US 12,754,272 B2Granted

Echo planar imaging method capable of reducing image distortion

AssigneeShanghai Jiao Tong University

InventorsZhiyong Zhang, Hao Chen

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Abstract

An echo planar imaging method capable of reducing image distortion is provided. Two radio frequency (RF) pulses α and β are used to respectively flip over a longitudinal magnetization into a transverse plane at different moments, so as to obtain observable transverse magnetization; the transverse magnetization obtained by flipping over the longitudinal magnetization by means of α and β are respectively rephased in two different echo trains by means of gradient pulses. Navigator echo signals are respectively collected before the two gradient echo trains, and the amplitude difference between two gradient echo train signals is corrected on the basis of the amplitude difference between the two navigator echo signals. Correcting the signals collected by the two gradient echo trains, so as to obtain two pieces of image data, and the two pieces of image data are averaged to obtain a final image.

Claims10

Dependent claims

An echo planar imaging method capable of reducing image distortion, based on a first radio frequency (RF) pulse with a flip angle of α, a second RF pulse with a flip angle of β, a spin echo module, as well as a first gradient echo train and a second gradient echo train that are used for collecting echo-planar signals, and specifically comprising the following steps:

step 1:
exciting a first-part magnetization into a transverse plane by using an excitation level of the first RF pulse and keeping a second-part magnetization in a longitudinal plane;
step 2:
after a delay, exciting the second-part magnetization into the transverse plane by using an excitation level of the second RF pulse;
step 3:
applying the spin echo module;
step 4:
rephasing the first-part magnetization by using gradient pulses, and detecting a signal of the transverse first-part magnetization in the first gradient echo train to obtain a first signal;
step 5:
rephasing the second-part magnetization by using gradient pulses, and detecting a signal of the transverse second-part magnetization in the second gradient echo train to obtain a second signal;
and
step 6:
alternately storing the first signal and the second signal along a phase encoding direction to reconstruct k-space, reconstructing sets of image data, and averaging the sets of image data, thereby obtaining a final image, wherein the sets of image data comprise a set of image data reconstructed from a signal of the first gradient echo train and a set of image data reconstructed from a signal of the second gradient echo train.

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