Abstract: Flyback imaging is combined with echo planar imaging (EPI) for improved readout flow properties. For increases in imaging time of 50% or less, significant improvements in imaging are realized. The partial flyback improves partial-Fourier EPI and inside-out EPI and can be applied to any EPI trajectory.
Type:
Grant
Filed:
August 14, 1995
Date of Patent:
September 28, 1999
Assignee:
Board of Trustees of the Leland Stanford Junior University
Inventors:
Gerard T. Luk Pat, Craig H. Meyer, John M. Pauly, Dwight G. Nishimura
Abstract: Pulsatile flow is measured using magnetic resonance imaging without cardiac gating using a phase-contrast excitation method to rapidly quantify blood flow and using a spiral k-space trajectory for image data read-out to mitigate deleterious effects of pulsatility. Post-processing of the read-out data provides a cumulative-average velocity plot from which a period of a cardiac cycle is obtained. Time-averaged blood flow rates can be rapidly and robustly measured and is more repeatable than conventional gated techniques.
Type:
Application
Filed:
April 17, 2002
Publication date:
October 23, 2003
Applicant:
THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY
Abstract: A new technique for imaging a material with a high T2/T1 ratio such as articular cartilage uses driven equilibrium Fourier transform (DEFT), a method of enhancing signal strength without waiting for full T1 recovery. Compared to other methods, DEFT imaging provides a good combination of bright cartilage and high contrast between cartilage and surrounding tissue. Both theoretical predictions and images show that DEFT is a valuable method for imaging articular cartilage when compared to spoiled gradient recalled acquisition in the steady-state (SPGR) or fast spin echo (FSE). T2-decay, T1 recovery, echo time, magnetization density, proton density, and equilibrium density per proton are related by a derived equation.
Type:
Grant
Filed:
March 29, 1999
Date of Patent:
April 17, 2001
Assignee:
Board of Trustees of the Leland Stanford Junior
University
Inventors:
Brian A. Hargreaves, Dwight G. Nishimura