Magnetization transfer in fatty and low-fat livers

The magnetization transfer technique was applied to imaging of liver tissue at 0.1 T in order to examine the dependence of proton relaxation parameters on protein concentration. The effect of the fat signal on the values of these parameters was also evaluated by using the special fat/water separation method for low fields. The livers of pigs as a model for low-fat tissue and those of burbots as a model for fatty tissue were examined. For the low-fat liver tissue, the magnetization transfer rate Rwm correlated linearly with the total protein concentration very significantly (p = 0.0086). For the fatty liver, the relaxation parameters did not correlate well with the total protein concentration. After fat/water separation, the relaxation times T1 and T1w, the magnetization transfer rate Rwm and magnetization transfer contrast (MTC), measured from the water image, increased significantly. This indicates that the presence of fat in the liver will affect the measured values of magnetization transfer parameters.