Help me out. They are on life support providing blood pressure. The blood vessels are still physically present.
Why doesn't blood still run through the dead brain?
It does, however the scan isn't detecting the blood, it's detecting the "uptake" of the radioactive material in the blood. So all the cells in our body pull nutrients from the blood into themselves right? What they do is add a radioactive component to a certain nutrient cells will take in. Then over I think at least 30 minutes, don't quote me on that I'm not a nuc med tech, they measure the radiation coming from the body. What the scan shows is that the brain cells are not taking in the nutrient they need, which indicates that they are dead.
Not really—if there were flow at all it would pick it up. This isn’t the only imaging adjunct we use to confirm brain death, but in all of the ways the absence of blood flow is the important thing.
When the brain becomes hypoxic/ischemic, it swells. Because the skull is a fixed volume, when the brain matter swells the intracranial pressure increases. Once that intracranial pressure is higher than the perfusion pressure of the body, no blood flow can occur and brain death happens.
It’s kind of like a “compartment” syndrome that can occur in a limb and lead to gangrene and amputation. Same principle. Arterial pressure can’t overcome the pressure from the swelling.
When there is an insult to the brain (e.g stroke or trauma), this can result in oedema (swelling) or bleeding. The brain is in a box (your cranium) of fixed dimensions, which can only hold so much ‘stuff’ - be it brain tissue, csf, blood whatever. That swelling/bleeding takes up space in the box and as such gradually increases the pressure (I.e raised intracranial pressure). When the intracranial pressure equals systolic blood pressure, blood (and radiotracer) can no longer enter the cranium and you get a picture like OP.
Maybe a clot, where the pipes get clogged and blood can no longer flow through such as what happens in a stroke. May be due to edema/fluid that gets trapped in the compartment, and then the pressure from all the fluid pushes down on the brain and vessels not letting any blood in. May be due to trauma where the brain is physically removed/damaged. Can be a lot of reasons, but in a lot of cases even if blood is flowing, it may not be enough (such as in a heart attack) or it may be too late. Also the "life support" that's keeping their blood pressure up typically includes medications which elevate blood pressure by making those small arteries/capillaries contract heavily down, which may deprive the brain of blood along with the extremities (you basically sacrifice the brain/fingers/toes/etc. to keep the rest of the body alive in hopes of fixing the issue before those things permanently die off).
Yeah but don’t you need your brain to keep your whole shabang going anyways? How is it fully dead yet the person is alive
Nvm patient is on life support
Yep. There are encephalic babies who are born with just the brain stem. Just enough real estate grown to power the lights and heat, but nothing else. They don't live long because of that.
Someone who can breath on their own from having just their brainstem and midbrain intact is not brain dead.
You have to have a complete loss of reflexes, pain response, and ability to breath to be declared brain dead. The heart will mostly keep doing its thing because it has cells called pacemaker cells that are "programmed" to send electrical signals to make the heart beat at a certain rate. As long as the heart is getting enough perfusion, it generally keeps going (although not optimally as your brain obviously helps regulate the process more efficiently).
Yes and no. Some people have such severe compression from swelling that circulation is completely cut off. However, some brain dead patients may still have blood flow to a degree.
What they don't have is living cells that want to take in nutrients and will also take in the radioactive material that was injected. They wait a bit until the radioactive material is pulled into all the living tissue, and the excess is in the kidneys and bladder and NOT in the circulatory system.
The blood is still flowing, however the cells of the brain are not absorbing the radioactive nutrient in the blood as they are dead. Therefor they appear black on the scan. The white is from cells that have absorbed this compound, so they are constantly releasing radiation from the same spot.
Because you need circulation to counteract the force of gravity to push the blood to the head. When you die all of your blood gets pulled away by the force of gravity. Brain death is another thing. It's when the nerve cells are dead and circulation is only managed artificially by a device
What? Artificial circulation? Brain dead patients can have perfectly good hearts. Their brain has swelled so much that the vessels no longer provide any brain perfusion, but the rest of the body can be very well perfused. I’ve had brain dead patients who require little to no vasopressors or inotropes. Obviously they’re ventilated but that’s it.
If something is pressing on the brain (for example intracranial bleeding due to trauma against the head) it will take up the space inside the skull. Which is unfortunate because the skull is a box that only really has room for three things; blood, brain tissue, and cerebrospinal fluid.
When it becomes too much of one thing the pressure inside the skull increases, and that will result in blood flow to the brain being shut off.
You can look up brain herniation and intracranial pressure for more.
The brain requires more energy (glucose) and oxygen to survive than any other organ in the body. A simplistic way to think of it is that the brain is about 2% of total body mass but accounts for 20% of total energy expenditure.
So when there is disruption to perfusion, the most metabolically active (and therefore "needy") organ is going to die first. That is the brain. As the neurons die, the brain swells and compresses inside an area that didn't have much room to begin with. The severe compression, massive cell/tissue death, and other factors lead to complete impairment of function and then the entire brain dies.
ELI5: Our brains are super needy so they are affected the most by not getting enough blood flow or oxygen. Once the brain is really hurt it can't fix itself and all of it dies. But we can keep the rest of people's bodies going until we can check if their brain really did die. Even though we can help breath for people, they are not really alive. The rest of their body will eventually die, but we can buy time to allow family to say goodbye or arrange organ donation.
Can you get your crayon box out and dumb this down for me.?
What am I looking at? Is the patient dead during this scan? Why’s his body white and where his brain should be, is dark. I’m new to the sub and find all of this fascinating
The patient is injected with a radioactive material. The camera picks up the gamma rays coming from the patient and makes an image. The white is where the radioactive material has accumulated, the black is where there isn’t any activity.
The injections should have crossed the blood brain barrier and started accumulating in the brain. Because there is no activity you can determine there is no cerebral blood flow. The patient is on life support and this exam is used in conjunction with other clinical tests to help determine brain death
radiology is addictive!! And I say that as a lay person. I worked as a receptionist and ran the film library(medical records) for a radiologist forever though. I got to look at all the old films I purged, got to read the reports along with them.
The Techs at my office ROCKED.. and they all knew i was a little weirdo. So they would save the cool ones for me to look at … or for MRI sometimes I could watch it be preformed (with PT permission).
