SE 2: Episode 1: The Doctor is IN: Brain Vessels, MRI, & CTs Explained

Raylene Lewis: 0:02

Hi there,and thank you for joining us on AVM Alliance,a pediatric podcast for families and friends whose lives have been affected by traumatic brain injury,rare disease,brain disorders,or stroke.The purpose of this podcast is to focus on the kid side of brain injury with honest talk news,information,and discussion for our community.Being a parent of a medically complex child is an extremely difficult path to suddenly find yourself on.I'm Raylene Lewis and my son Kyler suffered a hemorrhagic stroke at age15.Thank you for joining us.We are beginning our season with a three part:the Doctor is In series going over questions with a medical professional that parents have submitted to this podcast.This month's part one episode,will focus on the different radiology tests doctor's order Next month's Part two episode will continue the discussions on medical terms parents read on radiology reports,and also we'll go into more detail about the epilepsy and EEGs,as well as stroke in infants with part three,looking into questions about stem cells and other therapies and programs for kids who have suffered a stroke.Each episode for this season will end with a focus on a special children's book with the things to think about,takeaway,and don't forget,we now have a support group that meets monthly over Zoom,and we would truly love to have you join us.With me today.I have the Director of the Pediatric Stroke Program with the McGovern Medical School at UT Health Houston,Dr.Stuart Fraser.Dr.Fraser thank you for joining us.

Dr. Stuart Fraser: 1:43

Thanks for having me.I really appreciate the invite.

Raylene Lewis: 1:46

Oh,well we are just so excited.We know your time is very,very valuable.I have a list of questions people had asked us to start off.Now we have access to the reports and all the tests and scans that are done.And that leads me to a couple of just I guess,general medical school questions to start off with,if you don't mind.Okay.Those are fun.I'm happy to.One of the biggest things I think that parents look at is they wanna know the results of the scans and they wanna know what that means.But it's really hard to tell without Google right next to us.So really quick,can you explain the differences in the words on what we see between what is M C A P C A A C A?

Dr. Stuart Fraser: 2:30

Wow.Yes.I,I would be happy to,that is a second or third semester of med school.Question once,once you get to those,so what you're talking about are different arteries that are in the brain.So there are two big groups of arteries that go to your brain.Hopefully you're not watching violent movies,but if you are,you'll,you'll know about the ones on the front that you can feel with your two hands.Those are the carotid,and that supplies,we call that the anterior circulation.It supplies most of the front of your brain,and then in the back you can't feel it.You have the basilar artery and that supplies your brainstem.A lot of the back half of your brain,stuff that controls like vision and breathing and coordination.Those acronyms,people like use,talk about branches of those different big arteries.So the biggest,probably most important branch of your internal carotid artery,it's.The most common one that people get strokes in is the M C A,the middle cerebral artery.And not surprisingly,if you look at a cross section of the brain,it supplies the middle part.The a c A is the anterior cerebral artery,and the P c A is the posterior cerebral artery that comes from the the back that we talked about.

Raylene Lewis: 3:44

So the,the a c a is the front.

Dr. Stuart Fraser: 3:46

I'm greatly oversimplifying it,but yes,it's more front and in the middle.I think thinking of a anterior is front,middle is middle,and posterior is back.Would be a pretty good way to think about it.The brain can be a little counterintuitive,so when you look at the maps of what those territories are,they get sort of wonky.But yeah,that's a good way to think about it.I think.

Raylene Lewis: 4:06

Okay.And then talking about just a couple things that people show up with on diagnosis,can you just very briefly explain a V M and the difference between that and a v m fistula and then VO GM and then C P A?

Dr. Stuart Fraser: 4:21

Yeah,sure,sure.And arteriovenous malformation is the most common cause of hemorrhagic stroke in kids.So a bleed in the brain,probably this happens.Before birth,or maybe shortly afterwards,the arteries,which take very fast flowing blood,connect to veins which carry blood back to your heart where they're not supposed to.They're supposed to be capillaries in the middle.If they connect incorrectly,they,they tend to have something in the middle called inus.And those nidus tend to be fragile 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 that happens that will connect arteries and veins.It's not something you're born with a lot of the times,but it can be.And those tend to have very high flow blood so high that it can take blood flow away from areas that it needs to go and that can cause really bad symptoms that effect.Yeah,we see those in trauma patients or,or patients after a,a trauma to the face sometimes.Usually those are treated by surgeons.And the vein of Galen malformation is usually something that you're born with.The big issue is that there's.A connection again between an artery and a big vein at the center of your brain that leads that vein to get bigger and bigger and bigger.And it can cause all sorts of problems after you're born.We usually watch those patients very,very closely'cause we're trying to let them grow and get stronger before we treat it.But if they start developing major symptoms,we,we have to treat it earlier.And a few people have started trying to treat them even before

