Diagnostic accuracy of transabdominal ultrasound in the detection of acute pancreatitis using contrast-enhanced CT as the reference standard

Abstract

Background: Acute pancreatitis is a common gastrointestinal emergency with increasing global incidence and significant healthcare burden.1,2 Imaging plays a critical role in its diagnosis and management. Although contrast-enhanced computed tomography (CECT) is considered the reference standard, transabdominal ultrasound is widely used as the initial imaging modality owing to its accessibility, cost-effectiveness, and safety profile.3,4

Objective: To determine the diagnostic accuracy of transabdominal ultrasound in detecting acute pancreatitis, using CECT as the reference standard.

Methods: This cross-sectional validation study was conducted at the Department of Radiology, Armed Forces Institute of Radiology and Imaging (AFIRI), Rawalpindi, from January to June 2021. A total of 100 patients aged 15–50 years presenting with clinical suspicion of acute pancreatitis were enrolled via consecutive sampling. All participants underwent transabdominal ultrasound followed by CECT. Diagnostic accuracy parameters—sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy—were calculated using a 2×2 contingency table.

Results: The mean age was 41.09 ± 5.92 years, with male predominance (79%). Ultrasound identified acute pancreatitis in 46 patients, while CECT confirmed 48 cases. Ultrasound demonstrated sensitivity of 79.17% (95% CI: 65.0–89.5%), specificity of 84.62% (95% CI: 72.0–92.7%), PPV of 82.61% (95% CI: 68.6–92.2%), NPV of 81.48% (95% CI: 68.6–90.8%), and overall diagnostic accuracy of 82.00% (95% CI: 73.1–89.0%).

Conclusion: Transabdominal ultrasound demonstrates good diagnostic accuracy and remains a valuable first-line imaging modality for acute pancreatitis, particularly in resource-limited settings. Nevertheless, CECT remains essential for definitive diagnosis and assessment of disease severity.4,5

Keywords: Acute pancreatitis; ultrasonography; computed tomography; diagnostic accuracy; sensitivity; specificity