Every time I've gotten an MRI the doctors and techs have sworn up and down it's impossible for this stuff to stick around. Getting tired of not being able to believe what doctors say...
That's surprising, it's at least casually known that they're bio accumulative to some extent. I've joked to the techs before about gadolinium eventually accumulating enough to not be necessary if you do it with enough frequency. Realistically though any situation that you're doing the contrast you're probably at a lot more risk of whatever they've found than from the contrast agent.
I had to have contrast to diagnose a simple cyst, which is entirely asymptomatic and was discovered by accident in the background of a cardiac MRI (family history of SCD, but my own heart is fine).
You're making me feel lucky about what was otherwise a very unpleasant experience!
A chemist gave a great talk about this at a big MRI conference (ISMRM) in Paris 10ish years ago. His explanation was that gad behaves a lot like iron does in the body. It deposits where iron does and like iron it lacks a metabolic route for removal (though menstruating females lose iron).
He stated that deposition was entirely predictable. However the harm caused is still debated.
The article here says ‘ Dr Wagner theorized that nanoparticle formation could trigger a disproportionate immune response, with affected cells sending distress signals that intensify the body’s reaction.’
Emphasis on ‘theorised’.
Deposition is discussed in the below link, and the comparison with iron is briefly mentioned.
Maybe, but I was taking an immense amount of vitamin C as prescribed by the doc to bootstrap the healing process.
So this reveals to me two issues
1. In general side effects of the contrast agent are not communicated properly. If I knew, I might have asked - hey can you do the analysis without the agent?
2. There’s no recommendation to avoid vitamin C prior and right after the MRI, heightening the risk.
Maybe donate some plasma afterward. There was a study about firefighters exposed to microplastics that had a statistical reduction after regular donations.
> I was kind of annoyed I wasn't offered and MRI, and here we are.
This paper isn’t saying that MRI contrast agent is high risk in general.
There’s a risk in misinterpreting these niche papers to overstate their relative risk. This is a common mistake when people start reading medical papers and begin overweighting the things they’ve read about as the most significant risks.
CT is cheaper than MRI, and it's harder to get insurance to pay for the latter. There are some legitimate diagnostic reasons to prefer CT imagery, but I think cost may be a more common deciding factor.
> I agree. Expecting perfection from humans, even experts, is not reasonable and is frankly counterproductive.
There's a big difference between perfection and "Statistical Literacy Among Doctors Now Lower Than Chance"[1]. I don't think their intentions are bad, but they are woefully incompetent at many basic things.
> There's a big difference between perfection and "Statistical Literacy Among Doctors Now Lower Than Chance"[1]. I don't think their intentions are bad, but they are woefully incompetent at many basic things.
As it happens, the daily practice of medicine does not require interpretation of p-values. Indeed, medicine existed before the p-value.
The people who create studies that ultimately guide policy decisions are specialized (much like people who write GPU drivers are different from those who run inference)
> As it happens, the daily practice of medicine does not require interpretation of p-values. Indeed, medicine existed before the p-value.
What are you talking about? Doctors refer people based on test results every single day. From what I've seen, hardly any of them understand the precision/recall of the tests that they then use to refer you (or not) to screening procedures (which are not all harmless).
What are you talking about? How is a single lab value going to generate a p-value? Why are you presuming that your family med doc should be calculating an ROC for each of her 1,500 patients?
The selection of lab critical values is performed by experts in clinical pathology. Exactly the people who were not included in the paper you cited.
You can find links to support any argument you want on the internet.
To place this in clearer HN terms, you're saying that a front end dev is trash because he didn't write his own web browser in assembly.
I can only presume that they got the atomic symbol for potassium (K) mixed up with vitamin K. That’s so wrong it crosses over into being “not even wrong” but entirely wrong and beside the point. I hope they aren’t your doctor anymore, or anyone’s. Please tell me you reported this incident to the state medical board.
The data until recently suggested that, so thats the risk you take. Would you rather be living in ancient greece and shoved full of hemlock leaves for arthritis? Or have a 19th century surgeon remove your appendix?
There's risk in life and odds-wise if you're in the developed West, you're going to get care and medicine that will greatly prolong your life.
