Abdominal magnetic resonance imaging assessment and quantification of pancreatic and liver adipose tissues in obesity before and after laparoscopic sleeve gastrectomy

Objectives: To investigate the changes of liver and pancreas fat fraction after laparoscopic sleeve gastrectomy (LSG) by magnetic resonance imaging (MRI).Methods: Our study included morbid obesity with normal blood glucose and underwent abdominal MRI before and after LSG. In total, 21 patients were included, 10 underwent abdominal MRI before and 3 months after LSG, 11 underwent abdominal MRI before and 1-2 years after LSG. Liver fat fraction (LFF), pancreas fat fraction(PFF) were measured on proton density fat fraction (PDFF) maps at different time points. Fasting blood samples were collected for measurement of triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), plasma glucose and insulin levels. Homeostasis model assessment (HOMA) was used to evaluate insulin resistance (HOMA-IR). Pearson correlation was used to analyze the correlation between different parameters.Results: LFF and PFF were significantly decreased at 3 months and 1-2 years after LSG along with weight loss, decreased body mass index (BMI) and waist circumference. Though these parameters showed a decreasing trend from 3 months to 1-2 years, but there was no statistical difference. 81.0% patients had fatty liver and 38.1% patients had fatty pancreas at baseline. However, all patients had no fatty liver at 3 months and no fatty pancreas at 1-2 years after LSG. HDL levels were increased, but LDL, TG and insulin levels were decreased 1-2 years after LSG but not at 3 months. LFF was related to fasting insulin and HOMA-IR at baseline but not after LSG. There was no association of PFF with fasting plasma glucose, fasting insulin or HOMA-IR, but & UDelta;PFF was related to & UDelta;insulin and & UDelta;HOMA-IR at 1-2 years after LSG.Conclusion: Changes of liver and pancreas fat content in obesity before and after LSG can be quantified by IDEAL -IQ. Treatment with LSG can reverses fatty liver and fatty pancreas in obese patients. In addition, the lipid profile and insulin sensitivity are also improved after LSG along with the decreased of LFF and PFF.