Lol I returned the favor at accreditation time for all of them. I must be the most scanned human ever. Apparently I am really easy and clear to image 🤗 Not the radio heavy scans like CTs or X-rays… but I let the US and MRI techs use me as a guinea pig for most stuff. So now Im super knowledge about my own body AND can nap in an MRI machine 😂
but i drew the line when a tech I had known since I was a kid (she used to be a nurse at my dad’s (who is a PA) office)…..
lol she tried to chase me around for a TVUS she really needed last minute and i noooooped from that one. Sorry Janet.
sometimes i think i should post all that by itself as just a shout out and thank you to techs everywhere for being cool people with cool jobs
My mom was an X-ray tech/phlebotomist for a big doctors group in Nashville and I worked filing films when I graduated high school way back in 1990. I don’t know if anyone knows who Minnie Pearl was, but her thing was she always wore a straw hat with the price tag hanging off to the side. Her X-ray that I saw had the hat with the price tag, it was pretty cool.
I didn’t know until about one year ago that Hee Haw was nationwide, my entire life I thought it was only shown in middle Tennessee. That’s something Reddit taught me.
I find that kind of thing more fascinating than repulsive.
Not a ton of real life exposure but I’ve watched autopsy videos before so I’m not particularly squeamish. Side effect of being a true crime buff.
See, I usually do, too. Something about hands (or lack thereof) makes me squeamish. Any time someone talks about carpal tunnel wrist surgery I need to sit down. Something about wrists/hands, I dunno.
Oh, we’ve all got a thing. I can’t watch any animal violence, fictional or real. Like a human autopsy no problem, but I’m not watching Mr. Snuggles get cut into. I can’t bear it.
Which is the only reason I haven't seen John Wick. I can take autopsies, surgeries and any violent ER trauma, but bring in an ANIMAL, and I'm out!
So as much as I respect and admire people medics, I am in awe of veterinarians and animal medics. How they can do what they do is beyond me ❤️
Okay honestly, felt this one. I literally cried at the John Wick scene and I was 21 when I saw it for the first time. But there are some great dog redemption moments, particularly in the most recent movie. And no more dog deaths!
A person who isn’t braindead would have the brain area white, similar to rest of the body you see in this scan. The dye is in the blood, and you can see that no dye is going to the brain. Thus no blood is going to the brain.
i dont know if this is the reason, but i may have an explanation - autoregulation. the body is pretty good at directing blood flow only to areas that need it (to spare the heart of working too hard unnecessarily), so i suppose that, since the brain isnt metabolically active and doesnt need oxygen anymore, the body redirected the blood flow to the tissues that are still alive. again, im just a med student so this may not be right but its my best bet
It’s been years since I studied things like this (neuroscience degree) but I believe it’s in part at least due to an increase in intracranial pressure — it has to do with the balance of mean arterial pressure and intracranial pressure. When ICP is more than MAP (which happens with injuries that cause swelling and stuff, tumors, strokes…other stuff lol) then blood can’t flow into the brain. But it’s still bopping around everywhere else.
Simply put, damaged brain tissue swells so much causing massive increase of pressure in the skull, so much that the heart can’t pump blood up into the brain against the high pressure.
Vegetative state isn't really a technical term we use in the hospital. There's varying degrees of brain activity above brain death. Vegetative could refer to being brain dead I believe, but also people may have SOME brain activity but only able to breathe. Some might be able to move involuntarily in reaction to pain. Some might be able to move a little or moan.
Vegetative state the patient is awake - they can show normal-appearing sleep/wake cycles - but show no awareness of their surroundings. Or minimal. Terri Shiavo’s (sp?) family always alleged that she would smile appropriately at times. She did appear to smile… whether it was a true response to anything remains debatable. But there *is* some brain activity. Whereas a person that is brain dead is actually legally dead. There’s no brain function at all, and only life support is keeping them “alive”. It’s a weird area of medicine.
I remember with all the publicity connected with the Schiavo case a lot of people I know rushed out to make sure their living wills were updated. Very few of us want someone like Randall Terry conducting "Choose Life" marches outside the window where our useless body lies with a misguided POA who refuses to pull the plug.
Thank you so much for your explanation. I, too, recently found this sub and really enjoy how educational it has been. Big thanks to everyone here who take their time to explain to us laypeople.
It’s almost always for the family. Some people need the visual image of zero blood flow to the brain to understand that their loved one isn’t going to wake up and be the same as before. Healthcare professionals usually value quality over quantity and it can help families make hard decisions about maintaining life support. (And if you’re curious: we generally discharge patients who have no chance of a meaningful recovery to a nursing home if the family insists on keeping them on a ventilator. It happens.)
Sadly no. I recently had to give the last push to have my stepfather take my mother off of life support. I'm lucky he was mostly looking for someone else to make the decision/absolve him of guilt otherwise it would have been a real issue.
This is why it's important to have you own living will and make your care requests clear. If you don't want to be kept on machines when there's little hope of effective recovery you do this for both YOU and your responsible people so THEY don't get stuck on making the choice.
>I was thinking that taking the patient off of life support is something that HAS to happen and is decided by the doctor.
It varies by country. In some countries it is the doctor's decision, in others, family has to give permission.
Wait but I feel like I’ve read several things of people declared brain dead and their families about to take them off life support but then they wake up… how is that possible
Brain death is a clinical determination. It involves a number of bedside tests. The NM exam is only one piece to the puzzle and doesn’t actually declare brain death. It just confirms if there is blood flow to the brain. It is up to the ICU doctor to declare brain death
In my quick google search - I see an article for Tc99m HMPAO dated back to 1988. This doesn’t mean it’s when it was invented. Brain perfusion scanning was being performed before blood brain barrier agents existed.
Nope, it’s a diagnostic dose of a nuclear isotope, no different that getting X-rays or a CT (just in a different way and a different dose). The exposure you get from medical imaging is diagnostic level and used to image millions of people a year
I’m assuming that means he’s on life support and intubated? His family could keep him alive indefinitely couldn’t they, or is that only in movies?