Also this paper is super vague. What percent of people even get this? How long does it last? They havent even done a study to see how long it lasts yet. I have a feeling this isnt going to be our generation's asbestos or thalidomide.
That being said, you should decide your own risk profile. If MRI gives you concerns there are alternatives that dont involve contrast.
But given our track record, a little humility would go along way.
When a highly educated doctor tells you that something is safe, a person is going to assume that means that someone somewhere has proven that the substance is safe. If what they really mean is that no one really knows, but so far, no experiments have been able to prove danger, then we should say that instead.
> When a highly educated doctor tells you that something is safe, a person is going to assume that means that someone somewhere has proven that the substance is safe.
Contrast agent has been widely studied and determined to be reasonably safe. You’re not going to be administered any routine procedures or compounds that are known to be dangerous without an examination of the risks and benefits.
> If what they really mean is that no one really knows, but so far, no experiments have been able to prove danger, then we should say that instead.
“No experiments have been able to prove danger” is too generic to be usefully different than saying that it’s understood to be reasonably safe.
Even this paper isn’t saying that contrast agent is bad or dangerous in general. It’s exploring a potential effect that we can now detect and study.
Exactly...it's also not reasonable to be asked to prove a negative. "Prove it's safe" (equivalent to "prove there isn't any danger") is "prove there isn't a teapot orbiting Venus" territory.
Every procedure has some negligible risk, and doctors are trained to mitigate major risks to peoples' health with screenings, medications and surgeries that are of lesser risk than the alternative of inaction. "Safe" is a reasonable explanation for the vast majority of laymen they have to communicate with.
My point is not that you must prove it safe. My point is that it is dangerous to communicate to people that something is safe, and simply assume that they understand that negatives can’t be proven, and you don’t literally mean that someone has proven it to be safe.
This is pretty much how we get into the territory of "this product may contain peanuts" even if it has never even been near peanuts, but that warning is need because if in the offcase it has touched peanuts the company can't be sued. But this makes pretty much every other warning worthless.
We shouldn't have to clarify that everything is only 99.999% safe and assume that everything carries some form of risk even if small.
By that standards everything we do is unsafe. Every single activity we do carry some neglible risk. Explaining all of these would be lot more trouble than value in general.
By that definition there is literally no substance in existence that has been proven safe. Because the definition of safe is that no experiments have been able to demonstrate danger.
You know that you can’t prove a negative.
I know that you can’t prove a negative.
Probably most people on HN know that you can’t prove a negative.
But when a person who doesn’t spend their time nerding out on science goes to the doctor and hears, “the substance is safe”, it is not a guarantee that they know that you can’t prove a negative. If you can’t be sure that your audience knows that it’s not possible to prove a negative, then you should be pretty cautious with your words.
Safe, in the context of living on Earth, means an acceptably low risk of a bad outcome.
Tylenol is safe. Tylenol can also permanently damage your kidneys.
Walking is safe. Walking can also permanently damage your cartilage.
Food is safe. Thousands of people die from choking.
We all know this, colloquially. When it comes to medicine, it is as if one's brain hops and skips right out of their ear. It's not magic, it works like everything else on Earth works.
I think there is a non-insignificant number of people who would understand the word safe as no risk, who if something bad happened to them after submitting themselves to such a safe procedure, would find themselves deceived. Technically, I think they would be correct. Therefore, it should be explained that there is a risk but that it is on some order that they can relate to, like the risk of walking down the street.
Which is strong evidence that the danger is very small, very rare, or takes a very long time to develop.
You don't need a large clinical trial to prove that being shot in the head is harmful; you do need a very large trial to detect that, say, a drug increases the risk of cardiovascular disease by 4% in a specific sub-population.
Yes, exactly, but that is the definition that people who are not doctors are going to use when doctors tell them that something is safe. So we shouldn’t do that.
There is nothing mathematically 100% safe, the human meaning of the word inherently involves some kind of uncertainty.
Going for a test itself via car has a quite significant risk itself, should the doctor say that you shouldn't move out of this room, it's not safe?
Like even regularly used medicine has some slight chance of an adverse reaction, that's how minuscule side effects multiplied to human population times the number it's taken results in.
