MULTI-ECHO SEQUENCE BASED ON ECHO SHIFT PRINCIPLE IN OBSERVATION (PRESTO) Russian patent published in 2017 - IPC A61B5/55 G01R33/56 

FIELD: medicine.

SUBSTANCE: system includes a magnetic resonance imaging device and a display device displaying one or more reconstructed images. The magnetic resonance imaging device includes: a magnet generating a magnetic field B₀, gradient coils applying gradient fields to the field B₀, one or more radio frequency coils generating a radio frequency excitation pulse to excite magnetic resonance and measure the generated gradient echoes, one or more processors configured to drive one or more radio frequency coils to generate a sequence of radio frequency pulses separated by repetition times and induce a magnetic resonance, to control the gradient coils for use after each RF pulse, to receive and demodulate gradient echoes for construction of k-space data lines to reconstruct a plurality of images from the data lines. After each RF pulse, gradient field reading pulses are applied, refocusing the resonance in a plurality of gradient echoes, shifting and refocusing gradient field pulses that shift and refocus at least one echo to a subsequent repetition time. The refocusing gradient field pulses include one or more first gradient field pulses and second gradient field pulse of the opposite polarity has a region A(n+1)/(n)+m, where A is the region of one or more first gradient field pulses, m represents a half of the total region of pulses that cause the gradient echo, and n is the number of repetition times at which a part of the shifted and refocused resonance should be shifted. The method of magnetic resonance imaging is performed by means of a system. The magnetic resonance imaging system comprises a magnetic resonance imaging device, one or more processors configured to drive one or more radio frequency coils generating an RF pulse at the beginning of each plurality of repetition times, to drive the gradient coils to cause at least two gradient echoes through each repetition time, to activate the gradient coils to apply one or more of the first gradient fields shifting at least one gradient echo caused by the current repetition time and to apply one or more second gradient fields refocusing at least one shifted gradient echo through a subsequent repetition time, reconstruct the images from the induced gradient echoes measured by one or more radio frequency coils. The reconstruction includes at least one of the following: T2* maps for visualization as a function of the oxygen level in the body (BOLD), B₀ or a phase map, a diffusion-weighted image (DWI) using the selected gradient echo shifts as diffusion-weighted diffusion gradients, diffusion-tensor imaging (DTI), perfusion/diffusion separation, Q-space or multiple k-space, a sensitivity-weighted image (SWI), which includes phase correction of the map B₀, images with an encoding speed factor (VENC), and an ultra-short echo time (UTE) subtraction from longer echo times.

EFFECT: reduced time of image construction.

16 cl, 8 dwg