Dual Double-gradient-echo MRI for Liver Fat Content Analysis

We have devised a modified Dixon method for analyzing fatty infiltration of the liver using a dual double-gradient-echo (DDGRE) sequence. To correct the T2* decay, fourfold echo images were obtained by out-of-phase (TE = 2.3/6.9 ms) and in-phase (4.6/9.2 ms) double-echo sets during a single breath-hold scan on a 1.5 T MRI. The liver fat fractions obtained using the DDGRE method were determined in patients with fatty liver and in healthy volunteers as controls. Moreover, the fat fractions determined in vitro using the DDGRE method were compared with those determined by the conventional double-gradient-echo method, other MRI methods, and X-ray CT. The average fat fractions in patients with fatty liver obtained with the DDGRE method was over 10%, and was significantly greater than those in healthy volunteers. The fat fraction of the phantom obtained with the DDGRE method showed the closest agreement with the actual fat content. The DDGRE method with a single breath-hold makes it possible to simply and accurately analyze fatty infiltration of the liver.