
Portable MRI promises to provide immediate diagnosis in virtually any setting - chmaynard
https://news.yale.edu/2020/09/08/portable-mri-can-detect-brain-abnormalities-bedside
======
jmhmd
This is really cool technology, as a neuroradiologist anything that helps
decrease time/cost and increase availability of imaging is a big win.

It should be clarified, though, that this machine uses a very weak magnetic
field compared to traditional MRI, and while they are doing neat things to
improve image quality, the resolution of their images is still far, far
inferior to a standard 1.5 or 3 tesla magnet. This study does not compare to
traditional MRI, just shows that it is feasible to deploy in a real clinical
setting and that abnormalities can be detected. It should not be assumed that
this cheap and portable technology can replace standard MRI for most
indications.

That aside, I hope we get one at my hospital!

~~~
Scoundreller
I may be MRI ignorant, but even if the Teslas are lower, if the radius is
smaller (say, can only fit a head or arm or leg), does that make up for it?

I understand MRIs are largely a compromise. Organizations will buy only 1 or
2, and therefore buy one that will fit all but the most obese patients, to the
imaging detriment of anyone/anything smaller. Or is that all wrong?

~~~
SimplyUnknown
No. More teslas are needed for more signal to improve the signal to noise
ratio. And there is a lot of noise with portable non-shielded MRI. The only
way to compensate for this is by having bigger voxels (3-5mm per voxel rather
than the standard 1-2mm), or repeat scans and perform averaging. The more
drastic way is to do funky image reconstruction with compressed sensing or
deep learning.

The wider bore does indeed come at a cost. You have more geometric distortion
and a less homogenous magnetic field at the edges of the bore. Also, you will
need stronger magnetic gradients to form image, causing more energy
disposition (i.e. Heating the patient) and higher probability of peripheral
nerve stimulation (PNS, involuntary muscle twitches due electric fields
induced in the nerve caused by MR gradients).

~~~
lostlogin
To add to this comment, use of strong gradients also slows down scanning When
you hit SAR limits. The SAR has to be brought down with pauses between scans,
reducing gradient amplitudes, reduced resolution or shorter echo trains. It’s
really painful.

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deegles
Here is the device if you want to see a picture of it:
[https://www.medicaldevice-network.com/projects/lucy-point-
of...](https://www.medicaldevice-network.com/projects/lucy-point-of-care-mri-
device/)

~~~
Mizza
This looks small enough that it might just be possible to keep it in an
ambulance, which would be an absolute game changer for treating stroke.

Stroke treatment medication must be taken IMMEDIATELY to avoid permanent brain
damage, but there is a chance that the medication will kill you depending on
the type of stroke, and the only way to find out what kind of stroke it is is
with MRI.

Being able to treat stroke before a patient is MRI'd in a hospital will be a
massive benefit for humanity.

~~~
epmaybe
I basically want to say the same thing as u/lostlogin said about CT for
determination of what stroke it is, but maybe add some details.

You're basically looking at ischemic vs hemorrhagic stroke. Ischemic stroke
can get tPA or thrombectomy (within a 4.5hr window based on current data).
We're a bit more limited with hemorrhagic stroke, but some surgeries are
successful (clipping, coil embolization, etc).

From most studies, the sensitivity of noncontrast head CT ruling out a
hemorrhagic stroke (most likely due to an aneurysmal hemorrhage) is around
98-99%.[1] These tests are _fast_ , take maybe 2-3 minutes, and the entire
hospital will move heaven and earth for a stroke alert.

Why is this important? Because you're essentially limited by transport to the
hospital. The MRI in ambulance will save you maybe 20-30 minutes at most. It
may help some, sure, but I don't think it would be as massive a benefit as you
would expect.

You could argue that we should be administering tPA en route to hospital, and
that can certainly be debated. I would say that the risks of tPA
administration are pretty high, and should be done while in a hospital to
manage any adverse effects such as hemorrhage. Maybe if we develop better
safer clot busting tools we could improve morbidity after stroke.

My vote would be to increase preventative care, so that people stop having as
many strokes. It would likely be more cost effective in the long run, but I'm
no economist.

P.S. your fun fact for the day is that hospitals generally lose money from
strokes and tPA administration. The real money is in procedures like
thrombectomy! And maybe live close to a stroke center if you're at high risk
(diabetes, hypertension, coaguable)

[1]
[https://www.ahajournals.org/doi/10.1161/STROKEAHA.115.011386](https://www.ahajournals.org/doi/10.1161/STROKEAHA.115.011386)

~~~
lawlessone
> increase preventative care, so that people stop having as many strokes.