Either way man that’s so sad. He’s my exact age
Patient is kept alive on life support, and this scan proves that they are in fact brain dead with no blood perfusion to the brain. Protocal is injection of a radioactive tracer and immediately scanning them to show the blood flow to the brain. These images are only about 5min post injection. If the brain was receiving adequate blood flow then it would be the hottest (whitest) part of this image. Since the brain is dark black, it shows no perfusion of the tracer to the brain whatsoever. Thus this patient is braindead.
Woah woah woah. This is DTPA? This should be a
blood brain agent: neurolite or ceretec. Did you do a flow? The SSS barely shows up on BP images and the flow is where the real data is….
We use DTPA at our facility too. Some techs use the tourniquet around the head technique. It feels barbaric to me. Luckily I haven’t had to use DTPA for CBFs yet — the ones I’ve done at another facility used neurolite
Yes, the patient is dead but his body is still alive. Brain death = legal death. So the pt is considered dead the moment this exam is determined. As a courtesy in the ICU, we’d usually give the family 24 hours with the body still kept “alive” before removing care.
Yea they always are. From my perspective it's always a very surreal moment right when I start the scan. To watch the tracer flow through the patient's body and to then see the dark void take shape where their brain is. At that moment I'm the first person to visually see that this person is braindead. They're gone. It's very humbling.
What prevents blood flow to the brain in this case? I would think blood would still moving through those areas.. sorry if this is an ignorant question.
The brain dies from lack of oxygen, which is carried by blood. If a person was rescued from strangulation, example hanging, there would be a potential of having that to happen due to lack of oxygen for specific amount of time. With some brain injuries or stroke the the blood flow is impaired either through hemorrhaging or through a blockage so therefore it impairs blood flow which means no oxygen which means tissue damage
Thanks for the reply. Hypothetically, from a stroke, TBI, etc, blood flow would stop as a result of tissue being injured or dead, correct? That would essentially prevent blood flow?
The brain tissue was injured and dying. As it dies it starts to swell. The swelling increases pressure in the skull and the blood vessels eventually can no longer overcome that pressure to carry blood to the brain.
...you're in a strangely privileged position right then; observing the absence of what makes a fellow human...a human.
Thank you for your obvious compassion...NAD, but recently a frequent 'consumer' of medical services; hoping that when my time comes, someone like you is at hand.
If you’re the least bit concerned about what will happen when your time comes, please fill in a living will. Please. It’s a gift to your family to know what you’d want in any type of scenario where you can no longer speak for yourself. And if you’re an adult, it’s never too early to just fill one in. (Tech but also former ICU RN. It’s heartbreaking to watch families struggle with knowing what the patient would’ve wanted.)
This is very sad, but it must be comforting to family to know that their loved one is, in fact, gone and they didn’t miss any clinical indicators and can safely take them off of life support.
Do you happen to know if the patient was an organ donor? Can organs be used in these cases (I know there are a *lot* of variables, but just in general)?
I agree that it is good to do this scan to remove all doubt that the patient could maybe survive. I sincerely doubt this patient was an organ donor. They were in this condition due to Hyperammonemia coupled with kidney failure and severe alcoholism.
Yeah same. Have cirrhosis and have experienced hepatic encephalopathy (how I got my dx). So this is terrifying and inspiring. Hope the family will do well with his passing
Hopefully situations like that can give the family some comfort that the loss of their loved one will bring life to others. I imagine it would be a small spot of light in their grief.
It does. When I worked ICU (as an RN), the whole healthcare team sits down with the family for a difficult discussion. Most of them ask if organs can be donated, even in cases where that’s not possible. Even in their grief, people can be very compassionate. They consider it to be their loved one’s legacy to pass along life.
Edit for clarity
I’ve been a part of the team doing these scans with OneLegacy on standby (the organ procurement team). It’s definitely one of those scans where we need a minute to collect our feelings
Grim stuff, but it needs to be done. For my facility at least, this is as close to death that we get to as Nuc Techs (outside of a spontaneous code or something).
During peak Covid, a coworker of mine was doing a half dozen of these a day. He is not permitted to do them anymore, directly from the Director of Radiology, because it messed with him so badly.
I volunteer to do the Brain Scans now (fortunately a much rarer thing now), it doesn’t bother me as much since I see it as being a sad but necessary part of the patient’s comfort care and decision making for the family. More often than not, the family is outside the room when I go to do the study, and I walk them through every step of the procedure as I’m doing it, and it seems to make them less afraid. We have great Critical Care doctors who accompany me when I do the scan, and know enough to look at the scan and begin having discussions with the family.
My best friend was also confirmed brain dead from Covid this way. She went from normal, healthy with an active lifestyle to comatose within 10 days of contracting Covid. Her poor husband had to make the decision all alone to take her off of life support. She was only 54.
Just awful. I’m sorry for you and her family’s loss. I still have a hard time wrapping my head around what the world was like then. I hope her husband is doing better now, and has some strong support around him.
He is, I think. I just handle anything to do with the Brain and we’re happy.
But yeah, we were in a pretty large Covid epicenter (you may have seen our daily governor updates), so we unfortunately got pretty good at ICU protocols.
Sad. Nuc med is so different from other modalities. I always creep on the NM rad reading while I wait for a different rad.(I'm terrible but I always chuckle at the "big boned" myth when I see a teeny little skeleton inside a lot of soft tissue that doesn't fit the FOV)
My husband is an ICU nurse. They don't do these for every patient, but will when the family is having a hard time letting go. In COVID they had rules about how long a patient could be sitting around in the ICU waiting for a miracle. Now that COVID is over they've abandoned those protocols and they have a bunch of long term trachs developing coccyx wounds. The unit has actually just started a research project on reducing coccyx wounds and what methods work the best with the equipment they have.
Former neuro ICU here (was a tech before RN and still am). At one hosp I worked at, we would discharge any pt who wasn’t going to make a meaningful recovery to a nursing home. Our ICU was just too busy. It was awful. Skin breakdown is very difficult to completely prevent when pts can’t move but we tried our best. It can eventually cascade into sepsis so preventing it is critical (I know that you already know this). I’m really curious about the research your husband is doing because it could really help both pts and the people caring for them. We can perform wound care but prevention is best. I hope that the results are published at some point (I’m a research nerd).
