A flexible view ordering technique for high-quality real-time 2DFT MR fluoroscopy

Magn Reson Med. 1999 Jul;42(1):69-81. doi: 10.1002/(sici)1522-2594(199907)42:1<69::aid-mrm11>3.0.co;2-y.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Algorithms
  • Blood Flow Velocity / physiology
  • Computer Simulation
  • Echo-Planar Imaging / instrumentation
  • Equipment Design
  • Fluoroscopy / instrumentation*
  • Fourier Analysis
  • Humans
  • Image Enhancement / instrumentation
  • Image Processing, Computer-Assisted / instrumentation*
  • Magnetic Resonance Imaging / instrumentation*
  • Phantoms, Imaging
  • Pulsatile Flow / physiology
  • Sensitivity and Specificity