Portable MRI promises to provide immediate diagnosis in virtually any setting
news.yale.edu
news.yale.edu
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!
It's not too shabby though, especially if you've looked at older MRI images enough.
I think part of their argument, at least implicitly, is that a lot of things don't necessarily need the resolution of standard MRI to be clinically useful, especially in places like ER settings.
My skepticism about papers like this with small Ns (maybe even some larger Ns) is how well they generalize to very unselected populations. It's sort of par for the course with early-stage medical products, even quality ones, but lots of times as the Ns increase and there's less control over the patient populations they're being used on, the patients become more heterogeneous, things don't work out quite as well.
Still good to see research in this area.
I'd have to look at the paper more closely but I wonder if this can be used for functional imaging as well.
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?
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).
To get a good high resolution signal you need field homogeneity (and/or accurate mapping), high quality gradients, and good SNR. Field strength helps with the last part.
There are other trade offs too, for example imaging artifacts due to implants (or even being able to image them), susceptibility, etc. vary with main field strength.
It always confused me that MRI did millimeter scale imaging with radio waves that are meters long. I learned, and other's might be interested to learn, the trick is that it's the magnetic gradient that does the imaging. Each nucleus in the volume is tagged to it's place along the magnetic gradient axis by the local magnetic field strength shifting the emission frequency proportionally. That frequency shift is then inverted back to position for that axis.
I did get bumped from my slot on a 3T MRI due to an emergency I a uk hospital recently due to some patients needing it more than me.
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.
> Using the portable MRI device, researchers from Yale found evidence of ischemic stroke, hemorrhagic stroke, subarachnoid hemorrhage, traumatic brain injury, and brain tumors in patients presenting with neurological symptoms at Yale New Haven Hospital.
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.ambulance.vic.gov.au/stroke-ambulance-continues-...
How is that done?
I come here just to say the same thing, it's a game changer for stroke treatment since for the ischemic stroke (most common type of stroke) every minute lost means millions of neurons loss in the brain that cannot be recovered.
Now there is a new procedure to "fish" and remove the blood clots that are blocking the blood vessels.
Anyone know the selling price for this portable MRI? I can see that it's not for any ambulance but definitely can be equipped for the special type of ambulance vehicles catering for the stroke treatment center.
However, this could be a interesting product for field hospitals used in disaster relief. It could also be of use at medical facilities in more rural areas, where the purchase and/or use of a conventional MRI may not be feasible.
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.
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:
Any one have any updates?
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?
There are other reasons an MR could be better though, for example no ionizing radiation, so you could argue you could send more patients through it than you would with an ER CT (you would only send patients you have a higher confidence of them requiring it to avoid spamming radiation).
The contrast is so good.
You are probably aware, but there are 5 minute protocols (Siemens call their one a “go brain”) that are pretty reasonable, and probably not far off a gold standard routine protocol 10 years ago.
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.
Prostate cancer screening in general is no longer officially recommended by the AAFP as a rule [1], but if a patient decides to opt-in to screening, the "assay" (PSA) is preferred over a digital rectal examination, which has been shown to be increasingly useless in the detection of prostate cancer. MRI doesn't currently have a role in prostate cancer screening, but Prostate MRI has an increasingly critical role in diagnosis.
CT colonography is currently a viable option for colon cancer screening instead of colonoscopy, though colonoscopy is still considered the gold standard.
Chest CT is currently recommended to screen for lung cancer in patient's that meet certain criteria (age, smoking history).
Mammography is obviously the workhorse of screening for breast cancer, rather than physical examination. But MRI is recommended as a screening mechanism for certain patient populations with very high risk of breast cancer (e.g. certain BRCA mutations). The small population, high prevalence, and benefit of early detection combine to make this a viable option.
[1] https://www.aafp.org/family-physician/patient-care/clinical-...
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).
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!
Two clicks farther in to get to: https://www.hyperfine.io/
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.)
- 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)
When people are hunger As cannot afford food to tell them meat can also be food may not make sense.
We perhaps need to be preocupied with some ethical delimmas in the near future https://www.youtube.com/watch?v=Ecvv-EvOj8M
If, however, you use some significantly more sophisticated signal processing, you can side step this requirement.
Worth noting: A lot of the focus on advanced signal processing has been focused on scan speed, and main field strength and homogeneity is only one factor in resolution. You need high quality gradients too, the finer the resolution the more precise everything has to be set up or you are just smearing the signal around in space.