August 1, 2023 • 17 mins
We are beginning season two with a 3 part “The doctor is In” Series going over questions with Dr. Stuart Fraser, the director of the pediatric stroke program with McGovern Medical School at UTHealth Houston. This month’s Part one episode focuses on medical terms parents read on radiology reports and goes into more detail about the different radiology tests doctor’s order as well as the major blood vessels of the brain. Each episode for this season will end with a focus on a special children’s book with a "Things to Think About” takeaway lesson. This month's book is "Maybe" by Kobi Yamada.
Guest Website Link
Webpage: https://www.avmalliance.org
Go Fund Me: https://www.gofundme.com/f/avmalliance
Our FB Page: https://www.facebook.com/AVMAlliance
Our FB Group: https://www.facebook.com/groups/325321586185434
Instagram: https://www.instagram.com/avmalliance/
TikTok: https://www.tiktok.com/@avmalliance
YouTube: https://www.youtube.com/@avmalliance
Personal Blog: https://www.caringbridge.org/visit/kylerlewis
Twitter: https://twitter.com/avmawareness
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Raylene Lewis (00:02):
Hi there, and thank you for joining us on AVM
Alliance, a pediatric podcastfor families and friends whose
lives have been affected bytraumatic brain injury, rare
disease, brain disorders, orstroke.
The purpose of this podcast isto focus on the kid side of
brain injury with honest talknews, information, and
discussion for our community.
(00:24):
Being a parent of a medicallycomplex child is an extremely
difficult path to suddenly findyourself on.
I'm Raylene Lewis and my sonKyler suffered a hemorrhagic
stroke at age 15.
Thank you for joining us.
We are beginning our season witha three part: the Doctor is In
series going over questions witha medical professional that
(00:46):
parents have submitted to thispodcast.
This month's part one episode,will focus on the different
radiology tests doctor's orderNext month's Part two episode
will continue the discussions onmedical terms parents read on
radiology reports, and alsowe'll go into more detail about
the epilepsy and EEGs, as wellas stroke in infants with part
(01:09):
three, looking into questionsabout stem cells and other
therapies and programs for kidswho have suffered a stroke.
Each episode for this seasonwill end with a focus on a
special children's book with thethings to think about, takeaway,
and don't forget, we now have asupport group that meets monthly
over Zoom, and we would trulylove to have you join us.
(01:32):
With me today.
I have the Director of thePediatric Stroke Program with
the McGovern Medical School atUT Health Houston, Dr.
Stuart Fraser.
Dr.
Fraser thank you for joining us.
Dr. Stuart Fraser (01:43):
Thanks for having me.
I really appreciate the invite.
Raylene Lewis (01:46):
Oh, well we are just so excited.
We know your time is very, veryvaluable.
I have a list of questionspeople had asked us to start
off.
Now we have access to thereports and all the tests and
scans that are done.
And that leads me to a couple ofjust I guess, general medical
school questions to start offwith, if you don't mind.
(02:08):
Okay.
Those are fun.
I'm happy to.
One of the biggest things Ithink that parents look at is
they wanna know the results ofthe scans and they wanna know
what that means.
But it's really hard to tellwithout Google right next to us.
So really quick, can you explainthe differences in the words on
what we see between what is M CA P C A A C A?
Dr. Stuart Fraser (02:30):
Wow.
Yes.
I, I would be happy to, that isa second or third semester of
med school.
Question once, once you get tothose, so what you're talking
about are different arteriesthat are in the brain.
So there are two big groups ofarteries that go to your brain.
Hopefully you're not watchingviolent movies, but if you are,
(02:51):
you'll, you'll know about theones on the front that you can
feel with your two hands.
Those are the carotid, and thatsupplies, we call that the
anterior circulation.
It supplies most of the front ofyour brain, and then in the back
you can't feel it.
You have the basilar artery andthat supplies your brainstem.
A lot of the back half of yourbrain, stuff that controls like
(03:12):
vision and breathing andcoordination.
Those acronyms, people like use,talk about branches of those
different big arteries.
So the biggest, probably mostimportant branch of your
internal carotid artery, it's.
The most common one that peopleget strokes in is the M C A, the
middle cerebral artery.
