A Method for Artifact Correction Due to Demodulation Phase Errors in Magnetic Resonance Imaging

In the process that MR signal is quadrature demodulated, the initial phases of sinusoid and cosinusoid used as demodulation reference signal exist errors, which results in artifacts in the image. It is typically overcome through precise control of the initial phases with the help of the special hardware, but the errors are not reduced completely. In this work, a method based on reference scan is proposed. Reference scan without frequency encoding gradient and phase encoding gradient is executed before FSE sequence, and an echo train is acquired. The phase errors of sinusoid and cosinusoid that are used to demodulate each echo in the reference echo train are calculated. Then the k-space data of image is corrected by these errors and artifacts are removed. The experiments using 0.35T MRI system demonstrate the effectiveness of this method