venogram vs roentgenogram

venogram and roentgenogram both are nouns.

Word	Noun	Adjective	Verb	Adverb
venogram	Yes	No	No	No
roentgenogram	Yes	No	No	No

As nouns, roentgenogram is a hypernym of venogram; that is, roentgenogram is a word with a broader meaning than venogram:

venogram: an X ray of a vein injected with a radiopaque contrast medium
roentgenogram: a radiogram made by exposing photographic film to X rays; used in medical diagnosis

Other hypernyms of venogram include X-ray, X-ray photograph, X-ray picture, X ray.

venogram (noun)	roentgenogram (noun)
an X ray of a vein injected with a radiopaque contrast medium	a radiogram made by exposing photographic film to X rays; used in medical diagnosis