1) Within the blood vessels 
(intra- + L. vasculum vessel) within a vessel or vessels.
Within a vessel or vessels. ... Origin: L. Vasculum = vessel ... (18 Nov 1997) ... 
(in″trә-vas´ku-lәr) within a vessel or vessels.
Type: Term Pronunciation: in′tră-vas′kyū-lăr Definitions: 1. Within the blood vessels or lymphatics.
intravascular Inside a vessel. Cross references of word families related directly, or indirectly, to: 'internal organs, entrails, inside': ent-; enter-; fistul-; incret-; inter-; splanchn-; viscer-.
Given directly into the blood stream.
within the blood vessels.