Multiphase-multistep gadolinium-enhanced MR angiography of the abdominal aorta and runoff vessels.
OBJECTIVE
To optimize three-dimensional gadolinium magnetic resonance angiography (3D-Gd-MRA) of the aorta and runoff vessels by addressing fundamentally different requirements for temporal and spatial resolution in a single semiautomated examination.


METHODS
The technique was designed to obtain pure arterial-phase 3D-Gd-MR angiograms with adequate spatial resolution for each station while avoiding incomplete enhancement due to delayed filling vessels as well as venous overlay. During gadolinium-chelate infusion, a breath-held multiphase 3D-Gd-MRA scan was initiated in the aorta by automatic triggering, followed by automatic table movement. The acquisition was tailored to the vessels of interest by tilting of the 3D volumes. A spatial resolution of 1.7 x 1.2 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 arteries, 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. Correlation to digital subtraction angiography revealed excellent agreement of pathological findings.


CONCLUSIONS
Multiphase-multistep 3D-Gd-MRA reduces the limitations of standard 3D-Gd-MRA techniques with respect to anatomic coverage, spatial resolution, and nonuniform arterial vessel enhancement.
Schoenberg
S O
SO
Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
Londy
F J
FJ
Licato
P
P
Williams
D M
DM
Wakefield
T
T
Chenevert
T L
TL
D000328:Adult; D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D001018:Aortic Diseases / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011859:Radiography
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA