3 ms·

> "Functional magnetic resonance imaging has transformed medicine." This is not even close to true. The clinical impact of fMRI is very constrained. I've met

by ska 6y ago

> "Functional magnetic resonance imaging has transformed medicine." This is not even close to true. The clinical impact of fMRI is very constrained. I've met many clinicians who have completely written it off at this point. Others that remain interested but find it mostly impractical and error prone. The only people I've met who seem to have any significant investment in it as a technology are cognitive scientists, and that's a ways from medicine. > It allows non-invasive mapping of a patient’s brain regions to enable more accurate, precise neurosurgery,1" Approximately nobody does this. fMRI isn't really even on the radar for most neurosurgeons. It's only recently that even detailed structural information (e.g. DTI) has got some real traction, let alone functional info. Note commercial vendors have had clinical packages on the scanners for (nearly? I forget who shipped DWI stuff first) a couple decades now. No such thing exists for fMRI, at minimum you need to buy a 3rd party processing system and may need a research key on your scanner. Some researchers are interested in this; that's a long way from transforming anything. > " as well as validating pharmacological effects of potential drugs on human brains.2" There is perhaps a bit more promise here, but it's still way into the research only end. In the 15 years since the referenced paper was published, not much of this "promise" has been realized as far as I know (but this is further from my wheelhouse)

