Combined time-resolved and high-spatial-resolution 3D MRA using an extended adaptive acquisition.
OBJECTIVE
To combine the benefits of time-resolved dynamic imaging and single elliptical centric acquisitions in a reasonable scan time.


METHODS
A time series of images with moderate spatial resolution was acquired using the 3D Time-Resolved Imaging of Contrast KineticS (3D TRICKS) technique with elliptical centric encoding during contrast arrival. Following venous opacification, a complete large centrically encoded k-space volume was acquired. The high-spatial-frequency portions of this volume were combined with a 3D TRICKS time frame to form a high-resolution image. An additional single image is formed by suppressing background and signal averaging all acquired data, including post-venous low-spatial-frequency data. For this image, 2D temporal correlation analysis is used to suppress low-spatial-frequency vein contributions. Arrival time and spatial correlations are used to suppress background.


RESULTS
The 3D TRICKS time frame may be selected to ensure a combined high-resolution image that has optimal central k-space sampling for any vascular region. The single image formed by signal averaging all acquired data has increased contrast-to-noise (CNR) and signal-to-noise (SNR) ratios.


CONCLUSIONS
The advantages of time-resolved and high-spatial-resolution imaging were combined using an extended dual-phase acquisition. Some SNR and CNR gain was achieved by signal averaging. This process is facilitated by background and vein suppression.
Mazaheri
Yousef
Y
Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA. ymazaher@mcw.edu
Carroll
Timothy J
TJ
Du
Jiang
J
Block
Walter F
WF
Fain
Sean B
SB
Hany
Thomas F
TF
Aagaard
Beverly D L
BD
Strother
Charles M
CM
Mistretta
Charles A
CA
Grist
Thomas M
TM
D000818:Animals; D001808:Blood Vessels / Q000033:anatomy & histology; D003287:Contrast Media / Q000008:administration & dosage; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D023421:Models, Animal; D013552:Swine; D013997:Time Factors
D003287:Contrast Media