Effects of refocusing flip angle modulation and view ordering in 3D fast spin echo.
Recent advances have reduced scan time in three-dimensional fast spin echo (3D-FSE) imaging, including very long echo trains through refocusing flip angle (FA) modulation and 2D-accelerated parallel imaging. This work describes a method to modulate refocusing FAs that produces sharp point spread functions (PSFs) from very long echo trains while exercising direct control over minimum, center-k-space, and maximum FAs in order to accommodate the presence of flow and motion, SNR requirements, and RF power limits. Additionally, a new method for ordering views to map signal modulation from the echo train into k(y)-k(z) space that enables nonrectangular k-space grids and autocalibrating 2D-accelerated parallel imaging is presented. With long echo trains and fewer echoes required to encode large matrices, large volumes with high in- and through-plane resolution matrices may be acquired with scan times of 3-6 min, as demonstrated for volumetric brain, knee, and kidney imaging.
Busse
Reed F
RF
GE Healthcare, MR Applied Science Lab, Madison, Wisconsin 53717, USA. reed.busse@ge.com
Brau
Anja C S
AC
Vu
Anthony
A
Michelich
Charles R
CR
Bayram
Ersin
E
Kijowski
Richard
R
Reeder
Scott B
SB
Rowley
Howard A
HA
D000465:Algorithms; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*