And not surprisingly, if youlook at a cross section of the
(03:34):
brain, it supplies the middlepart.
The a c A is the anteriorcerebral artery, and the P c A
is the posterior cerebral arterythat comes from the the back
that we talked about.
Raylene Lewis (03:44):
So the, the a c a is the front.
Dr. Stuart Fraser (03:46):
I'm greatly oversimplifying it, but yes,
it's more front and in themiddle.
I think thinking of a anterioris front, middle is middle, and
posterior is back.
Would be a pretty good way tothink about it.
The brain can be a littlecounterintuitive, so when you
look at the maps of what thoseterritories are, they get sort
of wonky.
But yeah, that's a good way tothink about it.
I think.
Raylene Lewis (04:06):
Okay.
And then talking about just acouple things that people show
up with on diagnosis, can youjust very briefly explain a V M
and the difference between thatand a v m fistula and then VO GM
and then C P A?
Dr. Stuart Fraser (04:21):
Yeah, sure, sure.
And arteriovenous malformationis the most common cause of
hemorrhagic stroke in kids.
So a bleed in the brain,probably this happens.
Before birth, or maybe shortlyafterwards, the arteries, which
take very fast flowing blood,connect to veins which carry
blood back to your heart wherethey're not supposed to.
(04:42):
They're supposed to becapillaries in the middle.
If they connect incorrectly,they, they tend to have
something in the middle calledinus.
And those nidus tend to befragile and they can get bigger
over time and they can rupture,and that's when you run into
really big problems.
Arterio venous fistulas.
Often come from a trauma.
There's some sort of injury thathappens that will connect
(05:05):
arteries and veins.
It's not something you're bornwith a lot of the times, but it
can be.
And those tend to have very highflow blood so high that it can
take blood flow away from areasthat it needs to go and that can
cause really bad symptoms thateffect.
Yeah, we see those in traumapatients or, or patients after
a, a trauma to the facesometimes.
(05:26):
Usually those are treated bysurgeons.
And the vein of Galenmalformation is usually
something that you're born with.
The big issue is that there's.
A connection again between anartery and a big vein at the
center of your brain that leadsthat vein to get bigger and
bigger and bigger.
And it can cause all sorts ofproblems after you're born.
We usually watch those patientsvery, very closely'cause we're
(05:49):
trying to let them grow and getstronger before we treat it.
But if they start developingmajor symptoms, we, we have to
treat it earlier.
And a few people have startedtrying to treat them even before
Raylene Lewis (05:58):
birth.
Are the VMs the one where youtend to also see heart issues
the
Dr. Stuart Fraser (06:03):
most?
Yeah, so that's how babies willpresent classically.
And you or me our brain is.
Not that big compared to therest of our body.
I mean, it's big compared tomost other mammals, but it's,
it's not that big.
The majority of our blood flowis not going straight up to our
brain in a baby.
A lot of the blood flow is goingstraight to their brain.
(06:24):
So if you have this system whereblood is just going straight
from the artery to the vein andnot slowing down, the heart is
trying to perfuse the brain andthe blood is just bypassing it
so the heart beats harder andharder and harder until it goes
into what we call high outputheart failure.
Oh wow.
In my experience, and if youlook at some of the medical
literature out there, a lot ofthose kids have more
(06:46):
difficulties with school andlanguage later in life than I
think we would think becausethey look so great when they're
babies.
And it's important to rememberthat if you ever have brain
vessel disease, you might end uphaving some issues that you
didn't expect.
And we should always be watchfuland try to help if they do pop
up.
Raylene Lewis (07:04):
Super important because that's that's a problem.
I know, you know, my son Kylerhas been recovering.
He has a AVM that started out asa five, and a lot of people
don't realize that there'sanything wrong because he looks
completely normal and healthy onthe outside.
Yeah.
Now what about that C P
Dr. Stuart Fraser (07:21):
a Oh, cerebral per proliferative
angiopathy.
Okay.
Those are often confused withAVMs.
To be honest, I, I haven't had apatient who's had a cerebral
proliferative angiopathy thatwe've had to treat.
I will say there are a lot ofdifferent.
Brain vessel diseases out therethat we don't entirely
(07:42):
understand yet.
