FDA clears ‘world’s first’ portable, low-cost MRI
healthimaging.com
healthimaging.com
Background: I'm a doctor with 3 years experience in acute medicine. AMA
Clearing some MRI misconceptions: 1. It's indicated ASAP in specific emergencies and will change how we manage them. For acute ischaemic stroke, it detects patients within the recomended time window for thrombolysis. Simply, it shows the cellular swelling in the brain, gives an estimate of the onset and we decide the risk/benefits of dissolving the clot. Second use, for cauda equina syndrome. Again we're looking for acute CNS tissue damage, this time from spinal chord compression, and the change in management is emergency neurosurgery (good luck getting them out of bed without an MRI) For herpes encephalitis, MRI is debatable because you can start empiric treatment. But I've seen it done.
Another misconception for the first use scenario in stroke. The MRI sequences we're interested in only take 1-3min and CT doesn't help us. But in my experience the whole scan takes 2h to organize, so point of care MRI is a game changer. Every minute counts when you're saving brain tissue. And Lower definition with artifacts are acceptable because you're looking for gross changes in a critically unwell patient.
Bonus: A report from when I managed my first suspected stroke as a junior doctor.
"49yo lady day 1 post op for total knee replacement (elective admission). Commorbidities of hypertension, obesity and osteoarthritis. She was just started on apixaban and gabapentin as per protocol, when I was asked to see her for new onset upper limb bilateral tremor.
On examining her I found the symptoms had started 1h ago. She was presenting bilateral upper limb ataxia as well, reflexes were reduced on the left and there was numbness corresponding to C4 dermatome. At this point I was worried about acute stroke whithin the 4h window for thrombolysis. I discussed the case with the acute stroke consultant and examined the patient with him. We requested an MRI brain to assess for acute posterior circulation stroke, because he thought time of onset was unclear (as per WAKE-UP protocol). I acompanied the patient to neuroradiology services. The MRI sequences we were most interested was DWI and FLAIR which only took a few minutes. We quickly scanned through the images noting there were was no DWI-FlAir mismatched high intensity signal areas within the brain parenchyma. This allowed us to rule out acute ischaemic stroke.
6h later the symptoms subsided and I was satisfied they were due to an adverse reaction to gabapentin."
Another area would be pediatric imaging, where it could be useful as a first imaging, ruling out larger lesions, possibly lessening the need for CT and decreasing radiation exposure, especially in the group approximately 1-4 years, who often need sedation to lie sufficiently still inside the MRI. Although at my institution the physicists have developed a ‘fast MRI’ (70 seconds), that gives reasonable resolution and contrast (T1,T2,T2*,DWI), and which we will try to implement in the group of patients who come to ‘try’ the machine (before deciding whether they need sedation or not).
Also, the low field strength, 0.064T vs 1.5T or 3T, would most probably allow us to image patients with implants which are unsafe at normal clinical field strengths of 1.5 or 3T (would have to be verified though).
For people interested in low field imaging the group at Athinoula A Martinos Center for Biomedical Imaging at Harvard has a homepage at https://www.nmr.mgh.harvard.edu/lab/lfi
With such a device, do you need a Radiologist or other rare super specialist to actually read the images? Or can they be used by generalists?
Will this turn brain MRIs into a tool comparable to the X-Ray scanner my dentist uses or the Ultrasound used by the midwives a dozen times during pregnancy?
If so it looks like a game changer - something which will become a fixture in A&E departments everywhere.
Reasonably there are a plethora of indications and given that these machines will be installed at the point of care (A&E, ICU, etc) and supposedly are safe to use on basically all patients, one can imagine that it will be used very frequently. Though in this case the scan-time (30 min + change) could become a limiting factor (but, given it’s price, I guess you could just buy more machines). The image quality is of course not the same as with a modern clinical system but it is most certainly good enough for a preliminary test, and may very well decrease the number of patients sent for a ‘normal’ diagnostic scan (though the opposite may also be true, if you see something unexpected in the images, or if there are artefacts which are difficult to interpret). As with the ‘fast MRI’ I referenced to earlier, my current idea would be that it can be used as an initial screening, but, as always, if the test is normal, but the clinical suspicion persists one would have to continue with other tests.
