Can Radiological Visceral Adiposity Analysis in Acute Pancreatitis Aid in Identifying Underlying Etiology? Assessing the Clinical Potential of Quantitative Radiological Analyses of Visceral Adiposity

Purpose: This study aims to investigate the relationship between visceral adiposity and the possible etiologies of acute pancreatitis. Obesity creates low-grade inflammation and evidence supports an association between obesity and inflammatory conditions such as pancreatitis. CT imaging is utilized in assessing pancreatitis severity and complications but also offers the chance to quantitatively measure visceral fat area (VFA) and subcutaneous fat area (SFA). Given the metabolic role that fat plays, we hypothesized that different body fat distributions, as measured by these areas, may be associated with different etiologies. Further, this also allows us to explore a relationship between severity, etiology, and the fat distributions in patients with acute pancreatitis. Method: Retrospective observational cohort study of all patients admitted to a single center. The VFA, SFA, their ratio (VFA/SFA) and total fat area (TFA) were calculated using a semi-automatic algorithm. Results: 518 patients were admitted with acute pancreatitis over a three-year period. 177 patients underwent CT imaging. Gallstone pancreatitis patients had higher VFA and TFA measurements while alcoholic pancreatitis patients had lower measurements. Patients with pancreatitis with no clear cause had the lowest VFA/SFA ratio. Increasing VFA was associated with increasing severity in a univariate logistic regression model (p = 0.01) but this association diminished in a multivariate model accounting for etiology (p = 0.09). Conclusion: The pattern of fat distribution differs amongst the etiologies of acute pancreatitis, as this likely reflects multiple contributing pathogenic mechanisms. Patients with gallstone pancreatitis had disproportionately more visceral fat, alcohol had the least overall fat, and those without a clear cause had the lowest VFA/SFA ratio. Etiology is strongly associated with body fat distribution. Severity is associated with increased visceral fat, but much less so when etiology is controlled for. The radiological assessment of fat distribution thus can give clues to associated etiology.