With @Sunderlandkyl we recently added multi-component volume rendering for SlicerHeart (to show B-mode + Doppler images). This is very well applicable to any multichannel images.
The image that you provided had 3 useful channels, the first one seem to be anatomy, while the other second and third have signals in some smaller regions.
I used a gray color transfer function for component 0, some colored ones for 1 and 2, and all transparent for 3 (because it was just a solid block):
There was no need for any data manipulation in Python, it was all done in the GUI.
Up to 4 channels can be rendered like this independently - you can specify opacity and color transfer function for each channel. If you have more channels then you would need to preprocess the data - either select certain channels or combine multiple channels into up to 4 channels that you render independently or as an RGBA color volume.