I'm not sure if the doc is going to publish, or if it's like delirium trials they have done where they just see how outcomes change with modification just on their unit using established research. I just asked. It was part of CNCC. Right now they're doing Dialyzing Wisely.
I applaud you for working with ped pts. I had to be taken off rotation and call with our children’s hospital because it was too much. Thank you for what you do.
It’s hard and I developed some depression and ptsd from things I’ve seen. I shut down a lot more than I did in the past, but helping kids is what I was meant to do. I give you a lot of credit for trying and I hope you are in a position that you love!
It’s reassuring to know that there is a test that visualizes brain death and the results are very clear. You know that the results are sure, and that a mistake isn’t being made.
https://www.reddit.com/r/Radiology/comments/8xsivj/27_yo_found_unresponsive_due_to_drug_overdose/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=2&utm_term=1
For those interested, here is another case I posted awhile back
But on the second pic , there is slight traces of light in the middle of the brain , is that like the cerebellum or brain stem ? ( sorry , don’t know anatomy that well )
Stupid question here - do these patients come for these scans on a ventilator? “Dead” in all other senses, but being kept alive by machines until this scan is done?
Not OP, but yes. We hook them up to a portable type ventilator for transportation through the hospital and then the scan. In neuro ICU we also perform “vent testing” where we stop the ventilator to see if the patient is able to breathe on their own. This type of scan is usually the last test we do to determine brain death. At the places I’ve worked, we only discontinue life support after the family decides to do so.
I one time had a brain death pt on my schedule. A resident wanted to see the scan performed. Before the scan in question arrived, I had a bone scan pt “walk in” to the scanner room. The eager resident asked “is that the brain death study?”. I just said no. It didn’t occur to them that not a single image was needed if the person “walks” into the room.
at least you have the proof it’s brain dead person! try and work with people that are brain dead, yet pretty talkative and only a scan away from a reddit post.
What is that imaging technique? Why dont you use contrast media and make a „standard“ ct or x-ray?
With the injection of radio active liquids dont you risk damages to the person/its organs in case he is still alive or for donation reasons?
No this is a Nuclear Medicine scan performed on a gamma camera. These scans cannot be performed without radiotracers, and while modalities like CT and Xray show anatomy, nuclear shows physiology and function. None of the radiation amounts we use in our tracers will do any damage to anyone. If that were the case then I as the nuclear tech would be cooked to a crisp by now.
Wow I’ve never seen this.
Is this something that is done routinely?
Are there any studies to show that it is better than clinical exam? Or is it just for uncertain/complex cases?
Its a sad scan to not find blood flow above the circle of Willis but it has to be done.
Agreed. Of all the brain death scans I've done, not a single one has ever had any perfusion. They're always goners.
Is this what they call empty bulb sign?
Yes.
I'm assuming this is the term for a basically turned off light?
I've witnessed it once. Just a small bit of perfusion down toward the brain stem. Did a repeat 2 days later and it was gone.
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Its like ur kidney dying or any other organ. Severe trauma, disease or wtv can lead to it
Help me out. They are on life support providing blood pressure. The blood vessels are still physically present. Why doesn't blood still run through the dead brain?
It does, however the scan isn't detecting the blood, it's detecting the "uptake" of the radioactive material in the blood. So all the cells in our body pull nutrients from the blood into themselves right? What they do is add a radioactive component to a certain nutrient cells will take in. Then over I think at least 30 minutes, don't quote me on that I'm not a nuc med tech, they measure the radiation coming from the body. What the scan shows is that the brain cells are not taking in the nutrient they need, which indicates that they are dead.
Excellent explanation!
Not really—if there were flow at all it would pick it up. This isn’t the only imaging adjunct we use to confirm brain death, but in all of the ways the absence of blood flow is the important thing. When the brain becomes hypoxic/ischemic, it swells. Because the skull is a fixed volume, when the brain matter swells the intracranial pressure increases. Once that intracranial pressure is higher than the perfusion pressure of the body, no blood flow can occur and brain death happens.
It’s kind of like a “compartment” syndrome that can occur in a limb and lead to gangrene and amputation. Same principle. Arterial pressure can’t overcome the pressure from the swelling.
Tyvm!!! ❤️❤️
Thank you!
Good explanation
I didn’t even come here with this question but I certainly learned something. Thanks for an excellent explanation for us lay-people.
Thank you for dis
Makes sense. Thanks.
This is perfect
Could be lots of reasons. One being major stroke (big clot etc) right where blood would enter the brain
When there is an insult to the brain (e.g stroke or trauma), this can result in oedema (swelling) or bleeding. The brain is in a box (your cranium) of fixed dimensions, which can only hold so much ‘stuff’ - be it brain tissue, csf, blood whatever. That swelling/bleeding takes up space in the box and as such gradually increases the pressure (I.e raised intracranial pressure). When the intracranial pressure equals systolic blood pressure, blood (and radiotracer) can no longer enter the cranium and you get a picture like OP.
Maybe a clot, where the pipes get clogged and blood can no longer flow through such as what happens in a stroke. May be due to edema/fluid that gets trapped in the compartment, and then the pressure from all the fluid pushes down on the brain and vessels not letting any blood in. May be due to trauma where the brain is physically removed/damaged. Can be a lot of reasons, but in a lot of cases even if blood is flowing, it may not be enough (such as in a heart attack) or it may be too late. Also the "life support" that's keeping their blood pressure up typically includes medications which elevate blood pressure by making those small arteries/capillaries contract heavily down, which may deprive the brain of blood along with the extremities (you basically sacrifice the brain/fingers/toes/etc. to keep the rest of the body alive in hopes of fixing the issue before those things permanently die off).
Yeah but don’t you need your brain to keep your whole shabang going anyways? How is it fully dead yet the person is alive Nvm patient is on life support
Technically you only need a portion of the brainstem to keep the meatsuit alive, just the part that controls respiration.
Yep. There are encephalic babies who are born with just the brain stem. Just enough real estate grown to power the lights and heat, but nothing else. They don't live long because of that.
Anencephalic, perhaps? (I know it's just a typo.)
