Association between novel MRI-estimated pancreatic fat and liver histology-determined steatosis and fibrosis in non-alcoholic fatty liver disease

Background Ectopic fat deposition in the pancreas and its association with hepatic steatosis have not previously been examined in patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD). Aim To quantify pancreatic fat using a novel magnetic resonance imaging (MRI) technique and determine whether it is associated with hepatic steatosis and/or fibrosis in patients with NAFLD. Methods This is a cross-sectional study including 43 adult patients with biopsy-proven NAFLD who underwent clinical evaluation, biochemical testing and MRI. The liver biopsy assessment was performed using the NASH-CRN histological scoring system, and liver and pancreas fat quantification was performed using a novel, validated MRI biomarker; the proton density fat fraction. Results The average MRI-determined pancreatic fat in patients with NAFLD was 8.5% and did not vary significantly between head, body, and tail of the pancreas. MRI-determined pancreatic fat content increased significantly with increasing histology-determined hepatic steatosis grade; 4.6% in grade 1; 7.7% in grade 2; 13.0% in grade 3 (P=0.004) respectively. Pancreatic fat content was lower in patients with histology-determined liver fibrosis than in those without fibrosis (11.2% in stage 0 fibrosis vs. 5.8% in stage 12 fibrosis, and 6.9% in stage 3-4 fibrosis, P=0.013). Pancreatic fat did not correlate with age, body mass index or diabetes status. Conclusions In patients with NAFLD, increased pancreatic fat is associated with hepatic steatosis. However, liver fibrosis is inversely associated with pancreatic fat content. Further studies are needed to determine underlying mechanisms to understand if pancreatic steatosis affects progression of NAFLD.