4 ms·

The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something o

The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something off. But you can‘t really reschedule everybody constantly, as that would entirely break the concept.

cyberax 8mo ago
"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper. So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much. Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
- tptacek 8mo ago
  I think you're missing the point. The psychological cost of a conditional-positive result is nonzero, and can be very significant (I speak from a little bit of experience here). But far more importantly: the physiological cost of invasive followups when you eventually trip the threshold of "time to go explore with a scalpel" is very high, and the missing evidence this story is about is whether you can get to that threshold with an MRI. Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
  - lostlogin 8mo ago
    This is pretty much what the experts say: https://www.ranzcr.com/college/document-library/2024-position-statement-on-whole-body-mri https://www.ranzcr.com/college/document-library/2024-positio...
  - cyberax 8mo ago
    > Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures. Again, _all_ you need to do is to make a follow-up scan in 1-3 months to see if there are any changes. It's a preventative tool, so unless you have other indications, it's almost always safe to wait for a bit. And yes, it requires educating patients that sometimes just waiting and doing a follow-up scan is right. And yes, I also have a personal experience with that (I had an "idiopathic lymphadenopathy", aka "we don't know WTF is going on").
    - amanaplanacanal 8mo ago
      It's a good thought experiment, but what you really need here is a randomized controlled study to see if your new plan results in better outcomes, before you roll it out to the whole world.
    - tptacek 8mo ago
      * Doctors and medical researchers keep saying that routine MRIs for non-symptomatic or low-risk patients is a bad idea, because the outcomes are worse than not scanning. * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy. * Nevertheless, here we are, nerds arguing we know better than all these people.
      - cyberax 8mo ago
        And I don't buy that. EXACTLY this was also said about prostate cancer screening. Word-for-word. "Overdiagnosing", "people are better off not knowing", "psychological burdens", "invasive procedures", etc. Now we have multiple longitudinal studies of people receiving aggressive screening and the usual standard of care. The aggressive screening group, unsurprisingly, has better outcomes with less mortality. > * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy. Yeah. I guess it's time to stop using fire alarms. People are better off not knowing if a building is on fire, and frequent false alarms have a negative effect on psychological well-being. Just look at the risk of burning to death. Alarms make no sense at all! > * Nevertheless, here we are, nerds arguing we know better than all these people. Yes. Absolutely. And I actually have read (I think) all the studies, and came thoroughly unimpressed. They're utterly sloppy with poor statistical analyses. It's absolutely an indictment of the medical industry that has become so crusty that it can't be bothered to integrate new diagnostic modality. That is the _only_ way to detect multiple lethal cancers while they are still curable.
        tptacek 8mo ago
        You're not engaging with the logic. Stipulate that it is the only way to detect multiple lethal cancers. If you end up harming more people than you help, the intervention is bad. Right now, you're only looking at one half of the balance sheet.
- jmward01 8mo ago
  I totally agree. US healthcare is broken and costs aren't tied to the reality of how expensive something actually is. I have very high hopes that modern medicine is in for a massive disruptive change where things like full body MRI, along with analysis, could be done very cheap and with no admin overhead. In that model 'we see something we aren't sure of. It is probably nothing but to be sure we want to do follow-ups' is far less of a problem. A lot of this however is how it is discussed with the patient. Discussions about the likelihood of there being a real issue when something is seen need to be clear and informative without being alarming. 'We did a routine scan and these often show transient artifacts that turn out to be nothing, but in an abundance of caution we want to do a followup' is totally different than 'we saw something we are concerned about and need to do a followup'. How things are messaged really matters.
- lostlogin 8mo ago
  > MRIs are extremely scarce tools of last resort and treat them like we treat blood tests. How would this work? I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2. I can also do an MR scan. It took a fair bit of training and the scanner and scan room cost about US$2 million. Service contracts on the scanner, scan room, chillers and required staffing utterly dwarf the cost of the scanner over its lifetime. The scan takes 20-75 minutes. Then the images get sent for reporting. Unlike a blood test, reporting isn’t automated. Even if it was, how could availability of MR ever be similar to a blood test?
  - cyberax 8mo ago
    > I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2. This depends on a blood test. Bacteria cultures or PCR tests still take more time. A mid-range scanner costs $500k, the room itself indeed might cost more. Just as real estate. Scanners are just not scarce anymore, there are even sites that sell used ones: https://prizmedimaging.com/collections/mri-equipment https://prizmedimaging.com/collections/mri-equipment (I now want one in my backyard...) You can lease a new top-level device at around $30k per month: https://www.meridianleasing.com/equipment/medical/mri-machines/siemens-magnetom-skyra-3-0t https://www.meridianleasing.com/equipment/medical/mri-machin... So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible. A full-body scan is about 1 hour. But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes. So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session. This is literally in the "blood test" expenses range. > Unlike a blood test, reporting isn’t automated. Radiology readings is one thing where AI is already making inroads. And radiologists can be located anywhere, it's a perfectly remotable job. > Even if it was, how could availability of MR ever be similar to a blood test? Yeah, indeed. How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building? Mass production happened. And this time it has taken the industry completely by surprise.
    - 8mo ago

cyberax 8mo ago

"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper. So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much. Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.

