0:00

So here the take-home points from the session

0:03

on CT perfusion, I'd say number one

0:06

use non-con CT to guide your interpretation

0:09

of infarct core. The use

0:12

of CTP. CBF Maps is most helpful as

0:15

an adjunct for estimating the infarct core

0:18

in the late window of hyperacusro. That's

0:21

like 6 to 24 hours. I'm outside this

0:24

window. It's a little bit less reliable in the early window beware of

0:27

ghost infarct core that

0:30

is overestimation of what is actually infarcted based

0:33

on your CBF map that on follow-up turnout

0:36

not to be infarcted.

0:38

Beware of false negative situations that

0:41

can occur very late in acute stroke

0:44

into the Subacute window because that territory

0:47

has already reperfused. So you have normalization or

0:50

even high per perfusion on your

0:53

cvf and and TMax Maps similarly

0:57

beware of bilateral perfusion

1:00

deficit which may mess up the computers

1:03

analysis of what is abnormally reduced

1:06

relatives removable blood volume. So you have to rely on

1:09

your quality of analysis. Okay. This territory is normal. This one

1:12

is abnormal on the ipsilateral side as well.

1:16

Beware of stroke mimics like seizure that

1:19

can be occurring the case of press and several Venus

1:22

thrombosis as we saw in our two cases

1:25

use CTP as a helpful guide to

1:28

augment your review of CT angiography, especially for

1:31

challenging areas, like medium vessel occlusions stenosis

1:34

or in our

1:37

last case Venus thrombosis, which can be easily missed

1:40

on a CT angiogram as well. There are

1:43

emerging uses for CTP for crowded stenosis like

1:46

your case of near occlusion that we had as well as

1:49

for cerebral basis fathom after Hemorrhage about

1:52

caution you to interpret these not in the

1:55

same way that you interpret Lara's vessel occlusions Strokes, right the interpretation

1:58

about the threshold the CBF less than 30 team experience

2:01

doesn't really apply. It's not been validated in

2:04

these clinical contexts. So I would stick to remaining descriptive

2:07

about there these areas of hypo perfusion

2:10

corresponding to the CT angr and Geographic

2:13

and normalities and hopefully

2:16

That's helpful additional data point for the managing neurologists

2:19

neuro-interventional Specialists

2:22

to take to into

2:25

account when determining how to manage these very

2:28

complex patients. So with that having to

2:31

take any questions about the talking general

2:34

or this very last case.

2:36

TTP or TMax which is preferred. Is it

2:39

okay to evaluate only with TTP since some vendors don't

2:42

provide TMax and only give MTT and TTP.

2:49

There's certainly disagreement in the literature about what is

2:52

the best parameter to use the TTP and

2:55

TMax for relatively similar metrics and

2:58

just so happens that the dominant vendors

3:02

at least around my neck of the woods use

3:05

TMax primarily in determining what

3:08

is called the critical hyper

3:11

hypo perfusion Zone, but I

3:14

certainly understand that, you know, the the literature

3:17

is not 100% clear that team expert in

3:20

the six seconds is the best whatsoever in that some

3:23

vendors may choose to use TTP as well. But I

3:26

am agnostic about that. I think there's

3:29

there's

3:32

kind of a general

3:35

preference among these vendors to use team acts and

3:38

that's what I stick to and that's what I'm familiar with.

3:41

Should we always report the hypodensity volume?

3:46

I think that's a stylistic thing. I like

3:49

to do that just because I like to communicate a

3:53

somehow the

3:56

size of infarx and that's

3:59

based on my experience

4:02

of seeing reports that say there's a

4:05

MCA territory infarc, but the infarct is actually like, you know,

4:08

just the basal ganglia plus the insula and just like, you know 10 milliliters

4:11

in Fargo. That's a very different story or the

4:14

patient compared to an MCA in Fargo. That's

4:17

200 milliliters. Right? And so just because

4:20

I like thinking quantitatively I try to estimate the

4:23

area of infarct some people like doing it kind

4:26

of semi quantity large medium small would have you

4:29

but I I if it's easy

4:32

to measure and just takes me a couple seconds once I'm

4:35

fast out with the measuring tools my packs I

4:39

Try to estimate the infarct volume.

4:42

Usually here because we get MRI

4:45

and everybody I usually just provide it

4:48

for volume on the MRI that it's a better a more

4:53

reliable way to measure it than trying to estimate it

4:56

on the first non-con has CT but in

4:59

general, you know, I think there is some relevance

5:03

providing a volume measurement at some

5:06

point because that is correlated with

5:09

their neurologic prognosis.

5:12

Should we exclude a total region on the

5:15

aspect score even if a small part is involved?

5:21

Strictly speaking how the aspects score was defined.

5:24

Yes, if only

5:28

one part of say the

5:31

m6 section of the super ganglionic,

5:34

you know parietal cortex was

5:37

infarcted. Yes, you would say that

5:40

region is affected. It doesn't have to be the whole region is affected.

5:44

Now I want to be clear that to count as affected you

5:47

have to have great white differentiation loss. It's not

5:50

enough to have subtle effacement. It's not enough to

5:53

have a white matter alone hypodensity. Even if

5:56

that's why matter if are you just don't know on non-continent CT

5:59

so you have to see great white differentiation laws

6:02

somewhere in that region to say

6:06

that's affected. But yes any small part

6:09

of that region effective means that the region is affected. So people

6:12

have criticized to aspects score. It's not linearly scaled

6:17

to the infer volume, but this is

6:21

a relatively quick and easy way

6:24

to express the extent of

6:27

MCA territory involved in

6:30

Far That neurologist and neuro

6:33

interventionalists are familiar with