astrange 6y ago
What is a research key? I'm imagining a license dongle.
- ska 6y ago
  Basically yes, a license package.
mountainriver 6y ago
I was just reading about them using fMRI in conjunction with high frequency focused ultrasound to lesion parts of the brain associated with certain mental disorders such as OCD. They seemed to be having decent success with that
- ska 6y ago
  Sure, there is research all over the place - but HIFU also hasn’t made a real impact clinically, maybe it will in future. Most of this stuff gets interest in papers for a few years , turns out to be impractical for whatever reason and dies on the vine. That’s ok, it’s worth trying .
unsrsly 6y ago
> Approximately nobody does this. fMRI isn't really even on the radar for most neurosurgeons. Except at basically any academic neurosurgery center? https://thejns.org/focus/view/journals/neurosurg-focus/48/2/article-pE11.xml https://thejns.org/focus/view/journals/neurosurg-focus/48/2/...
- ska 6y ago
  I thought I was clearer, apologies. People doing related research are interested in it, and a few teaching hospitals etc., but that’s a really small fraction. it’s not really a factor in most clinical practice. Thus “transformed medicine” is more than a bit of a stretch.
  - lostlogin 6y ago
    > it’s not really a factor in most clinical practice. For a nice anecdata point - I’m an MR technologist and clinically I’ve seen it done once, I’ve done it once and I’ve heard a colleague mention doing one. I’ve done them as research scans a hell of a lot of times.
  - unsrsly 6y ago
    fMRI is used to plan procedures that put eloquent cortex at risk. For example, tumor resections. Typically, fMRI is used for initial planning (whether the tumor is in the dominant hemisphere, how to approach the tumor). Then, in the actual surgery, function is confirmed using awake cortical mapping (e.g. stimulating different cortical areas with a bipolar electrode while the patient performs language tasks). See more: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966674/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966674/
    - ska 6y ago
      > Typically, fMRI is used for initial planning No, it is not. In my experience it is at best rarely used for planning, i.e. typically planning is done without fMRI. It will probably have DWI but maybe not tensor information (although that is growing). Awake cortical mapping and/or task based references are very typical (near 1/2 of procedures, iirc). fMRI is not. I'm not saying it's a bad idea or anything. I have a pretty good understanding of all the tradeoffs for fMRI but I'm not arguing for or against it. I'm reacting to the claim that is commonly deployed in clinical (not research) practice, which just doesn't match my (fairly extensive) experience. So the articles claims of "transforming medicine" are aspirational. source: Have worked directly in this market (clinical), hashed this out with many neurosurgeons,seen the procedures, etc. See also MR tech comment in this thread, in my experience very typical.
scotty79 6y ago
My SO had fMRI done before her first brain surgery for glioma that was located near speech center and motor cortex. It wasn't a big deal, so I think they apply it routinely in some cases in their practice. I'm not sure if they got much from it because it was really low res in comparison with standard MRI. Although she made a full recovery after that surgery.
- ska 6y ago
  That’s interesting! You are right the resolution (both spatial and temporal) and accurately coregistering (and then with surgery, brain shift) can be among the limiting factors for clinical use. Plus the difficult in getting good signal. I suspect this has more to do with where they had it done than anything else. There are neurosurgeons who champion it for sure , but not that many. Most places aren’t set up for it at all from what I’ve seen. I'm guessing her procedure wasnt' done awake, was it? This is a very common way to deal with the functional stuff especially near speech or motor. Glad to hear she had a good outcome!
  - unsrsly 6y ago
    Awake cortical mapping has much better resolution than fMRI, and it avoids image registration issues, but it requires a great deal of planning and patient motivation. If it turns out that the language center is on the opposite side from the area of the surgery, then awake mapping might not even be necessary. This is why fMRI is often used as a planning step before awake cortical mapping during the actual surgery.
    - ska 6y ago
      > why fMRI is often used as a planning step It really isn't - see my other comment. The other thing to consider here is unintentional media bias - when a lay publication wants information they tend to go to tier 1 research & academic institutions; exactly the sort of place that has all the latest new toys. This is often very far from typical practice. So people outside of healthcare hear about all sort of things that are a decade or more from general usage, even if they get there eventually. From the outside, it's probably difficult to understand how conservative medicine is generally. Even effective new practices often take decades to become really mainstream.
unsrsly 6y ago
> No such thing exists for fMRI, at minimum you need to buy a 3rd party processing system and may need a research key on your scanner. This is not the case, for example see the GE BrainWave software. https://www.gehealthcare.com/products/advanced-visualization/all-applications/brainwave https://www.gehealthcare.com/products/advanced-visualization...
- ska 6y ago
  Oh that's a good point, I should have been more clear (and honestly had forgotten BrainWave, you can option that with their DTI fibre stuff). These systems are still not on the scanner (unless some of the latest acquisition stations support it? Still not on most of the deployed stuff) so typically another workstation is needed at least, this package does happens to be from the vendor. For anyone reading who finds this confusing, you can license on the machine the ability to do the "pulse sequences" you need, but it only handles the raw data - you typically need another step to process that into images you can use. Otoh most of the people I know doing this on GE scanners used something else, but that could easily be sampling bias.

by ska 6y ago

astrange 6y ago

What is a research key? I'm imagining a license dongle.

ska 6y ago
Basically yes, a license package.

mountainriver 6y ago

I was just reading about them using fMRI in conjunction with high frequency focused ultrasound to lesion parts of the brain associated with certain mental disorders such as OCD. They seemed to be having decent success with that

ska 6y ago
Sure, there is research all over the place - but HIFU also hasn’t made a real impact clinically, maybe it will in future. Most of this stuff gets interest in papers for a few years , turns out to be impractical for whatever reason and dies on the vine. That’s ok, it’s worth trying .

unsrsly 6y ago

> Approximately nobody does this. fMRI isn't really even on the radar for most neurosurgeons. Except at basically any academic neurosurgery center? https://thejns.org/focus/view/journals/neurosurg-focus/48/2/article-pE11.xml https://thejns.org/focus/view/journals/neurosurg-focus/48/2/...

