A flexible view ordering technique for high-quality real-time 2DFT MR fluoroscopy.
A method to tailor the view order to the reconstruction cycle is introduced for real-time MRI. It is well known that view sharing and oversampling central k-space views can improve the temporal resolution of gradient-echo pulse sequences. By ordering phase-encodes to synchronize k-space acquisition with the reconstruction cycle, apparent temporal resolution can match the frame rate with as few as one-fourth of the phase-encodes sampled per reconstruction. Spatial resolution is maintained by periodically updating high spatial frequencies. In addition to apparent temporal resolution, three other criteria for real-time imaging are identified and evaluated: display latency, dispersion, and frame-to-frame consistency. Latency is minimized by ordering views in a reverse-centric manner within each reconstruction interval, sampling high-energy views immediately prior to beginning reconstruction. Dispersion is kept low and consistent by synchronizing acquisition and reconstruction, thus avoiding poorly timed reconstruction instances. Real-time implementation demonstrates pulsatile time-of-flight blood signal enhancement in humans.
Magnetic Resonance Laboratory, Mayo Clinic, Rochester, MN 55905, USA.
R F
RF
Busse
D G
DG
Kruger
J P
JP
Debbins
S B
SB
Fain
S J
SJ
Riederer
D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D017352:Echo-Planar Imaging / Q000295:instrumentation; D004867:Equipment Design; D005471:Fluoroscopy / Q000295:instrumentation*; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011673:Pulsatile Flow / Q000502:physiology; D012680:Sensitivity and Specificity