CT-Measured Fat & Muscle Parameters: Impact on Acute Pancreatitis Severity

Abstract

Aim: This study investigated whether Computed Tomography (CT)-measured abdominal fat and muscle parameters could improve the accuracy of acute pancreatitis (AP) severity assessment using the CT severity index (CTSI). Methods: This retrospective study included clinical and imaging parameters of 87 patients with AP. Asan J-Morphometry (Seoul, Korea), an ImageJ-based software (NIH, USA), was used to quantify abdominal muscle and fat areas. Total CTSI score, total fat area (TFA), superficial fat area (SFA), visceral fat area (VFA), total muscle area (MA) and total muscle-fat area (MFA) were calculated. Interreader agreement assessments, univariate and multivariate analyses were performed. Results:No significant differences were found in CT measurements between groups with or without systemic or local complications, or between groups categorized as mild and severe based on total CTSI scores (p > 0.05 for all comparisons). Surgery, systemic complications, and a high total CTSI score significantly increased the risk of local complications, with odds ratios of 0.001, 141.9, and 2.42, respectively. With a cutoff of 4 or higher total CTSI score, the diagnostic performance of CTSI in assessing AP severity was as follows: sensitivity 81.25% (95% CI: 63.6-92.8), specificity 49.09% (95% CI: 35.4-62.9), positive predictive value 51% (95% CI: 42.7-59.2), negative predictive value 90% (95% CI: 74.8-96.5), and area under the ROC curve (AUC) 0.72 (95% CI: 0.61-0.81) (p < 0.001). The intraclass correlation coefficients (ICC) were ≥ 0.90 between the readers. Conclusions: In this study, CT-measured fat and muscle parameters did not significantly improve the accuracy of CTSI in predicting severity of AP.