Regarding whether the image should be read by a specialist or not, I am of course biased towards the specialist :) As I see it the main advantage of having the clinician interpreting the image is that they have ‘direct access’ to the patient, and can ask them specific questions based on the findings of the test. Though, time-utility wise it’s faster for a specialist to read a normal test. During med school I did a rotation at a primary care facility in the north of Sweden, in a municipality with 6000 inhabitants, located almost 2 hrs away from the closest hospital, the GP:s there read chest x-rays themselves at that time. Now the images are transferred digitally to the main hospital of the region and read by a radiologist. One can of course wonder whether it’s cost effective to train a large number of radiologists to read all the new studies which will be produced. My hope here is that computer aided diagnostic tools will increase the productivity of radiology specialists.
My experience from working together with neurosurgeons and neurologists who are very good at reading images in general, is that they anyway prefer to consult us for the interpretation, (they would rather operate than become specialist radiologists). In my opinion the professionals at risk of being side-stepped are the general radiologists, and I think this is already happening as telemedicine makes it possible for smaller hospitals to pay for specialist readings on a per study basis.
edit: regarding time utility, one would of course have to include the time it takes for the referring physician to write a request, and for the radiologist to write a report. And another advantage of having the clinicians read the image is that they have more information about the patient than they put in the request. So it’s also very possible that radiologists will not be consulted (depending on medicolegal circumstances and reimbursement systems etc.)
I'm actually doing what we call a taster in neuroradiology and it's been fascinating. Strongly considering applying for residency next year!
I did my elective at the PET center in Turku, great team. They even let me play with the rat MRI for Alzheimer's. They had some cool projects under Marco Bucci at the time, I believe he just started at Karolinska.
I worked for a couple of years in medical imaging (on a RIS) and our customers were very Radiologist focussed for everything except head scans (where the neurologists also read the scans).
I would hope to see AI-based assist technology hitting the market in the next 3-5 years for X-Ray/CT. Something in the form of the different rendering modes that you can use in a viewer. It's hard to tell though because the whole field is driven by hardware not software. Software seems to be an afterthought. The software seems more focussed on lock-in (integration, meh).
I had a vision for a future where the doctor in a hospital could push an image out to the "cloud" of teleworking radiologists, with the image being read in real time. It would be like load-balancing all of the work over the entire world. Technically it's tractable but the combination of privacy issues, the aforementioned hardware-driven market and the state of Hospital IT is what makes it impossible. Well that and the scaling problem (you need a critical mass of top-quality teleradiologists on your side to do it).
I'd say the couple of MRIs I've had done took around 10-15min or so. I think I shifted a few mm slightly at one point (possible since you're not quite bolted down, just held firmly). For 30 minutes I'm quite sure I'd probably shift around quite a lot, either involuntarily, because I got uncomfortable, or because of mild claustrophobia. :/
Non-radiologists already see all the relevant imaging, they’re just not nearly good enough to read them. More machines won’t change that.
Then we move on to elective surgery (planned). MRI with the best available resolution will increase diagnostic specificity and avoid unnecessary operations to labrum's, meniscus, etc. They don't need to be done in hospital and you can shop around.
At this point we're looking for problems to fit this solution, poor business model. Not surprisingly, limb only MRI machines haven't been successful.
Doctors had no clue what was going on.
Some of these meds are beyond scary.
Kids still wake up from nightmares of having family and teachers preparing them from what seemed a likely funeral.
See a different doctor and explain symptoms. “Oh yes, it some times does that.”
Getting correct diagnosis and meds is such a tricky topic.
I’m curious kind of institution you’re at? Everywhere I’ve been (NE) it’s fallen down academic lines: adverse impact of unneeded antiviral tx vs. mortality benefit in hsv encephalitis is incredibly one-sided, and time sensitive. Academic tertiary care institutions basically considered it borderline malpractice not to just initiate antivirals and d/c later. Non-academic secondary care institutions agreed in theory, but basically only started antivirals if everything else was off the table and/or imaging was characteristic (aka, either too damn late or later than it should be), but cases were rare enough it didn’t mean much in practice.
