Non-Invasive, Fast and Reliable Assessment of Age- And Gender-Related Pancreas and Liver Fat Content in Completely Healthy Individuals: Modified Dixon Method with 3 Tesla Magnetic Resonance Imaging

Objective: Acquiring the content of liver fat related to age and gender, and iron signal time as well as fat content values in pancreas and muscle tissue in healthy subjects with normal body mass index (BMI), by using Modified Dixon (mDixon) magnetic resonance imaging. Method: The study enrolled a total of 62 patients aged between 20-62 years including 35 male (56.5%) and 27 female (43.5) patients as healthy liver donors who had normal BMI (18.2 - 25.7 kg/m2) according to Modified Dixon quantification (mDixon quant) sequence in 3 Tesla MR device. Fat content (%) and signal time value for iron (millisecond) in the liver tissue and fat content (%) in pancreas and muscle tissue were automatically quantified in the relevant areas through images. For normalization, muscle tissue was measured for the value of iron signal time. Liver segment VI, head, body and tail parts of pancreas, and two paraspinal muscles (multifidus) in the same section were quantified. Multivariate generalized linear models were used to test significant differences in fat contents and iron signal time values between age subgroups. Results: Mean fat content in the liver was measured as 3.06 ± 1.06% with value of iron signal time as 23.32 ± 3.27 msec, and mean fat content in the pancreas was measured as 2.87 ± 1.67%, mean fat content in the muscle tissue as 3.62 ± 2.04% and value of iron signal time as 27.58 ± 3.16 msec. Mean liver fat content did not show a significant difference between female (2.89 ± 1.19) and male patients (3.19 ± 0.94) (p-value: 0.252 / 0.936). Differences in liver fat contents between age subgroups were not significant for female vs. male patients (2.91 ± 0.88 vs. 2.82 ± 0.90 (20- 29 years), 2.69 ± 1.77 vs. 3.24 ± 0.81 (30-39 years), 2.56 ± 1.00 vs. 3.21 ± 1.09 (40-49 years) and 3.37 ± 1.44 vs. 3.42 ± 0.99 (50-62 years). While there was a positive correlation between the age and fat contents in pancreas (r=0.385, p=0.022) and muscle (r=0.697, p=0.001) in male patients, a positive correlation was seen only between age and muscle fat content in female patients (r=0,458, p=0,016). Along with BMI values within normal range, BMI was found to be positively correlated with liver (r= 0.382, p=0.024) and muscle fat contents (r=0.380, p=0.024) only in male patients. A mild negative correlation (r=-0,420, p=0.029) and a strong negative correlation (r=-0,617, p=0.001) were seen in women and men, respectively, between mean fat content and iron signal time of liver. There was a mild positive correlation between liver fat content and muscle fat content in men (r=0,409, p= 0.015).