PASSIVE B1 FIELD SHIMMING Russian patent published in 2016 - IPC G01R33/34 

FIELD: physics.

SUBSTANCE: coil elements (18) generate a B₁ excitation field in an examination region (14), wherein said B₁ excitation field is distorted by patient loading (e.g., wavelength effects). Passive shimming elements (22, 24) are placed between the coil elements and the subject in order to improve the B₁ field uniformity. In one embodiment, passive shimming elements include one or more dielectric rods (55) placed below the subject which generate no substantial MR proton signal and which have a permittivity of at least 100 and preferably greater than 500. In another embodiment, tubes (24) adjacent to each coil element are supplied with a dielectric liquid, wherein the thickness of the dielectric liquid between the coil element and the subject adjusts the phase of the B₁ field generated by the coil element. Active B₁ shimming may be combined with passive shimming elements (22, 24) to achieve an improved RF field homogeneity result.

EFFECT: improving homogeneity of exciting the B₁ excitation field, improving the MR imaging operating process at high field intensity and improved signal-to-noise ratio.

15 cl, 14 dwg