Data retrieval systems for retrieving data from a multidimensional medical data set include: (a) a client configured to electronically request image data of a patient; (b) a server in communication with a plurality of electronically stored multidimensional patient medical image data sets; and (c) a data retrieval interface in communication with the client and the server. The data retrieval interface is configured to retrieve image data from the multidimensional data sets. The respective data sets have a number of grid points in G dimensions and a number of values V for each grid point. Some of the data sets have different G dimensions and V values than others. The data retrieval interface is configured to employ an object oriented retrieval process. The client can employ and Image region object to request data and the interface can employ a Physical region object that defines a multi-dimensional region extent associated with a client request for data on a region of interest to retrieve relevant image data from a respective patient data set. Related signal processor circuits, computer programs and data structures for data retrievals are also described.