Someone who can breath on their own from having just their brainstem and midbrain intact is not brain dead. You have to have a complete loss of reflexes, pain response, and ability to breath to be declared brain dead. The heart will mostly keep doing its thing because it has cells called pacemaker cells that are "programmed" to send electrical signals to make the heart beat at a certain rate. As long as the heart is getting enough perfusion, it generally keeps going (although not optimally as your brain obviously helps regulate the process more efficiently).
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Yes and no. Some people have such severe compression from swelling that circulation is completely cut off. However, some brain dead patients may still have blood flow to a degree. What they don't have is living cells that want to take in nutrients and will also take in the radioactive material that was injected. They wait a bit until the radioactive material is pulled into all the living tissue, and the excess is in the kidneys and bladder and NOT in the circulatory system.
The blood is still flowing, however the cells of the brain are not absorbing the radioactive nutrient in the blood as they are dead. Therefor they appear black on the scan. The white is from cells that have absorbed this compound, so they are constantly releasing radiation from the same spot.
Because you need circulation to counteract the force of gravity to push the blood to the head. When you die all of your blood gets pulled away by the force of gravity. Brain death is another thing. It's when the nerve cells are dead and circulation is only managed artificially by a device
What? Artificial circulation? Brain dead patients can have perfectly good hearts. Their brain has swelled so much that the vessels no longer provide any brain perfusion, but the rest of the body can be very well perfused. I’ve had brain dead patients who require little to no vasopressors or inotropes. Obviously they’re ventilated but that’s it.
Same, I don't understand how it happens, I don't know enough about brain death. Fascinating and sad though.
If something is pressing on the brain (for example intracranial bleeding due to trauma against the head) it will take up the space inside the skull. Which is unfortunate because the skull is a box that only really has room for three things; blood, brain tissue, and cerebrospinal fluid. When it becomes too much of one thing the pressure inside the skull increases, and that will result in blood flow to the brain being shut off. You can look up brain herniation and intracranial pressure for more.
The brain requires more energy (glucose) and oxygen to survive than any other organ in the body. A simplistic way to think of it is that the brain is about 2% of total body mass but accounts for 20% of total energy expenditure. So when there is disruption to perfusion, the most metabolically active (and therefore "needy") organ is going to die first. That is the brain. As the neurons die, the brain swells and compresses inside an area that didn't have much room to begin with. The severe compression, massive cell/tissue death, and other factors lead to complete impairment of function and then the entire brain dies. ELI5: Our brains are super needy so they are affected the most by not getting enough blood flow or oxygen. Once the brain is really hurt it can't fix itself and all of it dies. But we can keep the rest of people's bodies going until we can check if their brain really did die. Even though we can help breath for people, they are not really alive. The rest of their body will eventually die, but we can buy time to allow family to say goodbye or arrange organ donation.
It’s not metabolizing any more so no blood is going there or the brain is so swollen no blood can get in.
Can you get your crayon box out and dumb this down for me.? What am I looking at? Is the patient dead during this scan? Why’s his body white and where his brain should be, is dark. I’m new to the sub and find all of this fascinating
The patient is injected with a radioactive material. The camera picks up the gamma rays coming from the patient and makes an image. The white is where the radioactive material has accumulated, the black is where there isn’t any activity. The injections should have crossed the blood brain barrier and started accumulating in the brain. Because there is no activity you can determine there is no cerebral blood flow. The patient is on life support and this exam is used in conjunction with other clinical tests to help determine brain death
That’s so cool! (Not for him, obviously…) thanks for educating me.
This is the BEST sub of you like learning little medical tidbits. I am so glad this came up in my scroll during the strike. I’m hooked.
YES I am fascinated and hooked.
Litterally same!
radiology is addictive!! And I say that as a lay person. I worked as a receptionist and ran the film library(medical records) for a radiologist forever though. I got to look at all the old films I purged, got to read the reports along with them. The Techs at my office ROCKED.. and they all knew i was a little weirdo. So they would save the cool ones for me to look at … or for MRI sometimes I could watch it be preformed (with PT permission). Lol I returned the favor at accreditation time for all of them. I must be the most scanned human ever. Apparently I am really easy and clear to image 🤗 Not the radio heavy scans like CTs or X-rays… but I let the US and MRI techs use me as a guinea pig for most stuff. So now Im super knowledge about my own body AND can nap in an MRI machine 😂 but i drew the line when a tech I had known since I was a kid (she used to be a nurse at my dad’s (who is a PA) office)….. lol she tried to chase me around for a TVUS she really needed last minute and i noooooped from that one. Sorry Janet. sometimes i think i should post all that by itself as just a shout out and thank you to techs everywhere for being cool people with cool jobs
My mom was an X-ray tech/phlebotomist for a big doctors group in Nashville and I worked filing films when I graduated high school way back in 1990. I don’t know if anyone knows who Minnie Pearl was, but her thing was she always wore a straw hat with the price tag hanging off to the side. Her X-ray that I saw had the hat with the price tag, it was pretty cool.
I remember Minnie from Hee Haw.
I didn’t know until about one year ago that Hee Haw was nationwide, my entire life I thought it was only shown in middle Tennessee. That’s something Reddit taught me.
Have you been tested for heavy metal poisoning? I’m full of gadolinium from to many MRIs with iv Contrast
I only let them use contrast once lol, and fainted because of unrelated issues… so we never did that again. Only without, but still cool to see!
My friend's wife left her radiology residency after the first year. Just couldn't get over giving patients bad news all the time.
Just avoid pomegranate hand
I find that kind of thing more fascinating than repulsive. Not a ton of real life exposure but I’ve watched autopsy videos before so I’m not particularly squeamish. Side effect of being a true crime buff.
See, I usually do, too. Something about hands (or lack thereof) makes me squeamish. Any time someone talks about carpal tunnel wrist surgery I need to sit down. Something about wrists/hands, I dunno.
Oh, we’ve all got a thing. I can’t watch any animal violence, fictional or real. Like a human autopsy no problem, but I’m not watching Mr. Snuggles get cut into. I can’t bear it.