And this c p A is one where theytend to be bigger.
There's normal brain in between,and the treatment options are
different.
Raylene Lewis (07:51):
Okay.
Yeah, that's right.
Very, very diffuse as comparedto that compactus.
Yeah.
That we were talking aboutearlier.
Here's the next question, sorry.
Still going on and talking aboutkind of the, the MRIs and things
that, that parents read ingeneral.
First question was kind of likea granola type question.
How worried do parents have tobe about the tracer materials
that's found, like in a, in anmr i?
(08:13):
Because you know that an M R Idoes not use the same it's
different technology, so it's incontrast, right?
Versus a ct, which is like aradiation.
Dr. Stuart Fraser (08:23):
Okay, great question.
So if we're talking about theradiation that you receive, CAT
scans use x-ray radiation or thesame type of radiations as that
x-rays.
Have those can, if you getenough of it cause problems like
increased risk of cancer downthe road.
In extreme cases, you couldstart having cell injury, but
(08:45):
you'd have to get scan afterscan, after scan after scan for
a long, long time.
Generally.
The amount that is in a CAT scanis pretty safe.
We like to say it depends on theCAT scanner, but a lot of times
the amount of backgroundradiation you're getting in one
CAT scan is the equivalent tosay, a back a year of background
radiation of just walking aroundif you lived in any city in the
(09:07):
us something like that.
Radiation over time does causechanges in D N A, which can
cause cancer.
20, 30 years down the line.
We try to avoid CAT scans inchildren for this reason when we
can generally the amount of riskof direct harm from a CAT scan
is pretty low.
And then Mr.
(09:27):
Mri, as far as we know, thatjust uses magnets to try to take
pictures of the brain and body.
And as far as we can tell,they're absolutely no harmful
effects to to MRIs and humansare animals in which they've
been
Raylene Lewis (09:38):
tested on.
What about the contrast?
Because I know you do MRIs withand without, and the, with the
contrast shows like lesions, butthen you're injecting something.
Yeah.
Yeah.
What?
That's right.
So
Dr. Stuart Fraser (09:48):
whatcha injecting?
So the contrast goes so in Ct Ain cts, it's usually iodine
contrast that iodinated contrastwill make blood vessels light
up.
Because the contrast stays inblood vessels, but it will also
go to places that have lots ofblood going to them.
So sometimes they can help ussee abscesses or cancers.
(10:10):
Mostly what we use contrast forwith CAT scans are to take
really detailed pictures ofblood vessels.
We can't see them really withoutthem unless something's very
wrong.
Really, the only risk from theiodine is if you get too much of
it, it can cause kidney injury.
Your kidneys metabolize it.
And spit it out.
So for you or me, we get one,it, it really doesn't matter.
(10:31):
If you were to get them over andover and over again, this is why
we sometimes like to wait beforewe keep doing repeat ones.
Eventually it could cause kidneyinjury if you ever were to get
so much that your kidneys getoverwhelmed, extremely rare for
that to happen.
We do it in patients even withreally bad kidney disease if we
have to.
But it is, it is worthmentioning.
(10:51):
I've never actually had a caseof contrast induced kidney
damage, but we always talk aboutit.
Sure.
And then for MRIs we use GaddGAD contrast it's called, which
has the same purpose.
It lights up blood vessels andtumors, but in a way that the M
r I can detect it.
'cause M R MRI can't reallydetect the iodine.
And same issue it has to gothrough your kidneys when we're
finished with it.
(11:12):
In a young, healthy person,you're really not gonna notice,
but you do have to be carefulabout giving too much.
And there are some extremelyrare side effects that have been
reported in the literature thatagain, I haven't seen, but
they're, they're reported
Raylene Lewis (11:24):
for the most part, though, with both of these
types of contrast, it shouldflush out at the end, right.
Dr. Stuart Fraser (11:29):
You, you pee it out, you got it right.
That's the idea.
So you know, if you work out toohard, you might become really
sore'cause your body'soverwhelmed.
I kind of think of the liver andkidney as the same way as low
levels of toxins they can dealwith, with no lasting damage.
You just don't wanna do too muchtoo fast.
