Three‐point dixon technique for true water/fat decomposition with <i>B</i>₀ inhomogeneity correction

TLDR

Head and body scans often show large B0 shifts near interfaces between air or bone and soft tissue. The study enhances Dixon's technique to enable error‑free water/fat decomposition even under off‑resonance conditions caused by susceptibility differences, demagnetization, or shim errors. The method acquires three images with phase shifts of 0, π, and –π between fat and water, using the third measurement to compute a B0 inhomogeneity map alongside true water and fat images. The technique achieves an SNR equivalent to a 2.7‑NEX acquisition, giving 95 % imaging efficiency, and produces a diagnostically useful B0 map. © 1991 Academic Press, Inc.

Abstract

Abstract An enhancement to Dixon's technique is described which can provide error‐free decomposition of water and fat proton images even in the presence of off‐resonance conditions which result from susceptibility differences, demagnetization, or shim errors. The method uses three measurements with phase shifts of 0, π and − π between the fat and water resonances. The additional information provided by the third measurement is used to calculate an image of the field inhomogeneity in addition to true water and fat images. The signal‐to‐noise ratio (SNR) in the decomposed images is equivalent to that of a 2.7 NEX acquisition (instead of 3 NEX), yielding an SNR imaging efficiency of 95%. In addition, the B 0 image which is provided may have diagnostic value in its own right. Examples of head and body scans often portray surprisingly large B 0 shifts near interfaces between air or bone and soft tissue. © 1991 Academic Press. Inc.