Background Recent studies have highlighted the correlation between diabetes and pancreatic fat infiltration. Notably, pancreatic fat content (PFC) is a potential biomarker in diabetic patients, and magnetic resonance imaging (MRI) provides an effective method for noninvasive assessment of pancreatic fat infiltration. However, most reports of quantitative measurement of pancreatic fat have lacked comparisons of pathology results. The primary objective of this study was to determine the feasibility and accuracy of pancreatic MRI by using pancreatic fat fraction (PFF) measurements with the IDEAL-IQ sequence; the secondary objective was to explore changes in PFC between pigs with and without diabetes. Methods In this prospective study, 13 Bama Mini-pigs (7 females, 6 males; median age, 2 weeks) were randomly assigned to diabetes ( n = 7) or control ( n = 6) groups. Pigs in the diabetes group received high fat/high sugar feed, combined with streptozotocin injections. At the end of 15 months, biochemical changes were evaluated. All pigs underwent axial MRI with the IDEAL-IQ sequence to measure PFF; PFC of fresh pancreatic parenchyma was measured by the Soxhlet extraction method; and pancreatic fat distribution was observed by histopathology. Results of all analyses were compared between the diabetes and control groups by using the Mann-Whitney U-test. Correlations of PFF and PFC, fasting blood glucose (GLU), and serum insulin (INS) were calculated by using the Spearman correlation coefficient. Single-measure intraclass correlation coefficient (ICC) was used to assess interreader agreement. Results There were significant differences between diabetes and control groups: GLU (mmol/L) was 18.06 ± 6.03 and 5.06 ± 1.41 ( P < 0.001); INS (mU/L) was 21.59 ± 2.93 and 29.32 ± 3.27 ( P = 0.003); PFC (%) was 34.60 ± 3.52 and 28.63 ± 3.25 ( P = 0.027); and PFF (%) was 36.51 ± 4.07 and 27.75 ± 3.73 ( P = 0.003). There was a strongly positive correlation between PFF and PFC (r = 0.934, P < 0.001); there were moderate correlations between PFF and GLU (r = 0.736, P = 0.004; positive correlation), and between PFF and INS (r = − 0.747, P = 0.003; negative correlation). Excellent interreader agreement was observed for PFF measurements (ICC, 0.954). Conclusions Pancreatic fat infiltration shows a clear association with diabetes. MRI with the IDEAL-IQ sequence can be used to accurately and reproducibly quantify PFC.

Background Recent studies have highlighted the correlation between diabetes and pancreatic fat infiltration. However, pancreatic fat content (PFC) is rarely confirmed by pathological results, and a change of PFC during progression of type 2 diabetes (T2DM) is currently controversial. Purpose To evaluate the relationship of MRI‐pancreatic proton density fat fraction to serologic changes and histology in an experimental model of diabetes. Study Type Prospective animal study. Animal Model Thirteen Bama pigs were randomly assigned to diabetes (n = 7) or control (n = 6) groups. Pigs in the diabetic group received high‐fat/high‐sugar feed, combined with three doses of streptozotocin injections. Field Strength/Sequence 3.0T, IDEAL‐IQ sequence. Assessment Starting in the fifth month, biochemical changes were evaluated; all pigs underwent axial MRI with the IDEAL‐IQ sequence to measured pancreatic fat fraction (PFF). PFC was measured by the Soxhlet extraction method. Pancreatic fat distribution and pancreas islet morphology were observed by histopathology. Statistical Tests A Mann–Whitney U‐test, independent‐samples t‐test, Pearson correlation, Spearman correlation, single‐measure intraclass correlation coefficient (ICC) were performed. Results During the development of T2DM, the PFF, weight, fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TCHO), low‐density lipoprotein (LDL), and HOMA‐IR (insulin resistance) of the experimental group showed an upward trend; fasting insulin (INS), high‐density lipoprotein (HDL), and HOMA‐β showed decreasing trends. At the end of the fifteenth month, FBG (mmol/L) was 18.06 ± 6.03 and 5.06 ± 1.41 (P < 0.001), PFF (%) was 36.52 ± 4.07 and 27.75 ± 3.73 (P = 0.002), INS (mU/L) was 21.59 ± 2.93 and 29.32 ± 3.27 (P = 0.001), HOMA‐IR was 16.83 ± 4.22 and 6.70 ± 2.45 (P < 0.001), HOMA‐β was 1.50 ± 0.24 and 2.77 ± 0.45 (P < 0.001), between the experimental and control groups. There were strong and moderate positive correlations between PFF and PFC (r = 0.968, P < 0.001), and FBG (r = 0.657, P = 0.015), and HOMA‐IR (r = 0.608, P = 0.028). Data Conclusion MRI‐proton density fat fraction can measure the fat content of the pancreas with great accuracy and repeatability; PFF is a potential biomarker that can reflect the different stages of diabetes development. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1905–1913.

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