Thanks for referencing that paper. It's an interesting read and highlights a great use-case for the RT Box.
My understanding after reading the paper is that the Elsys TraNET instrument is simply used to record data. Per Section 3.3 of the paper, the "collected measurements are exported for processing which is done using MATLAB". It does not seem to suggest that the impedance analysis is performed in real-time or by the TraNET software.
A similar workflow would be possible without the Elsys TraNET instrument by recording the time-domain data on the RT Box using the Scope, Data Capture block, or To-File block, and then processing that offline on a desktop using MATLAB or a similar tool. Performing this calculation on the RT Box hardware itself in real-time would generally be quite computationally intensive, so I would expect the offline approach to be preferable in most instances.