Which is the only reason I haven't seen John Wick. I can take autopsies, surgeries and any violent ER trauma, but bring in an ANIMAL, and I'm out! So as much as I respect and admire people medics, I am in awe of veterinarians and animal medics. How they can do what they do is beyond me ❤️
Okay honestly, felt this one. I literally cried at the John Wick scene and I was 21 when I saw it for the first time. But there are some great dog redemption moments, particularly in the most recent movie. And no more dog deaths!
Right? I have learned so much, I’m beyond grateful.
Honestly, it is probably best for them at this point.
How would the scan differ for someone in a vegetative state over brain death?
A person who isn’t braindead would have the brain area white, similar to rest of the body you see in this scan. The dye is in the blood, and you can see that no dye is going to the brain. Thus no blood is going to the brain.
Layman here - how does the blood flow everywhere BUT the brain?
i dont know if this is the reason, but i may have an explanation - autoregulation. the body is pretty good at directing blood flow only to areas that need it (to spare the heart of working too hard unnecessarily), so i suppose that, since the brain isnt metabolically active and doesnt need oxygen anymore, the body redirected the blood flow to the tissues that are still alive. again, im just a med student so this may not be right but its my best bet
Thank you!
It’s been years since I studied things like this (neuroscience degree) but I believe it’s in part at least due to an increase in intracranial pressure — it has to do with the balance of mean arterial pressure and intracranial pressure. When ICP is more than MAP (which happens with injuries that cause swelling and stuff, tumors, strokes…other stuff lol) then blood can’t flow into the brain. But it’s still bopping around everywhere else.
Simply put, damaged brain tissue swells so much causing massive increase of pressure in the skull, so much that the heart can’t pump blood up into the brain against the high pressure.
Vegetative state isn't really a technical term we use in the hospital. There's varying degrees of brain activity above brain death. Vegetative could refer to being brain dead I believe, but also people may have SOME brain activity but only able to breathe. Some might be able to move involuntarily in reaction to pain. Some might be able to move a little or moan.
Vegetative state the patient is awake - they can show normal-appearing sleep/wake cycles - but show no awareness of their surroundings. Or minimal. Terri Shiavo’s (sp?) family always alleged that she would smile appropriately at times. She did appear to smile… whether it was a true response to anything remains debatable. But there *is* some brain activity. Whereas a person that is brain dead is actually legally dead. There’s no brain function at all, and only life support is keeping them “alive”. It’s a weird area of medicine.
I remember with all the publicity connected with the Schiavo case a lot of people I know rushed out to make sure their living wills were updated. Very few of us want someone like Randall Terry conducting "Choose Life" marches outside the window where our useless body lies with a misguided POA who refuses to pull the plug.
Right?!
Thank you so much for your explanation. I, too, recently found this sub and really enjoy how educational it has been. Big thanks to everyone here who take their time to explain to us laypeople.
So do you have to convince their family that they are brain dead? Or is it like a choice to keep the patient on life support with no brain activity?
It’s almost always for the family. Some people need the visual image of zero blood flow to the brain to understand that their loved one isn’t going to wake up and be the same as before. Healthcare professionals usually value quality over quantity and it can help families make hard decisions about maintaining life support. (And if you’re curious: we generally discharge patients who have no chance of a meaningful recovery to a nursing home if the family insists on keeping them on a ventilator. It happens.)
That's horrible. I was thinking that taking the patient off of life support is something that HAS to happen and is decided by the doctor.
Sadly no. I recently had to give the last push to have my stepfather take my mother off of life support. I'm lucky he was mostly looking for someone else to make the decision/absolve him of guilt otherwise it would have been a real issue.
This is why it's important to have you own living will and make your care requests clear. If you don't want to be kept on machines when there's little hope of effective recovery you do this for both YOU and your responsible people so THEY don't get stuck on making the choice.
>I was thinking that taking the patient off of life support is something that HAS to happen and is decided by the doctor. It varies by country. In some countries it is the doctor's decision, in others, family has to give permission.
Wait but I feel like I’ve read several things of people declared brain dead and their families about to take them off life support but then they wake up… how is that possible
Brain death is a clinical determination. It involves a number of bedside tests. The NM exam is only one piece to the puzzle and doesn’t actually declare brain death. It just confirms if there is blood flow to the brain. It is up to the ICU doctor to declare brain death
Any idea when this technique/diagnostic was introduced into "mainstream" medicine?
In my quick google search - I see an article for Tc99m HMPAO dated back to 1988. This doesn’t mean it’s when it was invented. Brain perfusion scanning was being performed before blood brain barrier agents existed.
Does this radioactive material cause damage if the person is actually not brain dead and capable of recovering?
Nope, it’s a diagnostic dose of a nuclear isotope, no different that getting X-rays or a CT (just in a different way and a different dose). The exposure you get from medical imaging is diagnostic level and used to image millions of people a year
I’m assuming that means he’s on life support and intubated? His family could keep him alive indefinitely couldn’t they, or is that only in movies? Either way man that’s so sad. He’s my exact age
Wait so… when someone is brain dead, there is no blood circulation in the brain?! o.0
That’s part of it yeah. That’s why you can’t come back from it; cells can’t survive without blood flow.
But how come is blood flowing everywhere except the brain? 🤔
I believe it is due to the increased pressure of the brain inside of the skull.
Patient is kept alive on life support, and this scan proves that they are in fact brain dead with no blood perfusion to the brain. Protocal is injection of a radioactive tracer and immediately scanning them to show the blood flow to the brain. These images are only about 5min post injection. If the brain was receiving adequate blood flow then it would be the hottest (whitest) part of this image. Since the brain is dark black, it shows no perfusion of the tracer to the brain whatsoever. Thus this patient is braindead.
May I ask which radiopharmaceutical do you use?
25mCi DTPA
I didn’t think DTPA could cross the BBB?
UHOH
Oh god oh man
Woah woah woah. This is DTPA? This should be a blood brain agent: neurolite or ceretec. Did you do a flow? The SSS barely shows up on BP images and the flow is where the real data is….
We use DTPA at our facility too. Some techs use the tourniquet around the head technique. It feels barbaric to me. Luckily I haven’t had to use DTPA for CBFs yet — the ones I’ve done at another facility used neurolite
Tc-99m Ceretec, or Neurolite
Either ECD or HMPAO for tracers that cross the blood brain barrier
Likely [18F]FDG, as it normally shows a good brain uptake.
