Yes, I was thinking about FUS as well! There are clearly ways to penetrate bone, but I have not seen it used for imaging, only for ablation. But I am not an exp

Yes, I was thinking about FUS as well! There are clearly ways to penetrate bone, but I have not seen it used for imaging, only for ablation. But I am not an expert there and it sounds like you have more knowledge in that area than I do. Pedantry appreciated.