And in fact, even when thesurgeons or interventionalists
(11:51):
are doing angiograms with acatheter, they have calculations
they have to follow about howmuch contrast they're able to
ingest.
Raylene Lewis (11:58):
Okay.
Everybody knows what an x-rayis, right?
It's for bones.
Yeah.
A, a CT is kind of somethingthat helps you look at, at
fleshy tissue.
What's the difference betweenthe C T A and the M R A and what
people are looking for, likewith Okay,
Dr. Stuart Fraser (12:12):
good, good question.
Yeah.
It, they, they differ in the waythat they take images.
CAT scans are based on x-rays.
They shoot x-rays throughsomething, however much signal
goes through tells you how densewhatever it was passing through
was.
The cat scans are just a fancyx-ray that does it a million
times and makes that that threeD picture.
MRIs use a different techniqueto look at.
(12:35):
Theoretically the same thing.
So with the CAT scan, you'reshooting x-rays through and
hoping the iodine, which blocksa lot of radiation, will cause
the blood vessels to light up.
With an M r A, they use thesetimed pulse sequences.
They're taking a measure of howlong it takes hydrogen molecules
to switch after you send amagnetic pulse through them.
(12:56):
The computer can then do somecalculations to see areas where
they think there's water movingvery fast, and areas where water
is moving fast would be yourblood vessels, and that's what
creates the picture that we seewith MRIs.
Raylene Lewis (13:08):
So an MRI is kind of more detailed on just looking
at the blood vessels themselves.
Dr. Stuart Fraser (13:13):
That's actually a good question.
So, believe it or not,generally, not really.
As in more detail that, that, sothe m r A is a specific sequence
that only looks at the bloodvessels.
A C T A will look at bloodvessels specifically, but it
also sees the rest of the, thebrain RAs a lot of the times.
And, and it really depends onthe scanner you're using.
(13:34):
They can have trouble seeingsome of the things that we can
see on CAT scans.
But they also don't have anyradiation and usually we don't
have to use contrast for themeither.
And that's why I like to getthem especially in someone who a
lot of kids with strokes aregetting scanned over and over
again.
So we're thinking 20, 30 yearsdown the line, we'd like to
avoid the radiation.
Raylene Lewis (13:55):
Okay, so here's kind of a fun side note question
on that.
Right.
Okay.
So there is the good thingcalled security at the airport,
right?
Yeah.
And it's security at theairport.
They have these scanners.
And I know that scanners havecome a long way, but as a parent
of a kid who's already beenexposed a lot of times, should
we opt for the
Dr. Stuart Fraser (14:14):
pat down?
That is a good question.
The metal detectors, I don'tthink you have to worry about
lest I heard, and then those.
Those hands up one that theyhave.
Yeah.
The, the last I heard about thatthey're using non-ionizing
radiation and so it, itshouldn't increase your risk of,
of cancer.
Think you're okay to just not betouched.
(14:35):
And you can go like this andhands up.
Yeah, hands up.
We're here to party
Raylene Lewis (14:39):
Paul.
Right.
And we will look.
Forward to next month's episodewhere we continue our discussion
with the Director of thePediatric Stroke Program with
the McGovern Medical School atUT Health Houston, Dr.
Stewart Frazier, as he explainsa lot of the words we read on
the radiology reports, as wellas the squiggles parents see on
(15:00):
an e E G.
The doctor will also answerepilepsy questions, questions
about stroke in infants, andeven a few on stroke, and the C
Ovid 19 virus.
I hope you'll join us as wecontinue this discussion next
month.
The focus of this month's thanksto think about is based on the
(15:22):
Children's book, maybe aNautilus Award winner by Kobe
Yamada.
This book beautifully tells thestory that no matter our
circumstances or background,there is endless potential in
each one of us.
It is easy to wonder why.
Why am I here?
Why did this happen to me or tomy child?
(15:43):
To my life, but it can be hardto remember that you are the
only you there will ever be, andthat each one of us has
something very special to offer.
Even though our journey may beextremely hard with times where
we can only focus on the nextright thing, it is only when you
go on a journey that discoveriesare made on your path.
(16:07):
A time will come where you areThere.
To help in a way that only youcan, maybe it will be to help
others see the beauty in a day,shine a light into places that
have been dark for far too long,or speak up for those who cannot
speak for themselves.