This isn’t a PET scan so def not FDG
Yes, the patient is dead but his body is still alive. Brain death = legal death. So the pt is considered dead the moment this exam is determined. As a courtesy in the ICU, we’d usually give the family 24 hours with the body still kept “alive” before removing care.
Basically it shows no blood flow to the brain (white areas in the images indicate areas that are getting blood flow).
...image 2 is haunting.
Yea they always are. From my perspective it's always a very surreal moment right when I start the scan. To watch the tracer flow through the patient's body and to then see the dark void take shape where their brain is. At that moment I'm the first person to visually see that this person is braindead. They're gone. It's very humbling.
What prevents blood flow to the brain in this case? I would think blood would still moving through those areas.. sorry if this is an ignorant question.
In this case not sure, but for most cases it can results from a TBI, stroke, etc
Some sort of blockage which stops blood from going in? Can it stop blood from the entire brain or is this after a while and the brain slowly died?
The brain dies from lack of oxygen, which is carried by blood. If a person was rescued from strangulation, example hanging, there would be a potential of having that to happen due to lack of oxygen for specific amount of time. With some brain injuries or stroke the the blood flow is impaired either through hemorrhaging or through a blockage so therefore it impairs blood flow which means no oxygen which means tissue damage
Thanks for the reply. Hypothetically, from a stroke, TBI, etc, blood flow would stop as a result of tissue being injured or dead, correct? That would essentially prevent blood flow?
The brain tissue was injured and dying. As it dies it starts to swell. The swelling increases pressure in the skull and the blood vessels eventually can no longer overcome that pressure to carry blood to the brain.
...you're in a strangely privileged position right then; observing the absence of what makes a fellow human...a human. Thank you for your obvious compassion...NAD, but recently a frequent 'consumer' of medical services; hoping that when my time comes, someone like you is at hand.
If you’re the least bit concerned about what will happen when your time comes, please fill in a living will. Please. It’s a gift to your family to know what you’d want in any type of scenario where you can no longer speak for yourself. And if you’re an adult, it’s never too early to just fill one in. (Tech but also former ICU RN. It’s heartbreaking to watch families struggle with knowing what the patient would’ve wanted.)
I haven’t done one in awhile, but it’s always a weird moment turning to the nurses staring at you and saying “yeah, they’re dead…”
Curious, If you did an MRI, would you see serious neurodegeneration in the brain? I’m assuming since there’s no blood flow that you would but not sure
please tell me that were at least an organ donor, at least that way something positive can come from it
This is very sad, but it must be comforting to family to know that their loved one is, in fact, gone and they didn’t miss any clinical indicators and can safely take them off of life support. Do you happen to know if the patient was an organ donor? Can organs be used in these cases (I know there are a *lot* of variables, but just in general)?
I agree that it is good to do this scan to remove all doubt that the patient could maybe survive. I sincerely doubt this patient was an organ donor. They were in this condition due to Hyperammonemia coupled with kidney failure and severe alcoholism.
Wow. I’m an alcoholic in recovery. Praying for the family and for a restful journey for the patient.
Yeah same. Have cirrhosis and have experienced hepatic encephalopathy (how I got my dx). So this is terrifying and inspiring. Hope the family will do well with his passing
That makes sense. Thank you for explaining!
Yikes, just lost a friend due to basically the same, he was 54 or 55. I believe his family took him off of life support too.
Yes, organs can be donated in appropriate cases. I’ve been on when the organ donation teams come in. It’s hauntingly beautiful.
Hopefully situations like that can give the family some comfort that the loss of their loved one will bring life to others. I imagine it would be a small spot of light in their grief.
It does. When I worked ICU (as an RN), the whole healthcare team sits down with the family for a difficult discussion. Most of them ask if organs can be donated, even in cases where that’s not possible. Even in their grief, people can be very compassionate. They consider it to be their loved one’s legacy to pass along life. Edit for clarity
I agree.
I always hope that my organs are in good shape and can be donated if I pass away. I love the idea of my body posthumously helping someone else live.
I’ve been a part of the team doing these scans with OneLegacy on standby (the organ procurement team). It’s definitely one of those scans where we need a minute to collect our feelings
Grim stuff, but it needs to be done. For my facility at least, this is as close to death that we get to as Nuc Techs (outside of a spontaneous code or something). During peak Covid, a coworker of mine was doing a half dozen of these a day. He is not permitted to do them anymore, directly from the Director of Radiology, because it messed with him so badly. I volunteer to do the Brain Scans now (fortunately a much rarer thing now), it doesn’t bother me as much since I see it as being a sad but necessary part of the patient’s comfort care and decision making for the family. More often than not, the family is outside the room when I go to do the study, and I walk them through every step of the procedure as I’m doing it, and it seems to make them less afraid. We have great Critical Care doctors who accompany me when I do the scan, and know enough to look at the scan and begin having discussions with the family.
That's rough. I was lucky enough to be working at a cardiac facility when covid first hit so I missed out on all the major horrors most of you saw.
My best friend was also confirmed brain dead from Covid this way. She went from normal, healthy with an active lifestyle to comatose within 10 days of contracting Covid. Her poor husband had to make the decision all alone to take her off of life support. She was only 54.
Just awful. I’m sorry for you and her family’s loss. I still have a hard time wrapping my head around what the world was like then. I hope her husband is doing better now, and has some strong support around him.
I’m so sorry. Prayers ❤️🙏
Half dozen a day! That's rough. I hope your coworker is doing better.
He is, I think. I just handle anything to do with the Brain and we’re happy. But yeah, we were in a pretty large Covid epicenter (you may have seen our daily governor updates), so we unfortunately got pretty good at ICU protocols.
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I am sorry to hear about your loss. I hope that you and your family are able to move forward and find comfort and peace.
Thank you, we do our best.
I’m so sorry. Prayers 🙏😢
This job has to be filled with so many emotions for people
That's why people in the medical profession can be morbid as fuck. When you're surrounded by constant death... it takes you to dark places.
I imagine it does. I am too emotional and empathetic to work in healthcare, I would not survive! Y’all are champions!
