Back to results
US 12,372,595 B2Granted
Multi-echo radio frequency (RF) based spatial encoding in magnetic resonance imaging using frequency-modulated RF pulses
AssigneeRegents of the University of Minnesota
InventorsMichael Garwood, Efraín Torres, Taylor Froelich
Life of this patent
Estimating the term…
Abstract
Multi-echo radio frequency (“RF”) gradient based magnetic resonance imaging (“MRI”) is described. A gradient is established in the B1 RF field to enable B1-encoded pulse sequences, such as B1-encoded spin-echo pulse sequences. As a non-limiting example, the B1-field gradient can be established using a multi-echo frequency-modulated Rabi encoded echoes (“ME-FREE”) technique.
Claims25
A method for magnetic resonance imaging, the method comprising:
- (a) acquiring magnetic resonance data from a subject using a magnetic resonance imaging (MRI) system by:
- generating a pulse sequence with the MRI system, the pulse sequence comprising:
- a radio frequency (RF) excitation pulse;
- a train of frequency-modulated RF pulses comprising at least:
- a first frequency-modulated RF pulse having a first time-bandwidth product, wherein the first frequency-modulated RF pulse is generated after the RF excitation pulse;
- a second frequency-modulated RF pulse having a second time-bandwidth product, wherein the second frequency-modulated RF pulse is generated after the first frequency-modulated RF pulse;
- a plurality of frequency-modulated RF pulses generated after the second frequency-modulated RF pulse and each having a third time-bandwidth product;
- acquiring magnetic resonance data with the MRI system by sampling magnetic resonance signals formed in multiple echoes in response to the RF excitation pulse, wherein a phase whose value is dependent on the first time-bandwidth product and the second time-bandwidth product and the plurality of frequency-modulated RF pulses is imparted to magnetic resonance signals formed in response to the RF excitation pulse, and a difference between the first time-bandwidth product and the second time-bandwidth product is changed at least one of within the pulse sequence or in repetitions of the pulse sequence in order to phase encode the magnetic resonance data;
- (b) reconstructing an image from the acquired magnetic resonance data.
6 more elements
A method for magnetic resonance imaging, the method comprising:
- (a) acquiring magnetic resonance data from a subject using a magnetic resonance imaging (MM) system to generate a pulse sequence that phase encodes the magnetic resonance data by imparting a phase to magnetic resonance signals by applying a series of frequency-modulated radio frequency (RF) pulses to the subject to form multiple echoes in each repetition of the pulse sequence, wherein at least one of the plurality of frequency-modulated RF pulses has a variable time-bandwidth product relative to other ones of the plurality of frequency-modulated RF pulses, thereby defining an R-difference value between at least two of the frequency-modulated RF pulses, which causes the phase to be imparted to the magnetic resonance signals;
- and
- (b) reconstructing an image from the acquired magnetic resonance data.
Dependencies are inferred from the claim text.