Complex sentence: The film or image of the blood vessels is called an "angiograph", itself can describe both an arteriogram and a venogram, in its everyday usage, the terms angiogram and arteriogram are often used synonymously, whereas the term venogram is used more precisely.
Split into simpler sentences: The film or image of the blood vessels is called an "angiograph", or more commonly, an "angiogram". Though the word itself can describe both an arteriogram and a venogram, in its everyday usage, the terms angiogram and arteriogram are often used synonymously, whereas the term venogram is used more precisely.