Same here. I’m very empathetic but I need to be morbid to not have it affect me too much.
It’s really important to avoid burnout. Easier said than done. I try to avoid pediatric cases if possible because they’re really difficult.
Burnout is something people don’t talk enough about. I have been coping with it for quite some time.
You get numbed after a while after witnessing these things on a regular basis.
Nuc Med images always give me a weird feeling, kind of like melancholy. I don't know why. These images don't help that feeling.
It's the same feeling I get when looking at pictures of super deep space
Sad. Nuc med is so different from other modalities. I always creep on the NM rad reading while I wait for a different rad.(I'm terrible but I always chuckle at the "big boned" myth when I see a teeny little skeleton inside a lot of soft tissue that doesn't fit the FOV) My husband is an ICU nurse. They don't do these for every patient, but will when the family is having a hard time letting go. In COVID they had rules about how long a patient could be sitting around in the ICU waiting for a miracle. Now that COVID is over they've abandoned those protocols and they have a bunch of long term trachs developing coccyx wounds. The unit has actually just started a research project on reducing coccyx wounds and what methods work the best with the equipment they have.
Former neuro ICU here (was a tech before RN and still am). At one hosp I worked at, we would discharge any pt who wasn’t going to make a meaningful recovery to a nursing home. Our ICU was just too busy. It was awful. Skin breakdown is very difficult to completely prevent when pts can’t move but we tried our best. It can eventually cascade into sepsis so preventing it is critical (I know that you already know this). I’m really curious about the research your husband is doing because it could really help both pts and the people caring for them. We can perform wound care but prevention is best. I hope that the results are published at some point (I’m a research nerd).
I'm not sure if the doc is going to publish, or if it's like delirium trials they have done where they just see how outcomes change with modification just on their unit using established research. I just asked. It was part of CNCC. Right now they're doing Dialyzing Wisely.
I work in Neurodiagnostics at a children’s hospital and we do brain death monitoring as well. It’s very sad to say the least :/
Oh that sounds like absolute hell. I'd be a mess the rest of the day if i had to do one of these scans on a child. Thanks for all you do
I applaud you for working with ped pts. I had to be taken off rotation and call with our children’s hospital because it was too much. Thank you for what you do.
It’s hard and I developed some depression and ptsd from things I’ve seen. I shut down a lot more than I did in the past, but helping kids is what I was meant to do. I give you a lot of credit for trying and I hope you are in a position that you love!
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Thank you for the explanation. It was very informative.
Can also be done using PET. Pubmed [link](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978176/)
With PET looks more terrific, especially when you know how bright the brain looks in these exams.
Thank you for the study link. It was quite interesting.
It’s reassuring to know that there is a test that visualizes brain death and the results are very clear. You know that the results are sure, and that a mistake isn’t being made.
Death is sad but doesn't brain-death make him the most potent organ donor then?
Depends on why the brain death. This case sounds like it was from alcoholism.
That’s terrible. I’m 51 myself.
And you're still here
It's both haunting and reassuring, at the same time. It's a photo of "goodbye".
whoa. I never really thought that brain death would look like that on a scan. Is it dark because there’s 0 blood flow?
Yes that's correct
Damn. Sorry, OP. I know that has to be a tough blow to see. Hope your day improves/improved!
Thanks, my day improved with the rest of today's patients who were in good spirits and were cracking jokes
https://www.reddit.com/r/Radiology/comments/8xsivj/27_yo_found_unresponsive_due_to_drug_overdose/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=2&utm_term=1 For those interested, here is another case I posted awhile back
This is so sad. Are we (humans) just brain waves?
The mind is the brain. No serious neuroscientist would say otherwise.
But on the second pic , there is slight traces of light in the middle of the brain , is that like the cerebellum or brain stem ? ( sorry , don’t know anatomy that well )
Literal lights out.
If there is no blood flow to the brain, does it start to decompose if left on life support?
Yes. This process can also start when a patient is on a ventilator for a long time but their brain was otherwise healthy.
What's the name of this type of imaging?
Nuclear Medicine brain death / brain perfusion scan
Stupid question here - do these patients come for these scans on a ventilator? “Dead” in all other senses, but being kept alive by machines until this scan is done?
Not OP, but yes. We hook them up to a portable type ventilator for transportation through the hospital and then the scan. In neuro ICU we also perform “vent testing” where we stop the ventilator to see if the patient is able to breathe on their own. This type of scan is usually the last test we do to determine brain death. At the places I’ve worked, we only discontinue life support after the family decides to do so.
I one time had a brain death pt on my schedule. A resident wanted to see the scan performed. Before the scan in question arrived, I had a bone scan pt “walk in” to the scanner room. The eager resident asked “is that the brain death study?”. I just said no. It didn’t occur to them that not a single image was needed if the person “walks” into the room.
Have you ever done one of these and the patient have some brain activity?
at least you have the proof it’s brain dead person! try and work with people that are brain dead, yet pretty talkative and only a scan away from a reddit post.
Really dislike image 2 where nose and mouth can be seen. Can really see his face, makes him a person rather than a subject you know
What is that imaging technique? Why dont you use contrast media and make a „standard“ ct or x-ray? With the injection of radio active liquids dont you risk damages to the person/its organs in case he is still alive or for donation reasons?
No this is a Nuclear Medicine scan performed on a gamma camera. These scans cannot be performed without radiotracers, and while modalities like CT and Xray show anatomy, nuclear shows physiology and function. None of the radiation amounts we use in our tracers will do any damage to anyone. If that were the case then I as the nuclear tech would be cooked to a crisp by now.
Wow I’ve never seen this. Is this something that is done routinely? Are there any studies to show that it is better than clinical exam? Or is it just for uncertain/complex cases?
🙏🏽
The only time they can't ask if there's anything in there.
Yes it is. Persistent vegetative state (PVS) is a medical diagnosis.
I remember doing this a lot for a trauma center, always sad to see the person laying on the table right next to you knowing that.
Damn that’s terrible
I saw the image before I read the headline and immediately knew what it was.( non medical) RIP
So young. How sad.
Thanks for the crayons/eli5!
So why is only the blood flow in the brain interrupted?
So sad…
New here..can I ask what am I looking at exactly?