Or maybe it will be somethingelse completely.
(16:29):
And although there will bestruggles and fears, And even
failure.
This world needs each one of usand the unique gifts that only
we can offer to those around us.
Thank you Kobe, for thisvaluable and important lesson.
And as always, if you havequestions or have a topic you
would like to hear about, don'tbe shy.
(16:51):
Share it in the comments and letus know.
And if you liked what you heardtoday, please go online and rate
this podcast.
Remember, you're never walkingthis journey alone.
Take care.
Hi there, and thank you for joining us on AVM
Alliance, a pediatric podcastfor families and friends whose
lives have been affected bytraumatic brain injury, rare
disease, brain disorders, orstroke.
The purpose of this podcast isto focus on the kid side of
brain injury with honest talknews, information, and
discussion for our community.
(00:24):
Being a parent of a medicallycomplex child is an extremely
difficult path to suddenly findyourself on.
I'm Raylene Lewis and my sonKyler suffered a hemorrhagic
stroke at age 15.
Thank you for joining us.
We are beginning our season witha three part: the Doctor is In
series going over questions witha medical professional that
(00:46):
parents have submitted to thispodcast.
This month's part one episode,will focus on the different
radiology tests doctor's orderNext month's Part two episode
will continue the discussions onmedical terms parents read on
radiology reports, and alsowe'll go into more detail about
the epilepsy and EEGs, as wellas stroke in infants with part
(01:09):
three, looking into questionsabout stem cells and other
therapies and programs for kidswho have suffered a stroke.
Each episode for this seasonwill end with a focus on a
special children's book with thethings to think about, takeaway,
and don't forget, we now have asupport group that meets monthly
over Zoom, and we would trulylove to have you join us.
(01:32):
With me today.
I have the Director of thePediatric Stroke Program with
the McGovern Medical School atUT Health Houston, Dr.
Stuart Fraser.
Dr.
Fraser thank you for joining us.
Dr. Stuart Fraser (01:43):
Thanks for having me.
I really appreciate the invite.
Raylene Lewis (01:46):
Oh, well we are just so excited.
We know your time is very, veryvaluable.
I have a list of questionspeople had asked us to start
off.
Now we have access to thereports and all the tests and
scans that are done.
And that leads me to a couple ofjust I guess, general medical
school questions to start offwith, if you don't mind.
(02:08):
Okay.
Those are fun.
I'm happy to.
One of the biggest things Ithink that parents look at is
they wanna know the results ofthe scans and they wanna know
what that means.
But it's really hard to tellwithout Google right next to us.
So really quick, can you explainthe differences in the words on
what we see between what is M CA P C A A C A?
Dr. Stuart Fraser (02:30):
Wow.
Yes.
I, I would be happy to, that isa second or third semester of
med school.
Question once, once you get tothose, so what you're talking
about are different arteriesthat are in the brain.
So there are two big groups ofarteries that go to your brain.
Hopefully you're not watchingviolent movies, but if you are,
(02:51):
you'll, you'll know about theones on the front that you can
feel with your two hands.
Those are the carotid, and thatsupplies, we call that the
anterior circulation.
It supplies most of the front ofyour brain, and then in the back
you can't feel it.
You have the basilar artery andthat supplies your brainstem.
A lot of the back half of yourbrain, stuff that controls like
(03:12):
vision and breathing andcoordination.
Those acronyms, people like use,talk about branches of those
different big arteries.
So the biggest, probably mostimportant branch of your
internal carotid artery, it's.
The most common one that peopleget strokes in is the M C A, the
middle cerebral artery.
And not surprisingly, if youlook at a cross section of the
(03:34):
brain, it supplies the middlepart.
The a c A is the anteriorcerebral artery, and the P c A
is the posterior cerebral arterythat comes from the the back
that we talked about.
Raylene Lewis (03:44):
So the, the a c a is the front.
Dr. Stuart Fraser (03:46):
I'm greatly oversimplifying it, but yes,
it's more front and in themiddle.
I think thinking of a anterioris front, middle is middle, and
posterior is back.
Would be a pretty good way tothink about it.
