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  • Hacker News
  • Interesting technology, and of course transcranial ultrasound has been around for a while. But ultrasound even at low doses, does stimulate neurons in the brain, and so until we have more data I would be careful about applying it to the entire brain or portions thereof. transcranial focused ultrasound, which has been studied and shows great potential in medical or therapeutic domains, is highly precise, and even then we see that it can have adverse neuropsychological effects depending on the area stimulated, frequency, used, duration, and natural variance between individuals.
    by insane_dreamer
  • This is ridiculously cool, but I have a ton of questions.

    > The bubbles themselves are pockets of sulfur hexafluoride encapsulated in lipid shells. They're an FDA-approved contrast agent,

    Combined with ultrasound, could these be causing damage of any kind to the vasculature?

    > A few years ago, a paper came out that blew our minds. The idea was that you can decode what someone is looking at just from their brain activity.

    How realistically close can this get to reading thoughts, visuals, etc.?

    Do we have a path to imaging people's visual cortex? Their inner lives, dialogues, memories? (Scary thought - this could be used as an interrogation tool without consent. "Did you kill Bob?" could be a simple brain scan.)

    Can it be done in real time in a feedback loop and perhaps be used as an advanced reinforcement learning system?

    by echelon
  • This kind of mind reading could easily become the end of human privacy.

    That's bad enough in democracies, but the consequences in more common forms of government seem really dystopian.

    by BurningFrog
  • Who could've thought that injecting SF6 into blood vessels is actually safe enough to be FDA-approved... interesting.
    by wildylion
  • Contrast-enhanced ultrasound (CEUS) with microbubbles has been around clinically for 20+ years. There are many contrast-agent manufacturers, e.g. Bracco (SonoVue/Lumason) or GE Healthcare (Optison). Safety-wise it's probably better than CT iodinated contrast or gadolinium MRI agents, and it's pretty well-established at this point.
    by Preseason8448
  • Per Wikipedia, it "is a colorless, odorless, non-flammable, and non-toxic gas."

    When used as a contrast agent for ultrasound, it "has been used to examine the vascularity of tumours" -- which would be similar to its use in the OP. Then "[i]t remains visible in the blood for 3 to 8 minutes, and is exhaled by the lungs."

    So -- not collected and excreted by the liver, as I at first thought.

    by fernly
  • It feels like ultrasound is solving everything for the last week.
    by w4yai
  • I think the more interesting angle is focused ultrasound which is proposed as a solution to a whole lot of diseases
    by breppp
  • There were a lot of people who declared very loudly last week during the Midjourney discourse that this was an impossible use of ultrasound.
    by qgin
  • Correlated events :)

    The team behind this post is (or at least was as of a few months ago) working with Midjourney.

    by throwaway_7274
  • Not trying to sound alarmist at all but I am wondering if ultrasounds are safe to be used like this? My understanding is it's basically a high-frequency sound wave which is probably fine for most tissue usage, however here it says it's scattering off of red blood cells. I don't know why that feels so unsettling to me.
    by trevor-e
  • Waves scatter off of everything so that's not of concern. Depending on the intensity, frequency, and tissue in question ultrasound can have an effect. Someone elsewhere linked to a couple academic papers on the topic.

    I share your hesitation about using this on the brain, at least barring exhaustive long term animal model trials. Subject a mammal to this every day for 10 years and show that there are no negative effects relative to the control.

    by fc417fc802
  • Every few years one of these ultrasound companies comes around and promising to revolutionize medical imaging and nothing ever comes of it. Anyone remember https://www.openwater.health? The same ideas are in a perpetual state of being reinvented and part of me thinks its just a hustle for the MIT Media Lab/Stanford Imaging grads to give them something to do.

    The tell is "super resolution", "brain computer interface" and "mixed modality" -- adding some contrast agent here, or maybe an IR light source.

    It turns out the nyquist limit, diffraction and physics are real things.

    by iamleppert
  • but technology is getting better all the time what doesn't work because they only have one Tesla, well shit, let's try it with 100.
    by fragmede
  • It doesn't work until it does.

    The same thing has been said about robotics, AI, space travel, etc. etc.

    I'm not saying this is the way, and I have significant questions of understanding thought based on reading brain activity, but I wouldn't put down the entire ultrasound field.

    by pedalpete
  • Meta is also going at it [0], which inevitably makes me ponder some orwellian questions for the near future:

    If I bring my pet mouse to the cinema and my friend scans the movie back using his apple ifmri does the DRM still holds or will the mouses be DRM locked? Will my iris suffice for booting my computer or would I need to press accept all brainwave cookies? Can I email my local Flock representative to install a new Brain Pole in my neighborhood? I saw a bunch of dark thoughted young males around and my amazon think camera says the probability of missing packages increased.

    [0]https://ai.meta.com/blog/tribe-v2-brain-predictive-foundatio...

    by frangonf
  • The current state of the world, where we have insane and ubiquitous surveillance tech but our packages are nevertheless being constantly stolen (with the thieves "caught" under said surveillance but with no one bothering to enforce it), is certainly an interesting one.

    I wonder what Orwell would have thought.

    by paytonjjones
  • Certainly the thing of sci-fi nightmares, but not practical.

    All of these imaging techniques are very involved. Ultrasound requires direct contact and this technique only works with a long IV infusion of bubbles. fMRI isn’t going to be a portable device that you can point at something for many reasons.

