THE EFFECTS OF TIME-VARYING INTRAVASCULAR SIGNAL INTENSITY AND K-SPACE ACQUISITION ORDER ON 3-DIMENSIONAL MR-ANGIOGRAPHY IMAGE QUALITY

The optimum infusion timing ana k-space ordering for obtaining gadolin ium-enhanced three-dimensional MR angiograms was determined through co mputer modeling using temporal contrast characteristics obtained from patient, gadolinium infusion data,The effects of bolus timing were eva luated by varying the relationship between peak intravascular gadolini um concentration and the time at which the center of k space was acqui red (t(ck)) for sequential and centric acquisition techniques, Flow ph antom experiments were performed to validate the theoretical computati ons, Gadolinium concentration at the time of central k space acquisiti on determines intravascular signal intensity, Artifacts, including ves sel broadening and edge ringing, depend On the order in which k space is collected and oil how rapidly the gadolinium concentration changes, Artifacts are greatest when the center of k space is acquired before the intravascular gadolinium peak. Application of the optimal infusion timing results in preferential arterial enhancement with a minimum of artifacts in patients undergoing MR angiography.