0:00

So imaging, uh, neuroimaging of 2023.

0:03

Still the most important technique is the structural MRI.

0:09

We cannot interpret physiologic

0:11

or any other fancier imaging technique without actually

0:15

seeing what the tumor looks like on structural imaging.

0:19

But we also do physiology based MRI to assess

0:23

where their vascularity their metabolism.

0:26

And another very important, uh, type of technique

0:30

that we use is this hybrid imaging called PET ct or PET mr.

0:34

And many institutions are beginning to use this technique

0:37

to look at is this a recurrent tumor

0:40

or is this a radiation necrosis?

0:44

So today I'm only going to highlight couple

0:46

of the structural and couple of physiologic MRI.

0:50

And as I said

0:52

before, structural MRI post con precon, T one,

0:56

T two flare multimodality multiplanar imaging.

1:00

This is the bread and butter of what we do,

1:02

and this will never go away,

1:05

but we put additional test to look

1:08

for hyper vascularity, whether there are leaky VAs, uh,

1:12

permeability and whether there is a hyper cellularity

1:16

or where there's high choline metabolism.

1:19

So physiologic, MRI gives us a lot of insight into

1:25

very non-invasive way of gland, um,

1:28

glancing at their tumor biology.

1:30

It's not as good as obviously actually looking at pathology,

1:34

but it's a really powerful non-invasive tool.

1:39

And this is what we do at UCSF

1:41

and it's pretty standard at most institution.

1:44

Pre post T one, T two FSC flare and DWI

1:48

and a D, C, uh, D uh, a DC and DW.

1:51

This is a must. And we also do, uh, SWI

1:56

and a SL profusion imaging.

1:59

SWI is becoming more

2:00

and more important in brain tumor imaging

2:03

because we use this primarily to look for areas

2:07

of blood products, especially after radiation therapy.

2:11

And we use this for assessing where the, the extent of micro

2:15

and macro hemorrhages

2:17

and also vascular lesions that are, uh,

2:19

mimicking brain tumors

2:21

and primarily in the brain tumor arena.

2:23

We use this to assess for the extent of radiotherapy, uh,

2:27

related injuries.

2:29

So here three different patients

2:31

with susceptibility weighted imaging.

2:33

You could see this patient as literally innumerable punctate

2:37

dots of susceptibility or micro hemorrhage.

2:40

This is a patient who received whole brain radiotherapy

2:44

for medulloblastoma 15 years prior.

2:48

Here's a patient with very peculiar looking branching

2:51

pattern of SWI.

2:53

This is a person with a ven neuritis.

2:57

This whole thing was removed.

2:58

Removed, and it's not glioblastoma.

3:01

This is a ven neuritis or veins that are partially thrombo.

3:06

And this is a patient with hyper, um, very clear,

3:10

large vascular mass.

3:12

And that's cavernous malformation. So SWI, very helpful.

3:16

Here's an example that we saw at tumor

3:18

where a patient had a, a re enhancing,

3:20

very aggressive looking, right brachi

3:23

and pontus mass in the posterior fossa.

3:26

But if you look at patients, SWI, there are

3:30

new innumerable punctate micro hemorrhages.

3:33

This is a telltale sign

3:35

that patient probably had a radiation therapy.

3:39

And lo and behold, we got the history

3:41

after the fact that patient had a nasopharyngeal carcinoma

3:45

and a pit tumor that were radiated twice before.

3:50

Uh, we did not have the radiation field,

3:52

but with that history

3:53

and with that SWI appearance,

3:55

we feel very comfortable calling this radiation necrosis.

3:58

And patient was treated for steroids to control some

4:01

of the edema related mass effect

4:04

and pay this lesion slowly, uh, disappeared.

4:08

DWI very important sequence.

4:11

We use this to, uh, assess work,

4:14

acute infarc abscess, cellular tumor,

4:17

and, uh, actively demyelinating lesion.

4:20

So here are three different patients.

4:22

Here's the DWI imaging without even looking

4:25

at structural imaging.

4:26

When you see this homogeneous in, uh, reduced diffusion

4:30

with an irregular mass like this,

4:33

this is a intracranial abscess until proven otherwise.

4:38

Here's a patient, you can barely make it out.

4:40

The lesion on DWI kind of disappears.

4:43

This is what diffuse glioma looks like on a diffusion.

4:48

Here's a patient with two lesions, have a leading edge,

4:52

reduced diffusion.

4:54

This is pretty classic for non neoplastic,

4:57

usually inflammatory, uh,

5:01

actively demyelinating type of lesion.

5:03

And this young, uh, patient was biopsied

5:05

and that's a tumor effective demyelinating lesion.

5:09

So diffusion is a must sequence when you're interpreting a

5:13

brain brain mass.

5:15

Here's another example.

5:16

This patient came to us

5:18

with a preoperative diagnosis from elsewhere, right?

5:21

Frontal glioblastoma. I think that's not a bad diagnosis.

5:25

There's a lots of mass effect.

5:27

There's edema crossing the corpus callosum

5:30

with central necrosis ri of enhancement.

5:33

But once you see the DWI

5:35

and a DC, you know that there's

5:38

homogeneous reduced diffusion within the necrotic tumor.

5:41

So that is a very unusual appearance of a glioblastoma.

5:45

So this is more classic appearance for biogenic abscess.

5:50

And indeed pathology proved that this is biogenic abscess.

5:54

Our surgeons going in knew

5:56

That this was going to be a puss 'cause we told them

6:00

and they end up just doing a little bur hole

6:02

and sucking that pus out.