The brain can be a littlecounterintuitive, so when you
look at the maps of what thoseterritories are, they get sort
of wonky.
But yeah, that's a good way tothink about it.
I think.
Raylene Lewis (04:06):
Okay.
And then talking about just acouple things that people show
up with on diagnosis, can youjust very briefly explain a V M
and the difference between thatand a v m fistula and then VO GM
and then C P A?
Dr. Stuart Fraser (04:21):
Yeah, sure, sure.
And arteriovenous malformationis the most common cause of
hemorrhagic stroke in kids.
So a bleed in the brain,probably this happens.
Before birth, or maybe shortlyafterwards, the arteries, which
take very fast flowing blood,connect to veins which carry
blood back to your heart wherethey're not supposed to.
(04:42):
They're supposed to becapillaries in the middle.
If they connect incorrectly,they, they tend to have
something in the middle calledinus.
And those nidus tend to befragile and they can get bigger
over time and they can rupture,and that's when you run into
really big problems.
Arterio venous fistulas.
Often come from a trauma.
There's some sort of injury thathappens that will connect
(05:05):
arteries and veins.
It's not something you're bornwith a lot of the times, but it
can be.
And those tend to have very highflow blood so high that it can
take blood flow away from areasthat it needs to go and that can
cause really bad symptoms thateffect.
Yeah, we see those in traumapatients or, or patients after
a, a trauma to the facesometimes.
(05:26):
Usually those are treated bysurgeons.
And the vein of Galenmalformation is usually
something that you're born with.
The big issue is that there's.
A connection again between anartery and a big vein at the
center of your brain that leadsthat vein to get bigger and
bigger and bigger.
And it can cause all sorts ofproblems after you're born.
We usually watch those patientsvery, very closely'cause we're
(05:49):
trying to let them grow and getstronger before we treat it.
But if they start developingmajor symptoms, we, we have to
treat it earlier.
And a few people have startedtrying to treat them even before
Raylene Lewis (05:58):
birth.
Are the VMs the one where youtend to also see heart issues
the
Dr. Stuart Fraser (06:03):
most?
Yeah, so that's how babies willpresent classically.
And you or me our brain is.
Not that big compared to therest of our body.
I mean, it's big compared tomost other mammals, but it's,
it's not that big.
The majority of our blood flowis not going straight up to our
brain in a baby.
A lot of the blood flow is goingstraight to their brain.
(06:24):
So if you have this system whereblood is just going straight
from the artery to the vein andnot slowing down, the heart is
trying to perfuse the brain andthe blood is just bypassing it
so the heart beats harder andharder and harder until it goes
into what we call high outputheart failure.
Oh wow.
In my experience, and if youlook at some of the medical
literature out there, a lot ofthose kids have more
(06:46):
difficulties with school andlanguage later in life than I
think we would think becausethey look so great when they're
babies.
And it's important to rememberthat if you ever have brain
vessel disease, you might end uphaving some issues that you
didn't expect.
And we should always be watchfuland try to help if they do pop
up.
Raylene Lewis (07:04):
Super important because that's that's a problem.
I know, you know, my son Kylerhas been recovering.
He has a AVM that started out asa five, and a lot of people
don't realize that there'sanything wrong because he looks
completely normal and healthy onthe outside.
Yeah.
Now what about that C P
Dr. Stuart Fraser (07:21):
a Oh, cerebral per proliferative
angiopathy.
Okay.
Those are often confused withAVMs.
To be honest, I, I haven't had apatient who's had a cerebral
proliferative angiopathy thatwe've had to treat.
I will say there are a lot ofdifferent.
Brain vessel diseases out therethat we don't entirely
(07:42):
understand yet.
And this c p A is one where theytend to be bigger.
There's normal brain in between,and the treatment options are
different.
Raylene Lewis (07:51):
Okay.
Yeah, that's right.
Very, very diffuse as comparedto that compactus.
Yeah.
That we were talking aboutearlier.
Here's the next question, sorry.
Still going on and talking aboutkind of the, the MRIs and things
that, that parents read ingeneral.
First question was kind of likea granola type question.
How worried do parents have tobe about the tracer materials
that's found, like in a, in anmr i?
(08:13):
Because you know that an M R Idoes not use the same it's
different technology, so it's incontrast, right?
