3-DIMENSIONAL FLOW-INDEPENDENT PERIPHERAL ANGIOGRAPHY

A magnetization-prepared sequence, T-2-Prep-IR, exploits T-1, T-2, and chemical shift differences to suppress background tissues relative to arterial blood, The resulting flow-independent angiograms depict vess els with any orientation and flow velocity, No extrinsic contrast agen t is required, Muscle is the dominant source of background signal in n ormal volunteers. However, long-T-2 deep venous blood and nonvascular fluids such as edema also contribute background signal in some patient s. Three sets of imaging parameters are described to address patient-s pecific contrast requirements, A rapid, spiral-based, three-dimensiona l readout is utilized to generate high-resolution angiograms of the lo wer extremities. Comparisons with x-ray angiography and two-dimensiona l time-of-flight angiography indicate that this flow-independent techn ique has unique capabilities to accurately depict stenoses and to visu alize slow flow and in-plane vessels.