The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 2003
Filed:
Nov. 20, 2001
David L. Foxall, Mentor, OH (US);
Koninklijke Philips Electronics, N.V., Eindhoven, NL;
Abstract
A steady-state free precession (SSFP) sequence includes a large multiplicity of RF pulses ( ) with a relatively short repeat time or interpulse interval (TR) on the order of 2-10 milliseconds. After applying the RF pulses for a period of about 3 T , about 6 seconds, a steady-state is achieved. Thereafter, at least a phase-encode gradient ( ) and a read gradient ( ) are applied between each subsequent pair of adjoining RF pulses, a data line being generated during each read gradient pulse. For a 128 line image with a TR of 6 milliseconds, a set of data lines are generated in 768 milliseconds, about ¾ of a second. As the data lines are generated, a spectral offset is adjusted by continuously adjusting an RF phase of an RF transmitter ( ) and an RF receiver ( ), with N sets of data lines being generated over 360° of RF phase shift. Like corresponding data lines from each set offset an RF phase by 360°/N are combined and Fourier transformed into an image representation. In this manner, N complete data sets are collected at different spectral offsets without intervening delay intervals to reestablish the steady-state, i.e., in 9 seconds instead of 27 seconds (for N=4).