Raylene Lewis: 5:58

birth.Are the VMs the one where you tend to also see heart issues the

Dr. Stuart Fraser: 6:03

most?Yeah,so that's how babies will present classically.And you or me our brain is.Not that big compared to the rest of our body.I mean,it's big compared to most other mammals,but it's,it's not that big.The majority of our blood flow is not going straight up to our brain in a baby.A lot of the blood flow is going straight to their brain.So if you have this system where blood is just going straight from the artery to the vein and not slowing down,the heart is trying to perfuse the brain and the blood is just bypassing it so the heart beats harder and harder and harder until it goes into what we call high output heart failure.Oh wow.In my experience,and if you look at some of the medical literature out there,a lot of those kids have more difficulties with school and language later in life than I think we would think because they look so great when they're babies.And it's important to remember that if you ever have brain vessel disease,you might end up having some issues that you didn't expect.And we should always be watchful and try to help if they do pop up.

Raylene Lewis: 7:04

Super important because that's that's a problem.I know,you know,my son Kyler has been recovering.He has a AVM that started out as a five,and a lot of people don't realize that there's anything wrong because he looks completely normal and healthy on the outside.Yeah.Now what about that C P

Dr. Stuart Fraser: 7:21

a Oh,cerebral per proliferative angiopathy.Okay.Those are often confused with AVMs.To be honest,I,I haven't had a patient who's had a cerebral proliferative angiopathy that we've had to treat.I will say there are a lot of different.Brain vessel diseases out there that we don't entirely understand yet.And this c p A is one where they tend to be bigger.There's normal brain in between,and the treatment options are different.

Raylene Lewis: 7:51

Okay.Yeah,that's right.Very,very diffuse as compared to that compactus.Yeah.That we were talking about earlier.Here's the next question,sorry.Still going on and talking about kind of the,the MRIs and things that,that parents read in general.First question was kind of like a granola type question.How worried do parents have to be about the tracer materials that's found,like in a,in anm r i?Because you know that an M R I does not use the same it's different technology,so it's in contrast,right?Versus a ct,which is like a radiation.

Dr. Stuart Fraser: 8:23

Okay,great question.So if we're talking about the radiation that you receive,CAT scans use x-ray radiation or the same type of radiations as that x-rays.Have those can,if you get enough of it cause problems like increased risk of cancer down the road.In extreme cases,you could start having cell injury,but you'd have to get scan after scan,after scan after scan for a long,long time.Generally.The amount that is in a CAT scan is pretty safe.We like to say it depends on the CAT scanner,but a lot of times the amount of background radiation you're getting in one CAT scan is the equivalent to say,a back a year of background radiation of just walking around if you lived in any city in the us something like that.Radiation over time does cause changes in D N A,which can cause cancer.20,30years down the line.We try to avoid CAT scans in children for this reason when we can generally the amount of risk of direct harm from a CAT scan is pretty low.And then Mr.Mri,as far as we know,that just 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 humans are animals in which they've been

Raylene Lewis: 9:38

tested on.What about the contrast?Because I know you do MRIs with and without,and the,with the contrast shows like lesions,but then you're injecting something.Yeah.Yeah.What?That's right.So

