ABSTRACT: Diagnosis of Chronic Pancreatitis with Endoscopic Ultrasound: A Comparison with Histopathology
André K H Chong MD, FRACP, Joseph Romagnuolo MD,
Brenda Hoffman MD, David Adams MD, David Lewin MD,
Robert Hawes MD
Medical University of South Carolina, SC
Purpose
The diagnosis of early chronic pancreatitis (CP) can be difficult. Endoscopic ultrasound (EUS) has been proposed as a non-invasive and accurate test for CP, with good correlation compared to ERCP, the most commonly used test. However, there is lack of comparative data between EUS findings and the gold standard of histopathology.
The aim of this study was to compare EUS criteria for CP with histopathology from surgical specimens.
Methodology
We retrospectively identified all patients with partial pancreatectomies for presumed CP between 1995-2001 from the MUSC surgical database. Patients were included if EUS was performed within 1 year of surgery. EUS findings were reported by experienced endosonographers at a single centre. Nine criteria were used: 4 parenchymal (hyperechoic foci, strands, lobularity, cysts) and 5 ductal (hyperechoic duct walls, irregular or dilated main duct, visible side branches and calcifications). Pancreatic pathology specimens were reviewed by a single pathologist and given a fibrosis score out of 12 (≥7 represents unequivocal CP). Quantitative ROC curve analysis was performed and Pearson correlation coefficients were calculated.
Results
Eighty-three patients meeting the above inclusion criteria were identified. Twenty were excluded due to incomplete examinations or a diagnosis of a malignancy, leaving 63 eligible patients. Fourteen had distal pancreatectomies, 26 had lateral pancreaticojejunostomies and 23 had pancreaticoduodenectomies. CP was diagnosed histologically in 39/63 (62%). Calcifications were seen in 23/63 on EUS with a sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) for diagnosing CP of 56%, 96%, 96% and 58%, respectively. In patients without calcifications (40), ROC curve analysis revealed that 4 or more EUS criteria provided the best balance of Sn (71%) and Sp (61%). Using a criteria of either calcifications at EUS or ≥ 4 EUS criteria as being diagnostic for CP, the Sn, Sp, PPV and NPV was 87%, 57%, 77% and 72% respectively. Correlation between number of EUS criteria and histologic grade of chronic pancreatitis was low but statistically significant (r=0.29; p=0.02)
Conclusions with implications
This is the largest study to date comparing EUS findings with histopathology as the gold standard in diagnosing CP. Using calcification alone or ≥ 4 EUS criteria provides the best cutoff to make the diagnosis. The use of EUS should be considered early in the algorithm for investigating suspected CP.
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