of pneumonia and pneumonia related admissions and mortality.

1:16

If you think about it, when a patient has compression

1:19

fractures, particularly when they're acute to subacute,

1:21

they often have pain.

1:23

That pain prevents them from taking in great big breasts

1:27

like they normally would.

1:29

So they're taking relatively shallow inspirations

1:31

because their lungs are abnormal.

1:33

Perhaps because they have emphysema

1:35

or other forms of COPD, they're already at an increased risk

1:39

of infection and now they're not essentially taking great

1:42

breaths in and out, so they're essentially

1:44

splinting their lungs.

1:45

They're more likely to get pneumonia.

1:47

When they get pneumonia. They're more likely

1:49

to get hospitalized,

1:50

and that's more likely to be associated

1:52

with pneumonia related mortality and morbidity.

1:55

So if we can identify bone mineral density upfront,

1:59

we can treat, we can prevent compression fractures

2:02

and we can reduce morbidity

2:04

and mortality for these patients.

2:06

Studies of lung cancer screening series have reported up

2:11

to a third to half

2:12

of patients having vertebral body fractures.

2:15

I think that's a very high estimate

2:18

and is a very high risk burden population.

2:21

While osteoporosis and osteopenia are very common,

2:24

and I would think that occurs in about a third of patients

2:27

that we see for lung cancer screening,

2:29

I don't think impression fractures occur

2:31

as often has been reported in some

2:34

of the selected publications in the literature.

2:37

Vertebral body fractures

2:38

and low bone mineral density are both associated

2:41

with a doubling of risk adjusted hazard ratios

2:44

for all cause mortality independent of other risk factors.

2:48

In other words, identifying abnormal bone mineral density is

2:51

important to avoid morbidity and mortality.

2:55

If we look at the ACRs incidental findings,

2:58

quick reference guide, it has a section on musculoskeletal

3:01

findings specifically for bone mineral density.

3:04

The recommendation is that for 130 household unit density

3:09

and higher as measured at the L one vertebral body,

3:13

assuming a relatively normal L one vertebral body, that

3:16

that's considered normal bone mineral density.

3:19

If the house unit density

3:20

of L one is under a hundred ounce units,

3:23

that's considered osteoporosis for which referral

3:26

by the pulmonary care physician

3:28

and consideration of DEXASCAN is

3:30

an appropriate recommendation.

3:32

And between those two categories, a hundred to 130,

3:36

it's considered the range for osteopenia

3:39

and consider evaluation at the PCP level.

3:41

The patient may have other risk factors

3:44

for abnormal bone mineral density

3:46

and they may want to pursue this with a DEXA scan

3:48

or to follow it as they'll get measurements on their annual

3:51

screening cts.

3:53

How are these measurements determined with these thresholds

3:56

of 130 and a hundred?

3:59

These come from comparison studies that have looked at

4:02

DEXA in patients who've undergone CT scans

4:06

and correlating a DEXA findings of osteoporosis

4:09

and osteopenia with the hounds full unit measurements in the

4:12

L one vertebral body.

4:14

Since the L one vertebral body is used

4:17

as a marker on DEXA scans for determination of osteopenia

4:20

and osteoporosis.

4:22

As a radiologist, when I look at a chest ct,

4:25

we commonly have the L one vertebral body,

4:28

and so I'll put an RL one on the L one vertebral body

4:32

to measure bone mineral density.

4:34

This can also certainly be done by automated tools

4:37

that can be implemented similar

4:39

to other artificial intelligence tools

4:41

to find the L one vertebral body and make that measurement.

4:44

If L one is abnormal, move the T 12

4:47

and if you don't see L one,

4:49

you can use the T 12 vertebral body instead.

4:53

This is my standard layout for starting place

4:56

of interpreting a lung cancer screening ct.

4:58

Again with my axial MIPS

5:00

and lung windows, soft tissue and bone windows.

5:03

My CT scout as an important way, like a mini chest x-ray

5:06

to look at the chest, my coronal

5:09

and sagal images, which are nicely displaying the vertebral

5:12

body heights and then my quantitative tool

5:15

for emphysema assessment and lung volume.

5:17

I can see that the vertebral bodies are

5:20

well preserved in height.

5:21

I don't see any compression deformities

5:23

and I can take a cursor, make it our region

5:26

of interest on the L one vertebral body

5:28

and get a measurement so that I can categorize this

5:31

as either normal osteopenia or osteoporosis.

5:35

In this case, the bone mineral density came out at well

5:38

above 130 household units

5:40

and represents normal bone mineral density.

5:43

I tell people that you generally shouldn't guess

5:45

what the bone mineral density is.

5:47

You should put an ROI on it.

5:49

Depending on the other tissues,

5:51

depending whether you've given contrast,

5:53

depending on whether there are

5:55

compression fractures and adjacent

5:57

Or even the bone or soft tissue window settings you're

6:00

using, it can sometimes make the bones look higher

6:02

or lower density than an actual density measure is.

6:06

So it's not that hard

6:07

to take an ROI put it on the L one vertebral body in either

6:10

the sagal coronal plane

6:12

and make that measurement to determine if it's normal

6:16

osteoporosis or osteopenia.