Shortest Path Search in 4-dimensional Circle Hough Room - get graph from matrix

Hi, I'm currently working on a Softwareproject for my Studies. The goal ist to get the Exact Segmentation of the two heart arteries in a set of CT data. The data is one slice with the time as third dimension. The User ist supposed to select the two arteries in the first and the last Slide, then the algorithm should compute their exact progression over the time. Since the Arteris appear circular it is possible to use the Circular Hough Transformation for this. I used imfindcircles for the search of possible circles for the selection and it works great.

Now my Problem: For the progress over the time I'd like to use a shortest Path search algorithm. I know that Matlab offers some. but only for Graphs. Since the search should happen in the Circular Hough Room, I'd have to convert the whole 4-D-Matrix to a Graph. I haven't found anything similar on the web, so my question: Is there an easy way to convert an 4-D-Matrix into a Graph? If there is: Is it also possible to define the weight in dependency from the coordinates of the cirlecenter and the radius compared to the start point? Or does maybe somebody know a smoother way to do the search?

It would really help me, if someone had an idea how to do it. Thanks in advance Aerl