How is that done?

~~~
epmaybe
Off the top of my head: Increase access to primary care Encourage behavioral
change in people that help prevent disease (stop smoking, or don't eat sugary
foods, etc) Increase treatment affordability for preventing disease Add on
cheap treatment options if patients fail the above (more aspirin, statin,
metformin, etc)

------
andrewnc
This makes me happy and sad. Happy because this is some amazing technology
that will have immense benefits.

Sad for a selfish reason. I spent several years working to make a portable MRI
device and ultimately failed. I do wish it had worked in our lab, but am
extremely happy to see it working for humanity.

~~~
turbohz
Most people won't even try!

~~~
gibolt
Most people that try will fail. Fortunately, the more people that try, the
more likely one attempt will succeed.

~~~
polote
And the ones who succeed are usually just the luckiest

------
adwi
This is very cool.

I’m reminded of the work of Mary Lou Jepsen / Openwater, who have been
attempting to leverage commodity consumer imaging technology and machine
learning to create personal MRI-like 3D imagers orders of magnitude less
expensive and more accurate.

This is all the current information I’ve been able to find on the project,
looking forward to seeing how it progresses:

[https://www.openwater.cc/technology](https://www.openwater.cc/technology)

~~~
spacecity1971
Her tech is very promising. They have apparently undergone initial FDA
certification for device classification, so I’m also very curious to see how
they progress.

------
kveykva
My partner's sister could've potentially been saved if this existed already.
They could've moved the MRI to her instead of needing to move her to the MRI,
which couldn't be done. It's difficult seeing technology that could help save
someone's life come out after its too late. I hope this becomes widely
available and it saves lives.

------
car
The man behind this and other fascinating technologies is Jonathan Rothberg, a
modern day Leonardo.

[https://www.jonathanrothberg.com](https://www.jonathanrothberg.com)

~~~
keenmaster
I found it interesting that his parents founded Laticrete (according to
Wikipedia), a well-known construction material company. He was born into a
family that quite literally builds things.

------
benzible
Great story about Jonathan Rothberg's current project, creating a rapid at-
home COVID-19 test: [https://www.newyorker.com/tech/annals-of-
technology/jonathan...](https://www.newyorker.com/tech/annals-of-
technology/jonathan-rothbergs-race-to-invent-the-ultimate-rapid-at-home-
covid-19-test) (or
[https://beta.trimread.com/articles/37232](https://beta.trimread.com/articles/37232))

------
blakesterz
"Clinicians operating in areas outside of major metropolitan areas need rapid
diagnostic imaging results especially in cases of stroke, which requires
immediate treatment to prevent death or poor outcomes for patients. For
instance, the portable device could be used by doctors in poor countries,
rural areas, or even in ambulances to differentiate between stroke symptoms
caused by a brain bleed or blood clot. "

Sounds pretty neat. I wonder why this is only a brain thing, something about
size constraints maybe? I have no idea how these things might work. Can they
make a mini-mri for the rest of the body?

~~~
doctoring
MRI has a pretty unique value proposition for the brain, as it can detect and
discern things that other modalities (CT, US) simply cannot. Even a poor
quality MRI (essentially what this is) provides more information within the
brain than a high resolution CT. Many of the brain pathologies are also very
time-sensitive. So a good place to start.

Elsewhere in the body, MRI is less useful, and isn't really a workhorse as it
is with neuroimaging. (Except maybe joint imaging.) Most emergent problems are
detectable via those other cheaper, faster, & less onerous technologies.

Your guess about size is also likely correct; the positioning of the
antenna/coils and relation to the magnet are very important (especially with a
weak magnet) and much more challenging/variable if you're thinking about the
range of abdomen sizes (for example) versus head sizes.

~~~
toomuchtodo
Do MRIs have any value in replacing physical examinations (prostate,
colonoscopy) with diagnostic imaging? My understanding is that assay testing
is getting better, but still no replacement for the physical procedures I
mentioned.

~~~
jrowley
For measuring spread of disease like prostate cancer imaging can be really
helpful, see: PSMA PET-CT. I could imagine a world where imaging is really
cheap and agents were safer, in which case we might opt to use imaging instead
of physical exams, as they would offer way earlier detection. But for now the
additional radiation (not present in MR), cost, risk, time, etc makes it a no
go for standard of care screening.

------
transfire
GM adverted a hand held MRI years ago. Where is it?

I fear perverse economic incentives are holding the industry back. Case in
point, the X-Prize funded medical tricorder. Amazing work was done by many
teams, but we see no end product because the FDA over regulates (to support
entrenched business interests).

