Accurate fat fraction quantification by multiecho gradient-recalled-echo magnetic resonance at 1.5T in rats with nonalcoholic fatty liver disease.

Aim: To assess the diagnostic accuracy of a new reconstruction technique for gradient-recalled-echo magnetic resonance (MR) sequences that provides a full decomposition of the water and fat content inside a voxel for nonalcoholic fatty liver disease (NAFLD) in rats.

Material And Methods: Rats were randomized into two groups. A control group (n = 10) was given free access to regular dry rat chow for 4 weeks. The steatosis (n = 40) group was given free access to feed and water 4 days per week, and fasted for the remaining 3 days for 4 weeks. All rats were killed at 4 weeks and assessed for fatty infiltration and biochemical method.

Results: The average fat content using the gold standard method was 2.65 g (2.20-3.05) of fat/100g liver for the control group and 4.14 g (1.95-8.60) of fat/100g of liver for the overfed group (p<0.05). The average fat-fraction obtained from the MR was 0.016 (0.01-0.02) for the control group and 0.057 (0.00-0.18) for the overfed group. The Pearson correlation coefficient between the samples was r(2) = 0.87.

Conclusion: Multi-echo MR is a good technique to quantify liver fat in rats.