Quantitative assessment of abdominal ectopic fat deposits in patients with different glucose tolerance by using mDixon Quant MRI

This study aimed to quantitatively analyze the characteristics of abdominal ectopic fat deposition in patients with different glucose tolerance by using mDixon Quant MRI. A total of 98 patients and 38 healthy volunteers were included in this study. The patients were stratified as impaired glucose tolerance (IGT) group (n = 18), the duration of diabetes less than 5 years (DMa group, n = 31) and longer than 5 years(DMb group, n = 49). The fat fraction (FF) of left hepatic lobe, right hepatic lobe, whole liver, pancreatic head, pancreatic body, pancreatic tail, spleen, kidney, as well as L3 vertebra, psoas muscle, the total abdominal fat area(S1), intra-abdominal fat area (S2) and S3 (S2/S1) were measured and calculated separately. Analysis of variance, correlation analysis, paired sample t-test, Welch's ANOVA, ROC curve and ordered multivariate logistic regression were performed for statistical analyses. The difference in BMI and weight among the four groups were statistically significant (P < 0.001). The metabolic parameters were statistically significant among three patients groups (P < 0.05). The differences in FF values of left hepatic lobe, right hepatic lobe and whole liver, spleen, pancreatic head, pancreatic body and pancreatic tail, L3 vertebra, psoas muscle, S1, S2 and S3 were statistically significant among the four groups (P < 0.001). The FF values of L3 vertebra and the pancreatic tail had the higher diagnostic efficacy when assessing the presence and extent of impaired glucose tolerance, respectively. For each percentile increased in the FF value of the L3 vertebra, the risk of diabetes entering the next stage increases 16%. Different organs in the abdomen have different sensitivity to fat deposition. The liver and pancreas have uneven distribution of fat deposits in people with different glucose tolerance. However, ectopic fat deposition do not change significantly with the duration of the disease. The FF value of L3 vertebra is a sensitive imaging index in patients with different glucose tolerance.