[haldujai]

> The brain is encased in bone, so you might get some penetration but it will be very limited.

Radiologist as well. Remember this is full wave inversion not pulsed wave B mode. You can get much more useful information from both high low frequency and capture transmitted waves.

There is promise with this and we use it for example with MRgFUS. With advanced computational models or patient specific CT/ZTE MR aberration correction it is theoretically very feasible to image the brain with ultrasound, whether that’s more useful than say portable low field strength MR is a different question altogether.

> This is cool, but ultrasound is not CT.

Not to be pedantic but since this is a tech forum I would clarify that FWI US is computed tomography by definition (at least in this and many applications). Gas degrades conventional CT too, it’s just worse with US as you have little to no forward propagation and of course innumerable interfaces in the lungs to reflect and scatter.

[jmhmd]

Yes, I was thinking about FUS as well! There are clearly ways to penetrate bone, but I have not seen it used for imaging, only for ablation. But I am not an expert there and it sounds like you have more knowledge in that area than I do.

Pedantry appreciated.

[TheOtherHobbes]

What's the use of FWI for a moving target - which someone floating in a spa most definitely will be?

This is a fever dream, not a practical diagnostic technology.

I can imagine it being useful if you happened to own an imaging product and wanted to train a model on human body shapes and sizes.

But dunking people in a golden spa - why golden? why not pink or teal? - and waving a ring of US over them, at distances which make high resolution impractical, to tell them their medical fortunes is... eccentric.

I'm being scathing because there's no solid science behind this, and if there had been solid science MJ would have published it in a paper.

This is pure marketing. And if you're going to do that, you should at least include some dolphin petting.

[code51]

What does "more useful" mean in this context? Can you solve gas-filled bowels with the mode difference?

[lebovic]

Full wave inversion uses all of the information from the wave and more intense computational tomography to image structures that pulse wave B mode cannot, though gases are still a problem. Computationally, if you squint, it's similar to the work Midjourney does with AI image generation, as it progressively generates a structure that fits the data.

Ultrasonic waves can penetrate most structures in humans, including the brain. For example, with focused ultrasound (as they mentioned with MRgFUS) you can burn specific structures in the middle of the brain without any incision.

To use this for imaging, you need lots of transducers (MRgFUS typically uses 1024 for ablation, and Midjourney is proposing 358,000 for imaging) and massive advances in computational tomography capabilities. There will still likely be pockets of low confidence where there's a lot of air, like in the lungs. But with sufficient information on what's happening around those areas, you'd still have something that's medically useful.

[treees]

Ultrasound researcher here: this work is almost certainly not full wave inversion. You're right that FWI can be done in this kind of setup. Notably, a lot of people are trying to use circular arrays of ultrasound sensors to do FWI, particularly in the brain or the breast. But, it's a challenging inverse problem to solve and as far as I know, it's still extremely slow - nowhere near realtime.

The data they show is almost certainly a normal beamforming algorithm like delay and sum, possibly with some simple speed of sound correction. The most similar paper I know of is here in Nature Biomedical Engineering from a team at Caltech. https://www.nature.com/articles/s41551-026-01660-4