Versus a ct, which is like aradiation.
Dr. Stuart Fraser (08:23):
Okay, great question.
So if we're talking about theradiation that you receive, CAT
scans use x-ray radiation or thesame type of radiations as that
x-rays.
Have those can, if you getenough of it cause problems like
increased risk of cancer downthe road.
In extreme cases, you couldstart having cell injury, but
(08:45):
you'd have to get scan afterscan, after scan after scan for
a long, long time.
Generally.
The amount that is in a CAT scanis pretty safe.
We like to say it depends on theCAT scanner, but a lot of times
the amount of backgroundradiation you're getting in one
CAT scan is the equivalent tosay, a back a year of background
radiation of just walking aroundif you lived in any city in the
(09:07):
us something like that.
Radiation over time does causechanges in D N A, which can
cause cancer.
20, 30 years down the line.
We try to avoid CAT scans inchildren for this reason when we
can generally the amount of riskof direct harm from a CAT scan
is pretty low.
And then Mr.
(09:27):
Mri, as far as we know, thatjust uses magnets to try to take
pictures of the brain and body.
And as far as we can tell,they're absolutely no harmful
effects to to MRIs and humansare animals in which they've
been
Raylene Lewis (09:38):
tested on.
What about the contrast?
Because I know you do MRIs withand without, and the, with the
contrast shows like lesions, butthen you're injecting something.
Yeah.
Yeah.
What?
That's right.
So
Dr. Stuart Fraser (09:48):
whatcha injecting?
So the contrast goes so in Ct Ain cts, it's usually iodine
contrast that iodinated contrastwill make blood vessels light
up.
Because the contrast stays inblood vessels, but it will also
go to places that have lots ofblood going to them.
So sometimes they can help ussee abscesses or cancers.
(10:10):
Mostly what we use contrast forwith CAT scans are to take
really detailed pictures ofblood vessels.
We can't see them really withoutthem unless something's very
wrong.
Really, the only risk from theiodine is if you get too much of
it, it can cause kidney injury.
Your kidneys metabolize it.
And spit it out.
So for you or me, we get one,it, it really doesn't matter.
(10:31):
If you were to get them over andover and over again, this is why
we sometimes like to wait beforewe keep doing repeat ones.
Eventually it could cause kidneyinjury if you ever were to get
so much that your kidneys getoverwhelmed, extremely rare for
that to happen.
We do it in patients even withreally bad kidney disease if we
have to.
But it is, it is worthmentioning.
(10:51):
I've never actually had a caseof contrast induced kidney
damage, but we always talk aboutit.
Sure.
And then for MRIs we use GaddGAD contrast it's called, which
has the same purpose.
It lights up blood vessels andtumors, but in a way that the M
r I can detect it.
'cause M R MRI can't reallydetect the iodine.
And same issue it has to gothrough your kidneys when we're
finished with it.
(11:12):
In a young, healthy person,you're really not gonna notice,
but you do have to be carefulabout giving too much.
And there are some extremelyrare side effects that have been
reported in the literature thatagain, I haven't seen, but
they're, they're reported
Raylene Lewis (11:24):
for the most part, though, with both of these
types of contrast, it shouldflush out at the end, right.
Dr. Stuart Fraser (11:29):
You, you pee it out, you got it right.
That's the idea.
So you know, if you work out toohard, you might become really
sore'cause your body'soverwhelmed.
I kind of think of the liver andkidney as the same way as low
levels of toxins they can dealwith, with no lasting damage.
You just don't wanna do too muchtoo fast.
And in fact, even when thesurgeons or interventionalists
(11:51):
are doing angiograms with acatheter, they have calculations
they have to follow about howmuch contrast they're able to
ingest.
Raylene Lewis (11:58):
Okay.
Everybody knows what an x-rayis, right?
It's for bones.
Yeah.
A, a CT is kind of somethingthat helps you look at, at
fleshy tissue.
What's the difference betweenthe C T A and the M R A and what
people are looking for, likewith Okay,
Dr. Stuart Fraser (12:12):
good, good question.
Yeah.
It, they, they differ in the waythat they take images.
CAT scans are based on x-rays.