    The connection to what you’re thinking is more sci-fi than reality. This technique could theoretically see some changes in blood flow to different regions, but what would that mean? Is the patient having anxiety, or are they just nervous about the IV injecting bubbles into them to travel to their brain and the machine attached to their head?

    by Aurornis
  • The imaging stuff is cool but the homepage is making me wince.

    There's a compelling argument to be made that the level of detail in "mind reading" they are gesturing at is plain unrecoverable with hemodynamics. There's an irreversible loss of dimensions that occurs the instant you start recording blood instead of spikes on the neural circuits themselves, and it's not at all clear that what a VC reading the words "telepathy" is imagining even survives that transformation.

    What you have is food delivery data for a neighborhood, this can tell you a surprising amount, including when they might throw a party. What it can't tell you, however, is who wore the best outfit and what was talked about over dinner. The information simply does not survive across the interface.

    There is a spectacular canyon between "informed interpretation" and "mind reading"

    by Unearned5161
  • re: imaging red blood cells

    The super-resolution trick as they’ve done it is highly reliant on the sparseness of the bubbles. If you imagine a point or a very sparse set of points at low resolution, you can fit for the locations of those points even though you don’t see them clearly. This is a common technique in radio astronomy and (I assume although I don’t have personal knowledge) astrometry, and compressed sensing was an extremely hot field a while back.

    But RBCs are weird squishy things, and they fill the bloodstream quite densely, and ChatGPT estimates that they’re spaced about 20µm apart and that, when confined to a capillary, they’re about 7µm long. (And that sounds at least plausibly correct to me.)

    So, even ignoring the much worse scattering properties of RBCs, they not nearly as sparse. You mostly lose a whole dimension of sparseness and up trying to resolve the entire capillary. Which seems possible but much harder. Unfortunately, brain capillaries are about 40µm apart, so the result might be a mess.

    The article did not say what wavelength they’re using or what their native (wavelength/2) resolution is.

    by amluto
  • I believe this is also used for regular astronomy with dithering
    by malfist
  • I’m a complete layman to this field, but what the article did say was they’re hopeful that AI/ML can help develop a model that can pull out information such as the scattering caused by RBCs (which is present in the large volume of data gathered by the probe but is too weak to be used for manual techniques) and turn that into meaningful visuals. That’s gonna require a ton of data and that is exactly what they are trying to gather now with what they have built so far.
    by sheepscreek
  • Showing us a technique that is entirely reliant on sparseness and then saying they hope to employ it on something that isn’t sparse at all (blood cells) does feel misleading.

    I’m filing this in the category of technologies I wish could be true, but for which no plausible path to overcoming the obvious limitations has been provided.

    by Aurornis
  • > The bubbles themselves are pockets of sulfur hexafluoride encapsulated in lipid shells.

    The high resolution images were generated by injecting sparse bubbles of this contrast agent. How sparse are they? Is the image we see a stacked set of many bubbles over time composited together?

    Their aspirations at the end of doing this without the bubbles are great, but there’s a big “now draw the rest of the owl” energy around that leap. The first technique relies entirely on the bubbles, but they provide no explanation for how they think this could be achievable without the bubbles other than vaguely saying that technology is advancing.

    by Aurornis
  • Cool work and proof of concept, and very excited to see where this goes. However, I do think there is enough exaggeration and missing information here that it warrants some critical appraisal. What's really missing is a comparison and validation with any existing medical imaging tech. Whole brain, contrast-free neurovascular imaging is essentially solved with MRI, why not run a scan and compare? Ultrasound is of course portable and less expensive, but MRIs are actually widely available in most cities at reasonable cost for medical workflows, and low-field brain MRI is addressing the portability and cost issues to some extent. I guess they are pitching this as a wearable "telepathy" device, which I think appropriately differentiates their product, but of course, this wording also invokes a framing that "you won't / don't need to know how it works," which invites skepticism and a higher bar for validation in my view.
    by thaw13579
  • most cities where?
    by kyawzazaw
  • > MRIs are actually widely available in most cities at reasonable cost

    Typical wait time for an MRI in Canada is 2 months.

    by virissimo
  • As the article says, their ultrasound machine costs about as much as a smartphone. It’s about $4000.

    An MRI machine costs roughly 1000x as much.

    by janalsncm
  • "MRIs are actually widely available in most cities at reasonable cost" - I live in one of those first-world countries, and our citizens regularly wait many months if not over a year to get a single MRI scan. Yes, it's not just an issue of the MRI but the entire medical system, but the point still stands. Were there machines that were one or more orders of magnitude cheaper and simpler to run - I think we would see a marked increase in availability.

    I agree on your ground-truth desire, and I would hope they've done a lot of that to validate what we see here.

    by switchbak
  • Even low-dose ultrasound (what they use on pregnant woman) results in ultrastructural changes in brains [0], specifically at the nodes of Ranvier (the gaps between myelin along axons). See also [1] for a review.

    [0] Ellisman MH, Palmer DE, André MP (1987), "Diagnostic levels of ultrasound may disrupt myelination," Experimental Neurology 98:78–92 https://pubmed.ncbi.nlm.nih.gov/3308504/

    [1] Quarato, C.M.I., Lacedonia, D., Salvemini, M., Tuccari, G., Mastrodonato, G., Villani, R., Fiore, L.A., Scioscia, G., Mirijello, A., Saponara, A. and Sperandeo, M., 2023. A review on biological effects of ultrasounds: key messages for clinicians. Diagnostics, 13(5), p.855. https://pmc.ncbi.nlm.nih.gov/articles/PMC10001275/

    by davi