~~~
tgflynn
I was high school age in the early 80's when MRI machines were first getting
deployed and I was very interested in the technology back then. I remember
reading books/articles that claimed that within a few years there would be in-
vivo NMR machines in doctors offices which would replace many blood tests.
I've often wondered why that future never materialized. Is there some major
technical obstacle that wasn't understood then, did the economics turn out
against it or is there some other reason ?

------
josefrichter
Now this is the stuff we all should be working on, instead of chasing yet
another billion dollar photo sharing app

------
httpsterio
Looking at the pictures and I can't be anything but glad and hopeful. Having
recently gone through (as in, last Friday) a head MRI scan, the process
definitely leaves for something to be desired for.

I don't suffer from claustrophobia normally, but being stuck in that long
tunnel for half an hour really did a number on me. The head coil was a bit too
snug and pressed on my chin making it harder and harder to swallow and panic
started to set in halfway through. If it was just my head in a device (with
clear sides nonetheless!) I would've been a-okay for longer times as well, but
being in that tunnel with only my soles peaking out of it, I had a very real
fear of choking and/or getting stuck.

Sometimes modern medicine feels very brutal and scary and it takes a toll on
my mental wellbeing. I've put off on getting my gastroscopy for a few years
now because again, I don't exactly enjoy feeling like I'm choking and dying.

Anyways, this was just a tangent. Keeping my fingers crossed that I have a
tumor in my pituary, would be the best thing to discover in my situation. I'll
find out on Friday!

~~~
Luc
I could breathe normally during my gastroscopy. No pain though it felt
strange. The MRI was a lot more taxing mentally, and I had some of the same
issues as you. Best of luck.

------
hinkley
Did I miss something, or are they talking about this and not showing a picture
of it?

Two clicks farther in to get to:
[https://www.hyperfine.io/](https://www.hyperfine.io/)

------
gwillen
For the curious who want more information, I found a paper discussing the
general issues involved in "low-field" MRI:

[https://onlinelibrary.wiley.com/doi/full/10.1002/jmri.26637](https://onlinelibrary.wiley.com/doi/full/10.1002/jmri.26637)

For their purposes, "low-field" goes down to 0.25T, which is still somewhat
higher than the machine linked here, but they extrapolate values of some of
the parameters all the way down to 0. (And it seems like the general
principles are mostly the same.)

~~~
SimplyUnknown
There is some renewed interest in low field scanners. Past four decades have
mainly been pushing for higher fields to improve SNR. But low field has a few
advantages:

\- no need for superconducting magnets. This is a big win for developing
countries and portable systems.

\- better geometric accuracy. While not an show stopper as it can be corrected
for, but low field exhibits better geometric accuracy as you move away from
isocenter, which is of extra concern with e.g. radiotherapy applications.

\- more patient comfort as lower field strengths need less strong gradients
thus less chance for PNS (involuntary muscle twitches due electric fields
induced in the nerves)

------
ngcc_hk
Can ultrasound do brain scanning ... we cannot do mri of everything due to
cost and hard to arrange (even ct scan I were told is much easier to arrange
but I stick to the ultrasound vs mri). but we do ultrasound more frequently.
If that help, that helps.

When people are hunger As cannot afford food to tell them meat can also be
food may not make sense.

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chmaynard
I posted this article. You might have noticed that I made some minor changes
to the title before I posted it to HN. I believe this improved the likelihood
that it would be read by others on HN a tiny bit. I encourage others to do a
little creative editing of titles, but only if it improves the titles of their
posts in some way.

------
computerphage
If you're interested to learn more about how MRI works. I recently found an
excellent video on the topic. It's 42 min and quite technical, but that's what
I like about it.

[https://www.youtube.com/watch?v=TQegSF4ZiIQ](https://www.youtube.com/watch?v=TQegSF4ZiIQ)

------
Wagmire
Awesome awesome awesome! Medical advancements here will be fantastic.

We perhaps need to be preocupied with some ethical delimmas in the near future
[https://www.youtube.com/watch?v=Ecvv-
EvOj8M](https://www.youtube.com/watch?v=Ecvv-EvOj8M)

------
swiley
Isn't the resolution on these governed by the magnetic field strength (like
the nuclear spectrometers in chemistry?) That's why MRI machines are so big;
the magnets are insane (and (edit)[involve] a bizarre material: liquid
helium!)

~~~
andrewnc
Yes, but that's mainly because they use FFT for reconstruction. So you need
extremely clean data.

If, however, you use some significantly more sophisticated signal processing,
you can side step this requirement.

~~~
abrichr
Like what?

~~~
layoutIfNeeded
Maybe
[https://en.wikipedia.org/wiki/Compressed_sensing](https://en.wikipedia.org/wiki/Compressed_sensing)
?

------
agumonkey
Man would I had that 8 years ago I could have fed neuroscientists a decade
worth of data.