ska 6y ago
I thought I was clearer, apologies. People doing related research are interested in it, and a few teaching hospitals etc., but that’s a really small fraction. it’s not really a factor in most clinical practice. Thus “transformed medicine” is more than a bit of a stretch.
- lostlogin 6y ago
  > it’s not really a factor in most clinical practice. For a nice anecdata point - I’m an MR technologist and clinically I’ve seen it done once, I’ve done it once and I’ve heard a colleague mention doing one. I’ve done them as research scans a hell of a lot of times.
- unsrsly 6y ago
  fMRI is used to plan procedures that put eloquent cortex at risk. For example, tumor resections. Typically, fMRI is used for initial planning (whether the tumor is in the dominant hemisphere, how to approach the tumor). Then, in the actual surgery, function is confirmed using awake cortical mapping (e.g. stimulating different cortical areas with a bipolar electrode while the patient performs language tasks). See more: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966674/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966674/
  - ska 6y ago
    > Typically, fMRI is used for initial planning No, it is not. In my experience it is at best rarely used for planning, i.e. typically planning is done without fMRI. It will probably have DWI but maybe not tensor information (although that is growing). Awake cortical mapping and/or task based references are very typical (near 1/2 of procedures, iirc). fMRI is not. I'm not saying it's a bad idea or anything. I have a pretty good understanding of all the tradeoffs for fMRI but I'm not arguing for or against it. I'm reacting to the claim that is commonly deployed in clinical (not research) practice, which just doesn't match my (fairly extensive) experience. So the articles claims of "transforming medicine" are aspirational. source: Have worked directly in this market (clinical), hashed this out with many neurosurgeons,seen the procedures, etc. See also MR tech comment in this thread, in my experience very typical.

scotty79 6y ago

My SO had fMRI done before her first brain surgery for glioma that was located near speech center and motor cortex. It wasn't a big deal, so I think they apply it routinely in some cases in their practice. I'm not sure if they got much from it because it was really low res in comparison with standard MRI. Although she made a full recovery after that surgery.

ska 6y ago
That’s interesting! You are right the resolution (both spatial and temporal) and accurately coregistering (and then with surgery, brain shift) can be among the limiting factors for clinical use. Plus the difficult in getting good signal. I suspect this has more to do with where they had it done than anything else. There are neurosurgeons who champion it for sure , but not that many. Most places aren’t set up for it at all from what I’ve seen. I'm guessing her procedure wasnt' done awake, was it? This is a very common way to deal with the functional stuff especially near speech or motor. Glad to hear she had a good outcome!
- unsrsly 6y ago
  Awake cortical mapping has much better resolution than fMRI, and it avoids image registration issues, but it requires a great deal of planning and patient motivation. If it turns out that the language center is on the opposite side from the area of the surgery, then awake mapping might not even be necessary. This is why fMRI is often used as a planning step before awake cortical mapping during the actual surgery.
  - ska 6y ago
    > why fMRI is often used as a planning step It really isn't - see my other comment. The other thing to consider here is unintentional media bias - when a lay publication wants information they tend to go to tier 1 research & academic institutions; exactly the sort of place that has all the latest new toys. This is often very far from typical practice. So people outside of healthcare hear about all sort of things that are a decade or more from general usage, even if they get there eventually. From the outside, it's probably difficult to understand how conservative medicine is generally. Even effective new practices often take decades to become really mainstream.

unsrsly 6y ago

> No such thing exists for fMRI, at minimum you need to buy a 3rd party processing system and may need a research key on your scanner. This is not the case, for example see the GE BrainWave software. https://www.gehealthcare.com/products/advanced-visualization/all-applications/brainwave https://www.gehealthcare.com/products/advanced-visualization...

ska 6y ago
Oh that's a good point, I should have been more clear (and honestly had forgotten BrainWave, you can option that with their DTI fibre stuff). These systems are still not on the scanner (unless some of the latest acquisition stations support it? Still not on most of the deployed stuff) so typically another workstation is needed at least, this package does happens to be from the vendor. For anyone reading who finds this confusing, you can license on the machine the ability to do the "pulse sequences" you need, but it only handles the raw data - you typically need another step to process that into images you can use. Otoh most of the people I know doing this on GE scanners used something else, but that could easily be sampling bias.