| 摘要 |
Magnetic resonance imaging apparatus enabling highly precise spectrum measurement even when resonance frequency changes during MRS or MRSI measurement. When a pulse sequence for suppressing water signals, and an MRS or MRSI pulse sequence are sequentially executed to carry out measurement using repetitive measurement for signal integration or repetitive measurement for phase encoding, signal Sig0 from water is measured with the pulse sequence for suppressing water signals in every repetitive measurement. When the resonance frequency of water deviates from an excitation band region, nuclear magnetization included in water molecules is not excited, so that water signal strength deceases, and therefore change of static magnetic field intensity can be detected by monitoring change of signal Sig0.When water signal strength decreases below a predetermined value, it is determined that resonance frequency has shifted, preliminary measurement for detecting water resonance frequency is performed, and various frequencies are corrected during the repetitive measurement. |