6:04

And patient did great.

6:06

Here's a young woman that I showed a little bit earlier.

6:09

This, uh, young woman was diagnosed with stroke at an

6:12

outside hospital and you could see why, why?

6:15

Because there is actual homogeneously reduced diffusion

6:20

and it's very dark on a DC,

6:22

but I think most of you would also notice that

6:25

that shape is not a good, good, uh, shape

6:28

for a territorial infarct.

6:30

But nonetheless, patient was fine.

6:33

The workup was negative, was transferred to our hospital

6:36

and patient underwent surgery.

6:38

And this is ahy hypercellular,

6:41

unfortunately what's called a molecular

6:44

glioblastoma perfusion.

6:47

We use it to look for hyper vascularity

6:49

hypervascular tumors.

6:51

We also use perfusion for, to detect recurrent tumor

6:55

assessed for glioma grade and sometimes postictal changes.

7:00

Here's a patient who came to us

7:02

with a homogeneously enhancing right cerebellar mass.

7:07

And you could see that DWI is not reduced.

7:10

There's a little bit of a rim

7:12

of susceptibility, but not much else.

7:15

So the question is, is this a metastasis or something else?

7:18

Patient did undergo whole body workup and there was no mass.

7:22

And if you add a SL perfusion, you could see

7:26

that the whole lesion is very, very vascular

7:30

in the cerebellum.

7:31

And this is pretty classic appearance for

7:34

a heman neoblastoma.

7:36

And that's indeed what it was on pathology.

7:40

Here's a person who's been coming to us for, um,

7:43

serial imaging after patient had a subtotal resection.

7:48

But you could see here that we don't know

7:50

where the recurrent tumor here is.

7:52

Patient had a seizure, they controlled the seizure.

7:55

So after they controlled the seizure,

7:57

we brought the patient back and did a profusion imaging

8:01

and you could see that there is a clear unmistakable lump

8:04

of hyper vascularity associated with

8:08

non mass like flare here.

8:10

So our neurosurgical colleagues went in

8:13

and resected this, uh, hyperperfusion area.

8:16

And the whole thing was a live recurrent diffuse glioma,

8:21

IDH wild type spectroscopy.

8:24

We use this tool now as a problem solving tool.

8:27

Here is a normal single voxel spectroscopy, normal

8:32

NAA creatine and colon.

8:35

This is what you wanna see.

8:39

And we've done many, many spectroscopy studies,

8:43

both two DA single voxel, 2D and 3D.

8:47

But I still find this single voxel very powerful.

8:50

And here's an example of some of our patients, um,

8:54

that we did on spectroscopy.

8:55

Oh, by the way, a single voxel only requires about less than

8:59

three minute of imaging.

9:01

So it's a really powerful tool

9:03

that does not take up much in terms of additional imaging.

9:07

And we've now kind of developed four different types of

9:12

spectroscopic appearance of an abnormal lesion.

9:15

So what we call the proliferative, where there's high,

9:18

high choline hypoxic profile where there is clear lactate,

9:23

peak infectious profile where we see amino acids, alanine

9:27

and acetate, and the necrotic pattern

9:30

where we see predominantly very high lipid and lactate.

9:36

And here's an example of how we use this single voxel

9:40

two minute of additional imaging.

9:41

So this patient came to us with a left frontal glioblastoma

9:46

as the preoperative diagnosis

9:48

does look like glioblastoma was central necrosis.

9:52

But once you get DWI, you know that inside of

9:55

that reen enhancing lesion,

9:57

there is a clear reduced diffusion that looks like pus.

10:01

So we brought the patient down

10:03

and with a single voxel spectroscopy using te

10:07

of 35 milliseconds and 2 88 milliseconds,

10:11

and we saw all the metabolites

10:14

that classically seen in biogenic abscess such

10:17

as amino acid, lactate acetate,

10:22

and the choline, which is not a tumor marker, it's a, uh,

10:27

membrane turnover marker is very, very low.

10:29

So our confidence putting the together with the diffusion

10:33

that this is going to be a genic abscess was near 100%.

10:37

And our neurosurgical colleagues just did a very small bur

10:41

hole and sucked out the fluid.

10:44

And lo and behold, there is that yellowish purine material

10:49

and this is a path proven biogenic abscess.

10:53

So let me now, uh,

10:55

focus more on the brain tumors based on the molecular

10:58

genetics, and I'm going to start with three different types

11:01

of pediatric tumors

11:03

and go on to adult tumors using the, uh, imaging techniques

11:08

that I just described to you.

11:11

So pediatric brain tumors in the WHO scheme from 2016

11:16

to 2021, many different, um,

11:19

classification changes have been made.

11:21

The first is these two tumor types,

11:25

one medulloblastoma, the other appendamoma,

11:29

and you could see that without

11:31

knowing anything about the tumor.

11:32

So here's post con T one.

11:34

You could see that the, this patient has a tumor

11:37

that is relatively homogeneously reduced and diffusion.

11:41

So this is going to be some type

11:43

of a cellular tumor patient.

11:46

On the other hand, this tumor both are

11:48

midline enhancing lesion.

11:50

You could see that DWI is not

11:52

Reduced.

11:53

So DWI is single most helpful sequence

11:57

after looking at post contrast imaging.

12:00

So we already know this patient has a hypervascular,

12:04

a hypercellular tumor, and that's a me neuroblastoma.

12:07

And this patient on the right, this is a patient

12:11

with APPENDAMOMA

12:13

and DWI is really the first step towards

12:18

honing down into the molecular

12:20

or biologic feature of their tumors.