Accelerating time-resolved MRA with multiecho acquisition.
A new four-dimensional magnetic resonance angiography (MRA) technique called contrast-enhanced angiography with multiecho and radial k-space is introduced, which accelerates the acquisition using multiecho while maintaining a high spatial resolution and increasing the signal-to-noise ratio (SNR). An acceleration factor of approximately 2 is achieved without parallel imaging or undersampling by multiecho (i.e., echo-planar imaging) acquisition. SNR is gained from (1) longer pulse repetition times, which allow more time for T(1) regrowth; (2) decreased specific absorption rate, which allows use of flip angles that maximize contrast at high field; and (3) minimized effects of a transient contrast bolus signal with a shorter temporal footprint. Simulations, phantom studies, and in vivo scans were performed. Contrast-enhanced angiography with multiecho and radial k-space can be combined with parallel imaging techniques such as Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) to provide additional 2-fold acceleration in addition to higher SNR to trade off for parallel imaging. This technique can be useful in diagnosing vascular lesions where accurate dynamic information is necessary.
Jeong
Hyun J
HJ
Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.
Eddleman
Christopher S
CS
Shah
Saurabh
S
Seiberlich
Nicole
N
Griswold
Mark A
MA
Batjer
H Hunt
HH
Carr
James C
JC
Carroll
Timothy J
TJ
D003198:Computer Simulation; D003287:Contrast Media; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019047:Phantoms, Imaging; D013997:Time Factors
D003287:Contrast Media