First Images of a Heart Injected with Liquid Metal | Hacker News Reader

First Images of a Heart Injected with Liquid Metal

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82 pointsmwc17 comments

I've worked a lot with liquid gallium (in semiconductors, not medicine) and it is pretty nasty stuff. It might not be very reactive, but it is extremely corrosive to other metals and can crystallize very quickly if given a seed.

A quick search for a gallium MSDS confirms that it isn't exactly regarded as medically safe right now: https://www.rotometals.com/v/vspfiles/downloadables/MSDS_GAL...

It appears to mimic iron(III) in biology which would be all kinds of concern about what it's doing to red blood cells.

People used to play around with Mercury and even ingest it since it's not supposed to be reactive. Turns out it's stupidly toxic but nobody figured that out until recently.

> People used to play around with Mercury and even ingest it since it's not supposed to be reactive. Turns out it's stupidly toxic but nobody figured that out until recently.

Well that's only partially true. The toxicity of mercury was speculated as early as the late 1600s [0]. Then in the 1920s Alfred Stock was doing "modern" research on its effects [1]. So sure, people played around with it, but it's toxicity was figured out a long time ago.

Hopefully we've also advanced as a society since then in that we wouldn't handle something so carelessly - however it would be a little naive to actually believe that, I'm sure 100 years from now our descendants will look back and judge us just as we do.

> Qian and co are optimistic. They point out that gallium is chemically inert and believed to be non-toxic in humans. And they say a small amount of the metal can be injected into the target vessels and sucked out afterwards without leaving a residue.

[0]: https://en.wikipedia.org/wiki/Johann_Jakob_Wepfer

[1]: https://en.wikipedia.org/wiki/Alfred_Stock

Bioengineering researcher here, who works mostly on analysis of vascular imaging.

Imaging in general is a field in medicine of increasingly growing importance - and as the article suggests its increasingly limited by resolution of the images. I personally see patient-specific diagnostics from image processing to be one of the most promising medical advances to expect in the coming decades. Image resolution is a major thing holding this back, it probably needs to improve ~2-5X for many applications.

This kind of thing is exciting, but probably at least a decade from clinical use, if at all from this particular technique. Use in research is itself quite interesting in at, at least to my knowledge, microvessels can only be observed by micro-dissection, which disturbs the tissue.

Being able to better observe microvessels clinically could have pretty big implications for heart attacks, strokes, cancers, and kidney functions.

The experiment (from the paper) was done on a in vitro (removed) pig heart (and kidneys, reported in the paper but not Medium article). In vitro studies often give much better images than in vivo because there is less

I am sceptical of the ability to retrieve the injected gallium, although I am not terribly familiar with its properties. I believe it is a quite rare and expensive metal, and the volumes needed for this would be small but not insignificant (maybe 20mL/ organ imaged?). I could see retrieving it being an issue, and particularly in the heart or brain, blood flow would need to be restored within a few minutes.

Iodine contrast agent, which this technique is compared against, is pretty nasty stuff. It gets filtered out by the kidneys, and is toxic to them. If anything, there is a movement to get away from contrast-based CT imaging of vessels and towards MRI or ultrasound, where contrast isn't required.

Radiographer here. MRI uses contrast about as much as CT and gadolinium toxicity turns out to be at least as bad (which took a while to work out due to the slow onset of symptoms). While our non contrast techniques are good and are getting better fast, nothing beats a good contrast run. However MR of coronary arteries isn't anywhere near as good as CT or cath lab imaging which is high quality. It is notable how poor the quality of that pig heart image with iodine based contrast is. It is laughable. A quick google of CT or cathlab angiography images will show examples vastly superior that were obtained on beating hearts in live patients - rather more difficult than direct injection into a dead, removed heart.

So nice to read this the day after I had a chest CT done using the iodine contrast agent. Interesting sensation when they start pumping it in, though.

On a related note, look at what gallium does to aluminium: http://youtu.be/9DEjE8jiwT8?t=1m7s

To be fair, lots of things will do that, since aluminum is an incredibly reactive element. Once you scratch away/through the oxide layer that normally protects it, you can get all sorts of stuff to react with it.

Somewhat higher resolution image on page 8 of http://arxiv.org/pdf/1311.6717v1.pdf

Speaking of filling organs with metal, I've read that the lungs have an absolutely amazing amount of surface area. So I got to wondering if we could somehow use a lung (say removed from a pig) as a super capacitor?

Maybe use a non conductive material to thinly coat the inside of the lung and then fill it with metal?

Or do that, then burn away the flesh and use it as a heat exchanger.

I'd be very reluctant to have gallium injected in me, but it's still a valuable technique to map out (and make casts of) hearts and vascular systems in animals or people that donate their body to science.

Neat, but unless this is in vivo, this isn't all that thrilling, as we've been doing this sort of thing with wax and plastic for more than a century. http://cruciblezine.files.wordpress.com/2010/06/circulatory-...

Some guy does it with aluminium and ants' nests: https://www.youtube.com/watch?v=IGJ2jMZ-gaI

And they say a small amount of the metal can be injected into the target vessels and sucked out afterwards without leaving a residue."

The most curious part of the story isn't there, how do you suck out the metal afterwards? What percentage are you able to reliably suck out?

»Without residue« sounds like 100 % to me.

Needing some education here. They took a pig's heart, dead, injected it with metal, and are impressed that this showed up in an x-ray? Gunther von Hagen with metal?

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