Magnetic resonance imaging apparatus and method for measuring irradiation magnetic field

摘要

There is provided an MRI apparatus capable of measuring the B1 distribution of an RF transmission coil in a short time with high accuracy. In order to realize this, imaging means of the MRI apparatus includes a B1 distribution measurement sequence that includes an application of a pre-pulse by RF radiation means and a plurality of signal acquisition sequences with different elapsed time (TI) from the pre-pulse. The signal acquisition sequence uses a pulse having a small flip angle as an RF pulse and is executed before the longitudinal relaxation after the pre-pulse ends. Calculation means calculates the B1 distribution of the RF radiation means using image data with different TI acquired in the respective signal acquisition sequences.

主权项

1. A magnetic resonance imaging apparatus comprising:
an RF radiation unit that radiates a high-frequency magnetic field (B1) to cause nuclear magnetic resonance in an object; an imaging unit that images the object using a B1 distribution measurement sequence that includes a signal acquisition sequence to acquire a nuclear magnetic resonance signal with elapsed time (TI) between (a) application of a high-frequency magnetic field pre-pulse and (b) application of the signal acquisition sequence; and a calculation unit that reconstructs an image of the object using the nuclear magnetic resonance signal, wherein the calculation unit calculates an irradiation magnetic field distribution of the RF radiation unit using a plurality of images with the different elapsed time.