You’re loosely alluding to personalized medicine but envisioning is a very futuristic state we are very slowly moving towards. What you suggest is great but we are a few decades and several technological breakthroughs as well as new discoveries away from coming to what you are talking.

DNA is increasingly used in oncology, but is difficult to interpret elsewhere and in many tumors is not insightful.

> The data to make the correct diagnosis is out there, we just don't have the tools or processing power to use it yet.

Maybe, but we don’t know what or how to measure it.

> If adrenal nodules of similar diameter behave differently, then the tests will inspect more than just diameter.

Everything investigated so far such as: biopsies with histology, MR spectroscopy and measuring the diffusivity of water molecules has not been reliable in differentiating benign or malignant nodules so we still use size. These are nontrivial problems. There are technical limitations to our measuring tools.