I would suggest writing a JavaScript script for NiiVue to solve this. 
  https://niivue.github.io/niivue/features...

You can interactively see how using the mouse to different locations updates the text show in the bottom core. The documentation describes a function moveCrosshairInVox() that could automate this:
  https://niivue.github.io/niivue/devdocs/...