Saw 3 suspected cases recently, all started acyclovir within 1h in addition to the antibiotics, while awaiting lumbar puncture.
Cool device which could make MRI scans more accessible, and also paves the way for specialized scanners that only focus on a particular body part. I like medical tech that does a "good enough" job in exchange for being much cheaper than fully featured devices.
Consider patients who are unconscious (or awake but unreliable) due to head trauma, stroke, etc. You can't do a proper MR safety screening interview to find out if they have ferrous metal or other conductive objects in their head. The magnetic field can potentially torque an old aneurysm clip or piece of shrapnel, and the radio frequency excitation field can cause heating and burns if there are antenna-like conductors present.
MRI is slow and the images are easy to ruin if the subject moves around too much during the long acquisition time, so bouncing around in the back of an ambulance isn't the ideal setting. A 3D volume with whole head coverage and suitably fine spatial resolution can take several minutes to acquire, versus just a few seconds for X-ray CT. The MRI signal to noise ratio is also proportional to field strength, so low field systems like this are at a disadvantage for image quality. On the plus side, low field does mean less risk of moving ferrous material inside the subject.
Are we really not capable of detecting such dangers externally without patient input? It seems like detecting even small pieces of metal would be relatively trivial.
1) Speed.
2) Depiction of bone (less relevant if it's not a trauma case with suspected broken bones).
?) Risk to patient in case of internal metal.
Some MRI suites are set up with airport style metal detectors to prevent people from accidentally bringing metal into the magnet room. I haven't heard of metal detectors being used to screen non-responsive patients, though.
It's a reasonable question, but I think that even if some instantaneous metal detector with a false negative rate of 0 could be made, emergency docs would rather scan for five seconds to get a CT than five minutes to get an MRI that has coarser resolution, poor bone depiction, and a chance that the whole image is ruined if the patient moves.
What I'm saying is, why isn't there a sensitive enough metal detector which outputs a binary value of whether or not a dangerous level of metal is present? You need to check for two things I imagine: ferrous objects which could be pulled by the magnet, and conductive objects which would heat up when absorbing the MRI RF pulses. Both seem possible to do with a bedside device.
> According to the guideline, diffusion MRI should be considered more useful than a CT scan for diagnosing acute ischemic stroke within 12 hours of a person’s first stroke symptom. In one large study, among others, that was reviewed for the guideline, stroke was accurately detected 83 percent of the time by MRI versus 26 percent of the time by CT.
Main thing they need to know is stroke vs aneurism and accuracy is really important.
This technology will mostly end up in imaging centers, improving throughput.
Still, an ER MRI is wildly unlikely. “Possible evolving emergency” and “an hour in a tube where we can’t see you” don’t play well together. Any chance you’re confusing CT scan for MRI? Cause -that- we would do for a head trauma like 1000% of the time.
I think the combination of weird blood work + medical mystery + stabilized meant I got an MRI. wish they'd gotten to the bottom of it..
If you solve or alleviate those issues it becomes more attractive. There is a fair bit of research around potential trial benefits if the contrast provided for some emergency procedures already.
Ugh, I just wrote this long-ass post and lost it. Whatever, here's the short version:
Stroke is a clinical diagnosis, not a radiologic one.
CT will catch hemorrhages or large infarcts just fine. That's the important stuff: big infarcts cause big tissue damage. Tiny infarcts cause tiny tissue damage. MRI's superiority over CT is in that it catches smaller infarcts, and catches infarcts early. If I see a patient that screams "stroke" and the noncontrast CT is negative for hemorrhage, it's ischemic until proven otherwise. I don't need an MRI at the less than six hour stage and, while having one would be nice for malpractice reasons, whatever, I don't actually need one for your care. I may follow-up with an MRI if it's less certain that it's a stroke: tumors, infection, etc. that look like strokes. But, key - those aren't pressing, time-wise, the way a stroke is, if they look like a stroke ("look like" implies things about the nature of the underlying condition.)
