Given that current ultrasound probe technology (including butterfly) relies on the probe being essentially in contact with the tissue being imaged, itβs hard to imagine how this set up can be effective with the imaged volume so far from the transducers, since there will be a huge amount of dissipation in the water bath, but maybe they have found a way to solve that? Also, I imagine that the quality of the images, such as they are, will fall off very quickly in larger patients. Will be interesting to see.
Exactly my concern too. There are techniques like synthetic aperture focusing which can correct some of these errors to some degree but they're complex and have harsh limits of their own. It's always better to not have the errors introduced by the distance and water volume in the first place. The thing which makes no sense about this entire approach is we already can not have those errors.
I've been looking up relevant data and reading some papers to determine if I'm missing something there but, so far, the approach looks pretty much 'all downside' with the few upsides being: 1. Faster to image full body, 2. Don't have to have some technician poking you with an ultrasound wand, 3. Looks cool?
But I'm just an imaging and DSP guy, you're the actual radiologist. If you don't mind there's one question I'm not sure about. Trying to 'strong-man' the product concept, the only potential benefit of the approach I haven't crossed out is if there's any meaningful value from having additional simultaneous receivers off-axis from the emitter? I mean value which can't be gained from just moving a single emitter to another axis, grabbing more images and then cross-registering those. Even then, the off-axis receivers are always co-planar with the emitter, which seems like it would greatly limit any utility.
The downside column I've got so far is vast... and it's not just distance, there's also the turbulance in the water, micro-bubbles from the ongoing submersion of body and platform into the tank, the thermal disruption at the boundary layer, the fact the human is freestanding with no support while being submerged means they'll be far less stationary than a human comfortably reclined on a ultrasound table, it goes on and on.
Right, this is where I'm at, in trying to 'strong-man' it. CT is great as a source and a detector, but when you add multiple detectors and can use scattering to your advantage, we're able to lower rad dosage for comparable images. So, yeah, what if each receiver is able to handle the ultrasound scattering better than we thought.
That's the only way this thing adds up in my head.
> what if each receiver is able to handle the ultrasound scattering better
Yes, that's the most charitable 'Steel-man' possibility I've still got open. Still a lot of unknowns but I suspect they're just unknown to me and probably already known to those in the field. It's not like this off-axis receivers concept is remotely new in computational imaging. So I went looking for priors and proxies that use the same idea - and found a bunch. There are dual-wand, dual-leaf and quad-leaf 'flex-jaw' arrays that basically just add extra receivers on tilting 'wings' to conform to cylindrical and non-uniform shapes. They don't seem to be used much for medical imaging but are common in things like metallurgical inspection, materials analysis, etc.
I'm still unclear why they aren't used much in medical but I suspect it has to do with the fact that medical ultrasound is highly constrained. It can work well in fat and soft-tissues but bone absorbs and reflects ultrasound fiercely and different tissue densities respond differently. This makes off-axis receivers likely to be occluded, reducing how often it contributes to improving imaging.
My biggest question about the MJ product hypothesis isn't whether it can work, it's whether it will work meaningfully better than easier, cheaper surface-contact methods using the same transducer chips. If it's true that additional off-axis receivers do provide increased value for medical imaging, then it should be even better to do that with a flexible semi-arc of chips that can directly touch the skin. I just don't see how any off-axis benefit can overcome the drastic signal degradation introduced by moving the chips 200-400 times farther way and trying to correct for the turbulent hurricane of that huge liquid volume.
