On the basis of previous research, this subject intends to evaluate the liver improvement of patients with liver disease after weight loss by MRI, and quantify it by extracting features, so as to provide a new method to judge the liver status of patients with liver disease, and to evaluate the correlation between the inflammatory status of patients and the quantitative features of MRI, and try to explain the reasons for the improvement of fatty liver status of patients with liver disease after weight loss. To provide a new theoretical basis for fatty liver and systemic inflammatory liver damage in patients with liver disease after weight loss surgery, and to link them, and try to explain the improvement of fatty liver in patients with liver disease through the reduction of systemic inflammatory level.

This study is a prospective study to explore the improvement of fatty liver and severe state of the whole body in patients with liver disease undergoing weight-loss surgery. The research object is obese patients who underwent laparoscopic sleeve gastrectomy in our hospital. According to the standard of accepting the discharge, about 50 patients were selected and divided into groups according to preoperative, postoperative one month, postoperative three months and postoperative six months.All patients underwent routine sequence examinations using a Siemens 3.0T MRI scanner (MAGNETOM Prisma, Siemens Healthcare, Munich, Germany).This study investigates alterations in NAFLD among patients with obesity who underwent bariatric surgery using MRI-PDFF and MRS techniques. Additionally, we evaluated the factors that may influence these changes in patients after the surgical procedure.

Inclusion Criteria:

• 16 years old < age < 60 years old
• BMI > 32kg/m2
• No previous drinking history; weekly drinking of males < 210g and females < 140g in 12 months
• Preoperative auxiliary examination supports the diagnosis of fatty liver, and liver MRI examination
• Previous attempts to lose weight are ineffective
• Complete case data.

Exclusion criteria:

• Secondary obesity
• History of drinking or excessive drinking (in the past 12 months, male's weekly alcohol intake was ≥210g, female's weekly alcohol intake was ≥ 140g)
• Other diseases causing abnormal liver function
• Body mass index < 28kg/m2
• Poor compliance or self-control, unable to follow the dietary guidance after operation
• Those who cannot complete the follow-up

The major Study Population were who had accept the bariatric surgery.