After 6 hours we've passed the TPA stage and we're looking at clot removals. Here we need to know the exact territory of the infarct. If I'm bothering with imaging, yes, MRI/MRA, but that's not about finding the kind of stroke - it's about telling the interventionalist where to go.
The method that works where I didn't accidentally close the last tab associated with a particular renderer process (or, TL;DR, didn't close any tabs), is to promptly figure out which renderer process is behind the tab in question via chrome's task manager, quickly attach to it with gdb, then `generate-core-file (filename)`, and grep through the result for my text. (Usually `grep -aC100`.)
Alternatively, hibernating generally seems to always(?) save the disregarded bytes to disk (the associated memory regions immediately get used for something else, so they stay in in the pagemap); then I can reboot the machine, carefully prevent it from resuming, boot to Linux, mount the FS readonly as appropriate (since it was never unmounted cleanly), then go through the hibernation/swap image. (Bonus points for then resuming once you're done.) I recovered a family member's lost draft email this way once (TIL Gmail encodes emails in both HTML _and_ HTML-inside-JSON O.o).)
I'm speculating, but probably not. The images would be blurry and unusable if taken in a busy ambulance on road to the hospital. Could do more harm than good.
Having this in a stable home would be awesome on the other hand, but there is too much vibration and everybody trying to grasp handlebars and keep equilibrium when you are in an ambulance on duty.
I could be wrong. I do not master this technology, but if you need absolutely remain motionless in the big machines, I assume than smaller ones would have the same requisite. Ambulances are not stable by default. Everything bounce.
I’m not saying it couldn’t work with a bunch of extra RF engineering, but it’s not a given. For that matter some locations mist don’t have very good mr imaging regardless of setup.
quick search shows in 2016 USA has 37 mri/1mm people, mexico has 2 mri/1mm people
I've been to the RSNA, am involved in healthcare software in the USA, and seeing what companies like Phillips, GE, et al, spend on floor space at this conference, it seems difficult to imagine these companies yielding their market position for cheaper machines to reduce costs. MRI equipment is huge business (these companies don't bat an eye spending $1,000,000+ for a conference such as the RSNA because this is where they wine and dine and make every hospital exec feel "special" so when it comes time to buy x MRIs, the sale alone will pay back the conference cost 10 fold. These conferences are expensive. The sales pipe is long (and thus expensive).
There may be companies creating and selling these, but the heavyweights don't like losing a market opportunity in "their" hospitals. I'd be very reticent to think there will ever be lower costs in the ER for offering said device/service.
Please don't get me wrong, I'm excited for limited use machines that can provide the basic information needed at a fraction of the price. I'm very leery of US healthcare institutions making a rational, patient-friendly cost conscious decision.
That was going to be my question. From my current understanding you can't go into the same room as an MRI scanner with any metal in your pockets. The portable nature of this device made me question the safety aspect.
I believe GE came out with MRI machines a while back that were specific for limbs. This really does not seem much different other than it is on wheels and you can possibly position over a torso in a bed if it isn’t metal.
That said, many universities do let people use the human scanners for other research. It’s kind of a pain to do with animals, because you’re paying $500 an hour while you scrub the room down afterward and wait for the air to cycle, but it’s the only way to scan larger animals (primates, pigs, dogs, etc).
Same MRI at a stand alone clinic is about $2k.
It’s ridiculous.
Sure, they don't have fast 3T machines, but still are useful for DIY cancer screening for the paranoid like me (for those that aren't familiar with imaging tech, MRIs don't use radiation).
It is solely US thing that medical procedures have astronomical cost.
Which makes sense if the machine cost is around 1,000,000, appointments were every half an hour, so, let's say they make 15 scans per day at 300 each, it makes 4500 Euro/day by 220 days/year that is around one million Euro/year.
You take out of it - say:
250,000 Euro for the machine (for 5 years)
250,000 Euro for personnel
250,000 Euro for maintenance, power, other costs
50,000 Euro for something else I don't know
And you are still ahead for 200,000 Euro/year, i.e. roughly 20% of your investment.
