Imaging manipulation was performed using Horos, which can be downloaded from at no cost to the user. The program automatically loads digital imaging in communications in medicine (DICOM) files when a CD/DVD is inserted into the computer, or DICOM files can be imported manually from flash drives. The default 2D viewer allows basic tasks such as viewing, magnifying, and manipulating the window level of the images, and can also be used for more advanced functions such as performing exact measurements (even those involving curved surfaces) and marking regions of interest (ROIs), which are used for computing volumes and creating tumor models. On the other hand, the 3D viewer can be used to create 3D models of patients and perform virtual craniotomies that are suitable for preoperative planning.
In the initial version of the plugin, only the fast model-free deconvolution algorithm was implemented . Since, we implemented several other models the GUI was extended. Thereby, care was taken to not overload the interface so that the user can easily work with the software.
Besides the technical (implementation of the algorithms) and medical/physiological (modeling the perfusion in tissue) aspects of this software, another part of this software is quality management. On the one hand, this comprises testing and evaluation but also documentation of the software to allow for certification of the software for clinical use. The UMMPerfusion plugin was certified in-house according to the German Medical Product law. Besides the necessary documents, e.g., risk analysis etc., we designed a testing scheme and corresponding reference datasets  to continually evaluate changes to the software. In addition, we also provide a bug tracking system so that user can report errors or problems with the software but also suggestions of new features. All of this is provided via an online platform called OpossUMM ( ) which is freely accessible. 2b1af7f3a8