Dr. Stuart Fraser: 9:48

whatcha injecting?So the contrast goes so in Ct A in cts,it's usually iodine contrast that iodinated contrast will make blood vessels light up.Because the contrast stays in blood vessels,but it will also go to places that have lots of blood going to them.So sometimes they can help us see abscesses or cancers.Mostly what we use contrast for with CAT scans are to take really detailed pictures of blood vessels.We can't see them really without them unless something's very wrong.Really,the only risk from the iodine 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.If you were to get them over and over and over again,this is why we sometimes like to wait before we keep doing repeat ones.Eventually it could cause kidney injury if you ever were to get so much that your kidneys get overwhelmed,extremely rare for that to happen.We do it in patients even with really bad kidney disease if we have to.But it is,it is worth mentioning.I've never actually had a case of contrast induced kidney damage,but we always talk about it.Sure.And then for MRIs we use Gadd GAD contrast it's called,which has the same purpose.It lights up blood vessels and tumors,but in a way that the M r I can detect it.'cause M R MRI can't really detect the iodine.And same issue it has to go through your kidneys when we're finished with it.In a young,healthy person,you're really not gonna notice,but you do have to be careful about giving too much.And there are some extremely rare side effects that have been reported in the literature that again,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 should flush 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 too hard,you might become really sore'cause your body's overwhelmed.I kind of think of the liver and kidney as the same way as low levels of toxins they can deal with,with no lasting damage.You just don't wanna do too much too fast.And in fact,even when the surgeons or interventionalists are doing angiograms with a catheter,they have calculations they have to follow about how much contrast they're able to ingest.

Raylene Lewis: 11:58

Okay.Everybody knows what an x-ray is,right?It's for bones.Yeah.A,a CT is kind of something that helps you look at,at fleshy tissue.What's the difference between the C T A and the M R A and what people are looking for,like with Okay,

Dr. Stuart Fraser: 12:12

good,good question.Yeah.It,they,they differ in the way that they take images.CAT scans are based on x-rays.They shoot x-rays through something,however much signal goes through tells you how dense whatever it was passing through was.The cat scans are just a fancy x-ray that does it a million times and makes that that three D picture.MRIs use a different technique to look at.Theoretically the same thing.So with the CAT scan,you're shooting x-rays through and hoping the iodine,which blocks a lot of radiation,will cause the blood vessels to light up.With an M r A,they use these timed pulse sequences.They're taking a measure of how long it takes hydrogen molecules to switch after you send a magnetic pulse through them.The computer can then do some calculations to see areas where they think there's water moving very fast,and areas where water is moving fast would be your blood vessels,and that's what creates the picture that we see with 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,so the m r A is a specific sequence that only looks at the blood vessels.A C T A will look at blood vessels specifically,but it also sees the rest of the,the brain RAs a lot of the times.And,and it really depends on the scanner you're using.They can have trouble seeing some of the things that we can see on CAT scans.But they also don't have any radiation and usually we don't have to use contrast for them either.And that's why I like to get them especially in someone who a lot of kids with strokes are getting scanned over and over again.So we're thinking20,30years down 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 thing called security at the airport,right?Yeah.And it's security at the airport.They have these scanners.And I know that scanners have come a long way,but as a parent of a kid who's already been exposed 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't think you have to worry about lest I heard,and then those.Those hands up one that they have.Yeah.The,the last I heard about that they're using non-ionizing radiation and so it,it shouldn't increase your risk of,of cancer.Think you're okay to just not be touched.And you can go like this and hands up.Yeah,hands up.We're here to party

Raylene Lewis: 14:39

Paul.Right.And we will look.Forward to next month's episode where we continue our discussion with the Director of the Pediatric Stroke Program with the McGovern Medical School at UT Health Houston,Dr.Stewart Frazier,as he explains a lot of the words we read on the radiology reports,as well as the squiggles parents see on an e E G.The doctor will also answer epilepsy questions,questions about stroke in infants,and even a few on stroke,and the C Ovid19virus.I hope you'll join us as we continue this discussion next month.The focus of this month's thanks to think about is based on the Children's book,maybe a Nautilus Award winner by Kobe Yamada.This book beautifully tells the story 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 to my child?To my life,but it can be hard to remember that you are the only you there will ever be,and that each one of us has something very special to offer.Even though our journey may be extremely hard with times where we can only focus on the next right thing,it is only when you go on a journey that discoveries are made on your path.A time will come where you are There.To help in a way that only you can,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 something else completely.And although there will be struggles and fears,And even failure.This world needs each one of us and the unique gifts that only we can offer to those around us.Thank you Kobe,for this valuable and important lesson.And as always,if you have questions or have a topic you would like to hear about,don't be shy.Share it in the comments and let us know.And if you liked what you heard today,please go online and rate this podcast.Remember,you're never walking this journey alone.Take care.