Research in Magnetic Resonance Imaging (MRI) requires researchers to make changes to the software that controls the scanner. Thus, the first challenge faced by MRI researchers is to understand the scanner's code to find the places where the changes must be made, and to make sure that the changes will not produce undesired effects in other parts of the code. At the Biomedical Imaging Center at Pontificia Universidad Católica de Chile, we have been developing visualization tools for analysing the Philips scanner's code, and for storing and sharing the know-how thus acquired. We devised the tools to help MRI researchers identify the code's main concerns and understand how these concerns are represented and handled within the code. In this paper we report on the tools' functionalities; e.g., finding the places where each object or function is used, analyzing relationships among objects, storing comments to objects and functions, identifying which functions are executed and in which order, representing this information as a tree, searching this tree for a given function, and highlighting the differences between the trees representing two different executions. Initial tests show that these tools effectively support MRI researchers in their task of understanding the scanner's code.