Evaluation of the Pattern of Liver Fat Distribution Using Magnetic Resonance Imaging (MRI) Technique in Patients with Nonalcoholic Fatty Liver Disease

  The aim of this study was to evaluate the spatial distribution of the liver fat with in-phase and out-of-phase gradient echo imaging technique in patients with nonalcoholic fatty liver disease (NAFLD). This cross-sectional prospective study was conducted on 38 volunteers after approval by the Ethics Committee and obtaining informed consent, in the period of more than two years. Inclusion criteria were as being adult with confirmed NAFLD in biopsy findings, and exclusion criteria included pregnancy, alcohol consumption, claustrophobia, history of liver disease, and using lipid control drugs between biopsy and magnetic resonance imaging (MRI). The in-phase and out-of-phase sequences was performed with a 1.5 Tesla scanner. Fat fractions were calculated for different parts of the liver, and compared with each other. Descriptive statistics, linear regression, and a set of Spearman, Kruskul-Wallis, and Mann-Whitney tests were used with a significance level of P < 0.050 in SPSS software. Findings: 38 patients (22 men and 16 women) with mean age of 42.4 ± 10.6 years were investigated. The fat content for segments 1 to 3 (11.63 ± 10.22 percent), superficial (19.00 ± 11.67 percent) and deep (23.01 ± 12.59 percent) regions of segments 4 to 8, superficial region of segment 5 (19.00 ± 11.67 percent), and the whole liver (18.44 ± 11.57 percent) was measured. A direct linear relationship was found between the fat content of the surface region of segment 5 and biopsy findings (R2 = 0.86, P = 0.001). The average fat content of segments 1 to 3 was lower than other anatomical regions (P < 0.050), and the difference in fat content of other groups was not significant (P > 0.050). The spatial distribution of liver fat is heterogeneous in patients with NAFLD.