Medical problem solving begins with observation which results in a number of features (these include salient information in patient history, symptoms listed by the patient, signs elicited during physical examination, and everything that can be demonstrated using instrumental diagnostics). These features are usually caused by one or more conditions, which we have to figure out systematically. If we presume that the patient has a condition, and/or decide to intervene somehow, we can use the same features for monitoring the patient.

Keeping this in mind, we want to understand five things in this subject: how different methods of instrumental diagnostics work, what kind of data they produce, how these data are processedwhich features we can extract from these data, and how we can structure all this precious knowledge. We aim to prove that although the names of the methods may occasionally sound downright scary, their principles of operation are usually elegant and simple.