[doctoring]

Very interesting overview of the technological / materials breakthroughs to enable miniaturization.

From a physician (specifically radiologist) perspective, I'm a big fan of handheld/point-of-care ultrasound and am excited about their potential at democratizing a very useful and low-cost/low-risk imaging technology. (I also own a Butterfly.)

That being said, the "cart-based" ultrasounds will likely always have a place in a hospital; the size of the ultrasound probes is not why the cart is big/expensive/useful. The cart is a big floating screen and also an image/record management system. You (or at least, a trained ultrasound technician) can manipulate ultrasound parameters and annotate images (critical for ultrasound interpretation) way way faster on the cart's set of wonky keys/dials/trackball than on a smartphone.

Also, with the rise of handheld/point-of-care ultrasound, we've noted with amusement in the radiology department the frequency with which patients get referred for additional imaging because the ED or primary doctor saw some pathology on their handheld ultrasound... and when we take a look it is just not there. I think this is probably more of a training issue, as ultrasound is truly quite challenging both to perform AND to interpret (and a major part of using an ultrasound probe is essentially real-time interpretation), which is even more challenging given the lower image quality and field-of-view of smaller probes.