Findings on Endoscopic Retrograde Cholangiopancreatography and Pancreatic Function Test in Suspected Chronic Pancreatitis and Negative Cross-Sectional Imaging

Abstract

The diagnosis of chronic pancreatitis (CP) often relies on cross-sectional imaging, which may be insensitive for early disease. The aim of this study was to assess the utility of cholecystokinin pancreatic function test and endoscopic retrograde cholangiopancreatography (ERCP) for the diagnosis of CP in patients with negative or inconclusive cross-sectional imaging. Consecutive patients with suspicion of CP and negative or inconclusive cross-sectional imaging (computerized tomography and magnetic resonance cholangiopancreatography) were evaluated with cholecystokinin-stimulated endoscopic pancreatic function test (ePFT) and ERCP. The setting was a referral center for difficult diagnostic scenarios. Pancreatograms were scored according to Cambridge classification (I-IV). The ePFT was used to determine the peak lipase concentration in pancreatic juice during timed duodenal aspiration. The gold standard for the diagnosis of CP was long-term clinical follow-up evaluation. Thirty-five patients met the study criteria. The median duration of follow-up evaluation was 7 years (25th, 75th percentiles: 3, 7). Twenty-four of the 35 patients were diagnosed with CP based on long-term follow-up evaluation with a clinical composite reference standard. The sensitivity, specificity, and positive and negative predictive values were 96%, 37%, 77%, and 80% for ePFT and 71%, 91%, 94%, and 59% for ERCP, respectively. A low peak lipase concentration on the initial ePFT was associated with development of steatorrhea during the follow-up period (P = .02). ePFT is a sensitive test for the diagnosis of patients with suspicion of CP and negative or inconclusive cross-sectional imaging. ERCP has modest sensitivity and high specificity for this purpose. A normal ePFT rules out CP with a high degree of certainty. An abnormal test result requires follow-up evaluation and diagnostic confirmation.