A filter design method for minimizing ringing in a region of interest in MR spectroscopic images

Magnetic resonance spectroscopic imaging (MRSI) requires a relatively long time to sample k-space (the spatial frequency domain), effectively lowpass filtering the resulting reconstructed image. Ringing is especially problematic when a region of interest (ROI) is close to a bright region outside the ROI, since the bright region tends to create a ringing artifact into the ROI due to the lowpass nature of the data. Here, the authors propose a method that reduces the effect of a stronger signal region on a weaker signal in a nearby ROI by designing a postprocessing filter that steers the strong interference away from the ROI. The proposed method is computationally simple both in the design stage and in applying it to images. The authors present experiments that illustrate the value of the technique.