Multiphase-multistep gadolinium-enhanced MR angiography of the abdominal aorta and runoff vessels

RATIONALE AND OBJECTIVES. TO optimize three-dimensional gadolinium magnetic resonance angiography (3D-Gd-MRA) of the aorta and runoff vessels by addre ssing fundamentally different requirements for temporal and spatial resolut ion in a single semiautomated examination. METHODS, The technique was designed to obtain pure arterial-phase SD-Gd-MR angiograms with adequate spatial resolution for each station while avoiding incomplete enhancement due to delayed filling vessels as well as venous ov erlay. During gadolinium-chelate infusion, a breath-held multiphase 3D-Gd-M RA scan was initiated in the aorta by automatic triggering, followed by aut omatic table movement, The acquisition was tailored to the vessels of inter est by tilting of the 3D volumes, A spatial resolution of 1.7 x 13 x 0.8 mm in the calves was achieved by use of elliptical-centric k-space reordering . Signal-to-noise ratio was maximized with a 12-element peripheral vascular coil. Twelve patients with peripheral vascular disease were studied, RESULTS. In cases of aortic occlusive disease (n = 2), dissections (n = 3), or aneurysms (n = 4), substantially delayed fill-in of reconstituted arter ies, false lumens, or aneurysmal segments occurred, which was detected only on the later 3D-Gd-MRA phase. High-resolution arterial-phase scans in the calves were obtained, with only one case of substantial venous overlay. Cor relation to digital subtraction angiography revealed excellent agreement of pathological findings, CONCLUSIONS, Multiphase-multistep 3D-Gd-MRA reduces the limitations of stan dard 3D-Gd-MRA techniques with respect to anatomic coverage, spatial resolu tion, and nonuniform arterial vessel enhancement.