Contrast-enhanced peripheral magnetic resonance angiography using time-resolved vastly undersampled isotropic projection reconstruction.
OBJECTIVE
To investigate the application of time-resolved vastly undersampled isotropic projection reconstruction (VIPR) in contrast-enhanced magnetic resonance angiography of the distal extremity (single station), and peripheral run-off vasculature in the abdomen, thigh, and calf (three stations).


METHODS
Time-resolved distal extremity imaging was performed using VIPR sequence through the comparison of two acquisition matrix sizes: 256 with TR/TE=3.7/1.4 msec and 320 with TR/TE=4.5/1.8 msec under the same scan time of two minutes. VIPR acquisition was combined with a bolus-chase technique to image the peripheral run-off vasculature. The time-resolved images were reconstructed using a revised sliding window reconstruction filter whose temporal aperture remained narrow for low spatial frequencies and increased quadratically to include all the projection data for high spatial frequencies.


RESULTS
The new temporal filter significantly suppressed the undersampling streak artifacts and venous contamination, while maintaining a high temporal resolution. Both high spatial resolution (ranging from 1.56 x 1.56 x 1.56 mm to 1.25 x 1.25 x 1.25 mm) and high temporal resolution (three seconds per frame) distal extremity images and peripheral run-off images were generated using time-resolved VIPR acquisition, which provides isotropic spatial resolution and isotropic coverage.


CONCLUSIONS
Time-resolved VIPR acquisition was demonstrated to be well suited for distal extremity imaging by providing isotropic spatial resolution, isotropic coverage, and high temporal resolution. The combination of time-resolved VIPR and bolus chase technique provided a novel approach for peripheral run-off examinations.
Du
Jiang
J
Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53792-3252, USA. jiang@mr.radiology.wisc.edu
Carroll
Timothy J
TJ
Brodsky
Ethan
E
Lu
Aiming
A
Grist
T M
TM
Mistretta
Charles A
CA
Block
Walter F
WF
D000005:Abdomen / Q000098:blood supply; D000465:Algorithms; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage*; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D007866:Leg / Q000098:blood supply; D035002:Lower Extremity / Q000033:anatomy & histology / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D012016:Reference Values; D013848:Thigh / Q000098:blood supply; D013997:Time Factors
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA