Discourse software may work for you in your area of concern and customers. [A] Integrating on the fly annotations to image store for large important data set isn't a new problem that hasn't already been solved. Networking and storage is cheap. Look for expert cloud infrastructure provider specialising in the medical field? Expect a little bit of premium on pricing above services from namecheap.com? [B]
A. https://en.wikipedia.org/wiki/Discourse_(software) B. https://namecheap.com