Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A low-cost and shielding-free ultra-low-field brain MRI scanner

nature.com

Post reply on HN
Print view View original

141–150 of 151 posts

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#141

Post by akireu »

asiachick wrote: post #105
cute_boi wrote: post #21

Earlier quoted context omitted.

Yea, the way they turned the bleak situation into something sanguine is fascinating. I still remember how expensive is MRI. I used to earn like $150 usd and the cost was around $200 usd. I hope such inequality shall perish in the future, so people can at least get proper treatment.

I'm curious what makes them expensive. In Japan they are basically free (covered by national insurance for which the price is low). I believe at one point Japan had the most MRI machines per capita. I think the government just decided they were worth while and got a bunch where as in the USA they were seen as a money source and they generally charge $1k to $10k ?!?!?! I'd love for the expensive ones to be disrupted.…

I live in a Russian city of 100k people and there are at least 3 medical MRI machines nearby that I visited, of a total 8 offers that maybe share the machines (though likely not), all of them of 1T field strength or above. I can get a brain MRI this week for some $70, or a full-body MRI (the most expensive as per the price list) for $400. If anything, these services got some 30%-50% cheaper in the past decade. Barring some African hellhole, the argument to scarcity or expense of these machines is complete and utter bullshit. It's just that HN is America-centric, and American healthcare is a cesspit of waste and corruption.

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#143

Post by fluidcruft »

haldujai wrote: post #129
lostlogin wrote: post #115

Earlier quoted context omitted.

Maybe the state of play has changed, as we scan for this indication in MR, not PET. Have you a link to something as my understanding is that small lesions are better found with MR? Or is this a rule that applies to high end research work and hasn’t hit clinical practice yet? Maybe a limitation of the isotopes used clinically?

I am a radiologist. FDG PET/CT is not used to stage intracranial metastases due to background brain activity significantly reducing sensitivity. You’re likely only detecting lesions 1cm or greater in the brain, or ones which demonstrate low metabolic activity and appear dark. MRI is much more sensitive and specific and is the standard of care for staging in my practice and as per the NCCN clinical guidelines. I haven…

I probably wasn't clear in context because different meanings of sensitivity seem to have crossed paths. I was referring to the physics of signal detection in MRI vs PET, not clinical disease detection. MRI only detects signal from an extremely small fraction of the protons in the sample. You have no chance of detecting individual protons. MRI makes up for that with brute force of proton numbers in tissue.

Modalities like PET can detect events from a far greater fraction of the isotopes present. But they are limited in spatial resolution by the physics. This is why MRI is said to be a very insensitive modality.

See for example the discussion about MRI vs other modalities here:

https://wikipedia.org/wiki/Molecular_imaging

which notes that MRI has a sensitivity around 10^−3 to 10^−5 mol/L whereas PET is many orders of magnitude more sensitive at 10^-11 to 10^-12 mol/L.

So what I meant was if there's an analogy that you're looking at a skyscraper, MRI can "see" which which rooms have floodlights turned on. PET could detect whether there's a single candle burning somewhere in the building, but it can't tell you which room it's in.

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#144

Post by TaylorAlexander »

matheusmoreira wrote: post #98
TaylorAlexander wrote: post #75

Earlier quoted context omitted.

I obsess over this concept. I am a robotics engineer and my dream is local manufacturing with small DIY machines. But it's a lot of work! When I have a little more time I want to teach community robotics classes and build machines that makes shoes and hot food and other important goods, designed and built as a community. I designed a cheap large format laser cutter [1][2] and now I am designing shoes that can be made…

That is so cool. I wish you success.

Thank you!

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#145

Post by SubiculumCode »

datavirtue wrote: post #52
SubiculumCode wrote: post #48

Earlier quoted context omitted.

That's cheap...just not cheap enough for me to want to build it in my garage as a party gag.

I have seen people of modest means build cars that cost five times that in their garage. ...and that was twenty years ago.

No doubt, but they did it for love, not as a, "oh hey, you wanna get in my MRI" gag at a party :)

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#146

Post by queuebert »

fluidcruft wrote: post #95
queuebert wrote: post #70

Earlier quoted context omitted.

Or a massive brain hemorrhage.

That's generally been the challenge with these super low-field scanners--they can't get T2*/susceptibility that's anywhere close to useful (yet?).

That's an interesting point. I didn't realize they had that problem. You could probably see a bleed on a T1 contrast exam, though.

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#147

Post by jl2718 »

asiachick wrote: post #105
cute_boi wrote: post #21

Earlier quoted context omitted.

Yea, the way they turned the bleak situation into something sanguine is fascinating. I still remember how expensive is MRI. I used to earn like $150 usd and the cost was around $200 usd. I hope such inequality shall perish in the future, so people can at least get proper treatment.

I'm curious what makes them expensive. In Japan they are basically free (covered by national insurance for which the price is low). I believe at one point Japan had the most MRI machines per capita. I think the government just decided they were worth while and got a bunch where as in the USA they were seen as a money source and they generally charge $1k to $10k ?!?!?! I'd love for the expensive ones to be disrupted.…

They are $150k on Alibaba. A free market price for an MRI would be maybe $50.

Noninvasive diagnostics should not be regulated.

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#148

Post by thfuran »

a-dub wrote: post #5

woah. woah. woah. hold on a second here... are we comfortable enough with understanding all of the behavior of deep learning models to where we can confidently put them in the pipeline for diagnostic clinical imaging? i'm okay with using them for image analysis, but denoising and other image production tasks seems dangerous. how do you know what you're looking at is real as opposed to something that just looks convin…

What's the worst that could happen?

https://www.dkriesel.com/en/blog/2013/0802_xerox-workcentres...

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#149

Post by dimi_chip »

What is the SNR they are getting ? Can't seem to find this info in the paper. I am also working on a low-field MRi prototype, but at a much lower field (1mT) and using SQUID-based detection. This approach, in theory, allows to have much better T1 contrast, which is an issue raised in this paper. Also, at these levels of field you can use a low-consumption resistive magnet which permits much better field homogeneity. Anyway the results this team is getting are very impressive and gives me hope that portable MRI is not science fiction. Would love to see some clinical diagnosis data with a bigger sample and more doctors. Will definitely try out their EMI cancellation algorithm on my experiment !

Re: A low-cost and shielding-free ultra-low-field brain MRI scanner

#150

Post by TheMagicHorsey »

TaylorAlexander wrote: post #75
TheMagicHorsey wrote: post #72

Earlier quoted context omitted.

I wonder if its practical to DIY your own production line automation today with Arduino. Like if I had a simple product, could I buy stuff off the shelf and integrate it myself in my garage and end up with a little mini-factory? Exciting to think about.

I obsess over this concept. I am a robotics engineer and my dream is local manufacturing with small DIY machines. But it's a lot of work! When I have a little more time I want to teach community robotics classes and build machines that makes shoes and hot food and other important goods, designed and built as a community. I designed a cheap large format laser cutter [1][2] and now I am designing shoes that can be made…

Great concept!
Post reply on HN