Preliminary Thoughts On The Midjourney Scanner

Midjourney is an AI image model. If you’ve ever used Nano Banana or asked GPT to draw you a picture, it’s like that, except from a medium-sized startup instead of a tech giant. Earlier today, they announced a pivot to medical scanners. The new MidJourney Scanner , which they describe as “a bold new kind of machine to reimagine the foundations of healthcare and our relationships to our bodies”, will be a tank of water surrounded by a ring of ultrasound scanners. The patient goes into the tank, the scanners emit ultrasound from all angles, and then some fancy AI reconstructs the echoes into a 3D picture of the body. The result is ultrasound tomography: the same sort of rich data as a CT or MRI, but done via ultrasound, with no harmful radiation, in twenty seconds. This is cool, and it’s great to be ambitious, but I think the narrative among the SF AI crowd has escaped its basis in the medical facts, so I want to throw a bit of cold water on it. I’m a psychiatrist, which is about as far as you can get from radiology while still being a doctor, so this is speculation only, and you can ignore it if you find an actual radiologist or ultrasonographer with opinions. Still, my take is that this scanner isn’t useful for most current serious medical applications. It could potentially be used to pioneer a new class of low-risk screening applications, but it’s unclear whether these are good, and depends a lot on what other future technology gets invented in parallel. Why can’t this immediately replace existing medical image modalities like normal ultrasound, CT, or MRI? Ultrasound is great, but it can’t penetrate bone or air. Many things doctors want to look at involve bone or air in some way. For example, the brain is behind the skull, which is a bone. The bowels are full of air. The lungs are super full of air. This limits ultrasound to the remainder - especially parts of the digestive, endocrine, and vascular systems, and superficial tissue like fat and muscle. (it’s actually worse than this. Normal ultrasound can be used to image certain organs like the heart or prostate, but only through the technician carefully angling the probe. Midjourney hasn’t given details, but most likely their Scanner won’t be able to match this level of precision, so the heart, prostate, and some other usually-ultrasound-compatible organs will be outside its reach.) Most MRIs or CTs involve one of the organs ultrasound can’t reach (this would be one reason doctors might do an MRI or CT, instead of just using ultrasound). In other cases, you don’t know what organ we’re looking for, and you want to be able to see everything (for example, if you’re scanning for cancer metastases, you can’t leave the brain and bowels out of the scan!) So this technology can’t replace most MRI or CT. What about replacing ordinary ultrasound? One of the big advantages of ordinary ultrasound is that it’s a cheap machine you can keep on a cart and connect to a patient who’s lying in a hospital bed. Even though it might work better to put the patient in a giant water-filled tank surrounded by hundreds of ultrasound machines, if you tell your hospital orderlies “please transport this frail 90-year old to my giant water-filled tank, and lower them in slowly” they will stab you with your own scalpel. So this would need to be much better than ordinary ultrasound to capture even a fraction of these use cases. But ordinary ultrasound is already pretty good, this technology is untested, and it will be hard for it to be that much better. Aren’t there a few edge cases that are poorly-served by existing modalities and ordinary ultrasound? Yes - the classic one is certain types of breast cancer, which don’t show up well on mammography against dense breast tissue, and require too much of a search for ordinary ultrasound. It’s a perfect match for this technology, which is why ordinary medical device companies have already created an ultrasound tomography scanner for the breast and it’s used regularly in medical practice. It’s not quite as neat as the MidJourney Scanner - the patient just lies on a weird-shaped table in a position that puts their breasts in a pool of water, instead of submerging the whole body, and you get correspondingly less coverage - but it works fine for the rare case where this technology actually fills a gap. There are probably other edge cases I don’t know about, but they weren’t important enough for normal medical device companies - who absolutely know about this technology and have thought about it a long time - to invent devices for it. Couldn’t this technology enable new, non-specific-diagnostic uses for healthy people? This is where Midjourney seems to be going. Aware that this doesn’t fill a specific diagnostic hole (and would probably be annoying to get past the FDA), they’re imagining something where healthy people go for one of these scans regular