They shoot x-rays throughsomething, however much signal
goes through tells you how densewhatever it was passing through
was.
The cat scans are just a fancyx-ray that does it a million
times and makes that that threeD picture.
MRIs use a different techniqueto look at.
(12:35):
Theoretically the same thing.
So with the CAT scan, you'reshooting x-rays through and
hoping the iodine, which blocksa lot of radiation, will cause
the blood vessels to light up.
With an M r A, they use thesetimed pulse sequences.
They're taking a measure of howlong it takes hydrogen molecules
to switch after you send amagnetic pulse through them.
(12:56):
The computer can then do somecalculations to see areas where
they think there's water movingvery fast, and areas where water
is moving fast would be yourblood vessels, and that's what
creates the picture that we seewith MRIs.
Raylene Lewis (13:08):
So an MRI is kind of more detailed on just looking
at the blood vessels themselves.
Dr. Stuart Fraser (13:13):
That's actually a good question.
So, believe it or not,generally, not really.
As in more detail that, that, sothe m r A is a specific sequence
that only looks at the bloodvessels.
A C T A will look at bloodvessels specifically, but it
also sees the rest of the, thebrain RAs a lot of the times.
And, and it really depends onthe scanner you're using.
(13:34):
They can have trouble seeingsome of the things that we can
see on CAT scans.
But they also don't have anyradiation and usually we don't
have to use contrast for themeither.
And that's why I like to getthem especially in someone who a
lot of kids with strokes aregetting scanned over and over
again.
So we're thinking 20, 30 yearsdown the line, we'd like to
avoid the radiation.
Raylene Lewis (13:55):
Okay, so here's kind of a fun side note question
on that.
Right.
Okay.
So there is the good thingcalled security at the airport,
right?
Yeah.
And it's security at theairport.
They have these scanners.
And I know that scanners havecome a long way, but as a parent
of a kid who's already beenexposed a lot of times, should
we opt for the
Dr. Stuart Fraser (14:14):
pat down?
That is a good question.
The metal detectors, I don'tthink you have to worry about
lest I heard, and then those.
Those hands up one that theyhave.
Yeah.
The, the last I heard about thatthey're using non-ionizing
radiation and so it, itshouldn't increase your risk of,
of cancer.
Think you're okay to just not betouched.
(14:35):
And you can go like this andhands up.
Yeah, hands up.
We're here to party
Raylene Lewis (14:39):
Paul.
Right.
And we will look.
Forward to next month's episodewhere we continue our discussion
with the Director of thePediatric Stroke Program with
the McGovern Medical School atUT Health Houston, Dr.
Stewart Frazier, as he explainsa lot of the words we read on
the radiology reports, as wellas the squiggles parents see on
(15:00):
an e E G.
The doctor will also answerepilepsy questions, questions
about stroke in infants, andeven a few on stroke, and the C
Ovid 19 virus.
I hope you'll join us as wecontinue this discussion next
month.
The focus of this month's thanksto think about is based on the
(15:22):
Children's book, maybe aNautilus Award winner by Kobe
Yamada.
This book beautifully tells thestory that no matter our
circumstances or background,there is endless potential in
each one of us.
It is easy to wonder why.
Why am I here?
Why did this happen to me or tomy child?
(15:43):
To my life, but it can be hardto remember that you are the
only you there will ever be, andthat each one of us has
something very special to offer.
Even though our journey may beextremely hard with times where
we can only focus on the nextright thing, it is only when you
go on a journey that discoveriesare made on your path.
(16:07):
A time will come where you areThere.
To help in a way that only youcan, maybe it will be to help
others see the beauty in a day,shine a light into places that
have been dark for far too long,or speak up for those who cannot
speak for themselves.
Or maybe it will be somethingelse completely.
(16:29):
And although there will bestruggles and fears, And even
failure.
This world needs each one of usand the unique gifts that only
we can offer to those around us.
Thank you Kobe, for thisvaluable and important lesson.
And as always, if you havequestions or have a topic you
would like to hear about, don'tbe shy.
(16:51):
Share it in the comments and letus know.
And if you liked what you heardtoday, please go online and rate
this podcast.
Remember, you're never walkingthis journey alone.
Take care.
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