A Novel MRI Adiabatic T₂ Preparation Sequence with Reduced B1 Sensitivity

This invention relates to a novel magnetic resonance angiography (MRA) method that accomplishes uniform contrast enhancement between coronary arteries and the surrounding tissue across the entire imaging volume. The disclosed technique utilizes an adiabatic refocusing transverse relaxation time (T₂)-preparation pulse sequence, in which the magnetization is tipped into the transverse plane with a hard radio-frequency (RF) pulse and refocused using a pair of adiabatic fast-passage RF pulses. The isochromats are subsequently returned to the longitudinal axis using a hard RF pulse. Simulations and in vivo images acquired with the T₂-Prep sequence illustrate excellent suppression of artifacts originating from B₁ inhomogeneity while achieving contrast-to-noise (CNR) enhancement between coronary arteries and surrounding tissues. Furthermore, images acquired with the T₂-Prep sequence show suppression of the banding artifacts and improvement of the visual sharpness of distal segments of the coronaries as compared to images acquired without the T₂-Prep sequence.