Guess what often has many orders of magnitude greater risk? Continuing having the disease you went to the doctor with in the first place, or having it lie undiscovered.
Literally every single medical procedure, down to the most mundane, has risks.
That's why we don't give MRI's out the wazoo. We actually gatekeep them a lot, and most research will tell you that investigative MRIs without chief complaints are a bad idea and we don't do them.
I had cancer. I had no MRIs, but multiple CT and PET scans. CT scans and PET scans have risk - they don't just do those for kicks. But you know what else has risks? Cancer. So there's a calculus here.
Every single medical procedure, down to getting your blood drawn, has this calculus. Nothing is risk free.
The biggest risk is false findings for a lot of diagnostic procedures. A false finding may cause enormous psychological stress, but more importantly it usually causes further, more invasive testing, which may pose much higher risks than the original procedure did. It's real statistical risk, which individual patients emotionally often can't relate to. Eg. an MRI shows clear signs of a tumor, you consequently get an endoscopic biopsy through your stomach, or colon, and then happen to die from anesthesia, intestinal perforation, sepsis... The "tumor" turned out to be a cryptic but harmless extra intestinal loop. Sounds made up, but this sort of thing happens enough to make unnecessary diagnostic procedures more harmful than beneficial.
However, I do think the reason MRI aren't used more often is because they are fucking expensive to operate. They need to run more or less 24/7 to be economical, which means they are commonly not scheduled with slack for "optional" investigations.
Not sure, if that's a reasonable possibility, but it's kind of irrelevant, since I would still consider a detected benign tumor a true positive for an MRI scan.
Incorrect, there is risk associated with performing MRIs without chief complaints.
These types of MRIs often cause anxiety and can lead to riskier medical procedures that are not necessary. This is because imaging is actually not perfect. There is always a risk you see something there that is not a big deal, or that you misinterpret the image. That potentially means unnecessary surgery or medicine. That can kill you.
That's why if you go to any doctor in the US and say "I want an MRI, no, nothing is currently wrong with me" they won't do it.
I do not buy this argument. The error would be in misinterpreting the image and taking the unnecessary treatment, not in doing the test in the first place. How is there any benefit in having less information?
In medicine, there is obviously a benefit in having less data. If I told you that you have a vein in your brain that could aneurysm at any point and instantly kill you, but no, we can't do anything about that - would that help you?
No, that would exclusively make your life worse, at least for the vast majority of people. It's also true for a lot of people. It could be true for you, right now.
Also, just because the error is in interpreting DOES NOT mean that the MRI is somehow magically off the hook. The risk came from the MRI. If you never did the MRI, then it would be impossible for that scenario to happen. That's just plainly true.
So therefore, if you do the MRI, there is a risk of that happening. Taking that risk without any complaints is deemed not worth it, so we don't do it.
> I do not buy this argument. The error would be in misinterpreting the image and taking the unnecessary treatment, not in doing the test in the first place. How is there any benefit in having less information?
There is no 'perfect information' but instead there is noise with every signal. It feels like that shouldn't be true ('the picture shows exactly what is happening, right?') but there are several levels at which the 'truth' that is assessed in an MRI can be degraded that have nothing to do with misinterpretation.
Even 'misinterpretation' is tricky - if something is only sometimes going to cause a clinically bad outcome, commenting or not commenting isn't a question of interpretation but of personal practice standards.
Around 10 years ago, I had an brain MRI with contrast. I specifically googled it and found a paper saying it builds up in the brain. I asked the MRI specialist about it, she was surprised I knew this and said she was familiar with the research. She mentioned that her professor also knew about it, but that the paper had other motivations, some conflict of interest, and that I shouldn't be worried. FFS.
Contrast isn't always necessary. Am not a doctor, but I have MS and get them regularly.
I've only had a couple with contrast. My understanding is that contrast highlights abnormal stuff and some tissue sorts more than without contrast. Specifically, they use it in MS to get a better look at an active lesion in the brain. You can still see the lesion without the contrast, though, so most of the MRIs are taken without contrast and then another with contrast if necessary. They have known about various side effects of contrast for some years (allergies, etc).