The website is calling for their full-body MRI-replacing ultrasonic scanners to be so cheap they're part of a spa session.

TBH, this is already a red flag for me, like so many other "tech bro invents X" stories, though I am also aware of stories were "company realises Y is overpriced in medical purchases, makes Y cheaper, finds all hospitals think it is a scam and refuse to buy unless they raise prices".

Conventional ultrasound scanners are already cheap. Why can't a big ultrasound scanner be cheap too?

What makes MRI machines expensive is that they are big helium-cooled superconducting magnets that have to be continuously kept at a few Kelvin.