http://www.web3d.org/x3d/content/examples/Basic/VolumeRendering/
the nrrd images seem to be in the savage url
https://savage.nps.edu/Savage/VolumeRendering/datasets/nrrd/supine.nrrd
and any back links to the x3d scene, are simply in /VolumeRendering ie:
http://www.web3d.org/x3d/content/examples/Basic/VolumeRendering/EdgeBrain.x3d

H3D displays most of them well, except:
CartoonBackpack
ComposedBackpack

https://x3dom-nrrd.glitch.me/index.xhtml
- x3dom can do ImageTexture3D by specs
- (it also has vicomtech 3D rendering, not web3d specs)