There's a risk of echos of Theranos here. A paper apparently describing this ultrasound approach has been uploaded to arXiv [0]. If so, the resolution demonstrated is nowhere near sufficient to detect small changes to anatomy, let alone monitor them over time. Future developments could obviously improve on that.
[0] “Whole Cross-Sectional Human Ultrasound Tomography” https://arxiv.org/pdf/2307.00110