tptacek 8mo ago
I think you're missing the point. The psychological cost of a conditional-positive result is nonzero, and can be very significant (I speak from a little bit of experience here). But far more importantly: the physiological cost of invasive followups when you eventually trip the threshold of "time to go explore with a scalpel" is very high, and the missing evidence this story is about is whether you can get to that threshold with an MRI. Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures.
- lostlogin 8mo ago
  This is pretty much what the experts say: https://www.ranzcr.com/college/document-library/2024-position-statement-on-whole-body-mri https://www.ranzcr.com/college/document-library/2024-positio...
- cyberax 8mo ago
  > Treating MRIs the way we treat blood tests would almost certainly result in huge numbers of needless invasive procedures. Again, _all_ you need to do is to make a follow-up scan in 1-3 months to see if there are any changes. It's a preventative tool, so unless you have other indications, it's almost always safe to wait for a bit. And yes, it requires educating patients that sometimes just waiting and doing a follow-up scan is right. And yes, I also have a personal experience with that (I had an "idiopathic lymphadenopathy", aka "we don't know WTF is going on").
  - amanaplanacanal 8mo ago
    It's a good thought experiment, but what you really need here is a randomized controlled study to see if your new plan results in better outcomes, before you roll it out to the whole world.
  - tptacek 8mo ago
    * Doctors and medical researchers keep saying that routine MRIs for non-symptomatic or low-risk patients is a bad idea, because the outcomes are worse than not scanning. * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy. * Nevertheless, here we are, nerds arguing we know better than all these people.
    - cyberax 8mo ago
      And I don't buy that. EXACTLY this was also said about prostate cancer screening. Word-for-word. "Overdiagnosing", "people are better off not knowing", "psychological burdens", "invasive procedures", etc. Now we have multiple longitudinal studies of people receiving aggressive screening and the usual standard of care. The aggressive screening group, unsurprisingly, has better outcomes with less mortality. > * There's several clear, understandable mechanistic reasons why this would be the case, including simple applications of the base rate fallacy. Yeah. I guess it's time to stop using fire alarms. People are better off not knowing if a building is on fire, and frequent false alarms have a negative effect on psychological well-being. Just look at the risk of burning to death. Alarms make no sense at all! > * Nevertheless, here we are, nerds arguing we know better than all these people. Yes. Absolutely. And I actually have read (I think) all the studies, and came thoroughly unimpressed. They're utterly sloppy with poor statistical analyses. It's absolutely an indictment of the medical industry that has become so crusty that it can't be bothered to integrate new diagnostic modality. That is the _only_ way to detect multiple lethal cancers while they are still curable.
      - tptacek 8mo ago
        You're not engaging with the logic. Stipulate that it is the only way to detect multiple lethal cancers. If you end up harming more people than you help, the intervention is bad. Right now, you're only looking at one half of the balance sheet.
jmward01 8mo ago
I totally agree. US healthcare is broken and costs aren't tied to the reality of how expensive something actually is. I have very high hopes that modern medicine is in for a massive disruptive change where things like full body MRI, along with analysis, could be done very cheap and with no admin overhead. In that model 'we see something we aren't sure of. It is probably nothing but to be sure we want to do follow-ups' is far less of a problem. A lot of this however is how it is discussed with the patient. Discussions about the likelihood of there being a real issue when something is seen need to be clear and informative without being alarming. 'We did a routine scan and these often show transient artifacts that turn out to be nothing, but in an abundance of caution we want to do a followup' is totally different than 'we saw something we are concerned about and need to do a followup'. How things are messaged really matters.
lostlogin 8mo ago
> MRIs are extremely scarce tools of last resort and treat them like we treat blood tests. How would this work? I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2. I can also do an MR scan. It took a fair bit of training and the scanner and scan room cost about US$2 million. Service contracts on the scanner, scan room, chillers and required staffing utterly dwarf the cost of the scanner over its lifetime. The scan takes 20-75 minutes. Then the images get sent for reporting. Unlike a blood test, reporting isn’t automated. Even if it was, how could availability of MR ever be similar to a blood test?
- cyberax 8mo ago
  > I can do a blood test and send it to the lab to be processed in ~5 minutes from the moment I meet the patient. Consumable costs are about $2. This depends on a blood test. Bacteria cultures or PCR tests still take more time. A mid-range scanner costs $500k, the room itself indeed might cost more. Just as real estate. Scanners are just not scarce anymore, there are even sites that sell used ones: https://prizmedimaging.com/collections/mri-equipment https://prizmedimaging.com/collections/mri-equipment (I now want one in my backyard...) You can lease a new top-level device at around $30k per month: https://www.meridianleasing.com/equipment/medical/mri-machines/siemens-magnetom-skyra-3-0t https://www.meridianleasing.com/equipment/medical/mri-machin... So you're looking at maybe $1k a day that you need to pay towards the device cost. The consumables (helium) are pretty negligible. A full-body scan is about 1 hour. But for a follow-up you will need to focus only on a few areas, reducing that to maybe 20 minutes. So one device can feasibly do 10 primary scans a day and 20-30 follow-ups. So the cost of the device itself becomes on the order of $100 per imaging session. This is literally in the "blood test" expenses range. > Unlike a blood test, reporting isn’t automated. Radiology readings is one thing where AI is already making inroads. And radiologists can be located anywhere, it's a perfectly remotable job. > Even if it was, how could availability of MR ever be similar to a blood test? Yeah, indeed. How can we imagine that people will have computers on their _desks_ when even a small IBM takes half a building? Mass production happened. And this time it has taken the industry completely by surprise.
  - 8mo ago