The key patent makes for interesting reading [1]. They use neodymium permanent magnetic rings. I wonder if building a crude version of Hyperfine’s machine is within the realms of a DIY project.
[1] http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=H...
- https://www.opensourceimaging.org/project/instructional-tabl... - https://tabletop.martinos.org/index.php/Main_Page
Whether or not such techniques are good for accurately detecting lesions seems to still be a bit of an open question. (It's less relevant to my particular research interests for now, but obviously extremely important for clinical use.)
A lot of the fallout from over-imaging (especially when, like MRI, there is no ionizing radiation so the test itself isn't harmful) is due to physician behavior and standards of care. But those behaviors and standards can change over time.
A bit tangential, but I suspect that at some point, we will think it anachronistic that cardiologists tried to visualize the heart's function by listening to its sounds with their ears.
You must be an accredited US health care provider.
System usage is approved for patients 2 years and older.
Your institution must be able to supply a wired ethernet connection to the device once every 14 days."The magnetic field is way less strong (0.064 Tesla compared to at least 1 in most machines), but the machine doesn't have to generate heat while producing a magnetic field
So long as they stay under their critical temperature. If that changes… well, a lot of liquid helium is about to stop being liquid.
And that's one of the reasons why a permanent-magnet MRI is so interesting -- it doesn't depend on a constant supply of power (for the helium cooler) and gaseous helium (to replace lost gas), so the system is portable, and maintenance costs are likely to be much lower.
But you can get high temperature REBCO tape now and get super conductors that can be cooled with liquid nitrogen.
Low field magnets are usually just solenoid coils. There are a number of low-field magnetic resonance devices, including benchtop relaxometers, which use either permanent magnets or electromagnets. This one just uses an electromagnet, I believe, and it looks like it's in a Helmholtz configuration. This is a smaller version of a design used primarily in veterinary contexts, e.g. so you can walk an upright horse into it.
(Edit: Someone below says it's permanent magnets here. Can probably look up their patent or FDA application to be sure.)
If it warms up, it’s no longer superconducting and all that current starts generating heat which boils the liquid nitrogen off, which can be quite spectacular. Plenty of videos on YouTube.
So yes, turning the magnet on and off is not trivial at all, but as long as you keep it cold, you’re good.
This new device seems like it will break down so many barriers, both in terms of cost and practicality, in Haiti and other developing countries.
I hope it makes its way there!
https://www.fiercebiotech.com/medtech/fda-clears-world-s-fir...
Small permanent magnet NMR spectroscopy units first showed up in chemistry about 10 years ago:
I forget what it’s called now but you can build a permanent magnet of upward if .5 or 1T by packing a bunch of keystone-shaped rare earth magnets with differing field alignments into a high tensile strength retaining ring. This causes the fields to be additive, but God help you if you manage to break the damn thing. I watched a video on how to safely put two large rare earth magnets together without shattering them, and YouTube recommended an infomercial by some company at the high end of Tesla ratings for permanent magnets. It was kinda nuts.
Some hospitals in Germany actually have vehicles containing MRI units which they dispatch when a stroke is suspected.
In the US there are 37 MRI machines per million population, even in other relatively rich countries like France this is much lower at 14 per million population [0]. Is it just the cost of the machines, or are there drawbacks that limit their use as general purpose diagnostics tools?
[0] https://www.statista.com/statistics/282401/density-of-magnet...
I see lots of immediate uses for this. Pro-sports will obviously want it, the military will too, field hospitals in e.g. Africa. Lots of possibilities here.
Can anyone tell me where this device will be manufactured?
This would be especially useful in the developing world.
It is quite cheap here in India already (got an orbital MRI last week for $105.10, including radiologist's fees; it can go as low as $40) but having it cheaper and more easily available would help a lot more people.
Basically anything in US will be 10X expensive because we have wonderful and very efficient healthcare for doing even the most basic things like CT, XRay, MRI etc. /s
Will this thing have enough to be useful?
It’s not quite as simple as field strength equals resolution, but generally it is easier to achieve high resolution with higher main field strength. See for example mouse scanners at 12T