Linear Phase Shift Correction for Field Map Estimation with Bipolar Gradient Dual-Echo Sequence Using the Noise PDF

Hiroyuki Takeda¹, Boklye Kim²

We propose a field map acquisition method using a dual-echo fast field echo (DEFFE) sequence. It is advantageous that the DEFFE sequence measures an image pair with different echo times simultaneously. Consequently, there is little displacement between the images unlike the image pair measured by two separated echo sequences. However, the DEFFE introduces linear phase errors to the image pair. In this work, we present an appropriate probability density function (PDF) of nonuniform noise in the field map. Our phase correction method derived from the PDF properly removes outliers and works fine even in the presence of the wrapping effects.