EUS and chronic pancreatitis: seeing is believing?

Significance of normal appearance on endoscopic ultrasonography in the diagnosis of early chronic pancreatitis

Background and Objectives:

The Rosemont classification (RC) was developed as a consensus-based standard for the diagnosis of chronic pancreatitis (CP) by endoscopic ultrasonography (EUS), however, it is more complicated than the conventional scoring system. We have noticed that in the early stages of CP, it is not unusual to observe pancreas with abnormal appearance coexisting with the areas of normal parenchyma. The aim of this study was to investigate the validity of a “normal” pancreas appearance and to evaluate the usefulness of modified diagnostic criteria in comparison to the traditional EUS criteria and the RC.

Patients and Methods:

One hundred and seventy-seven patients who had undergone both EUS and endoscopic retrograde pancreatography (ERP) within 2 months were enrolled in the study, and patients with pancreatic cancer were excluded from the study. ERP findings were used as the gold standard for the diagnosis of CP. The EUS images obtained were classified according to both the RC and our new modified criteria. The latter includes an additional criterion to the modified traditional criteria: fine-reticular pattern (F-RP) was defined as a normal pancreatic parenchyma. We compared the accuracy between the new modified EUS criteria and the RC.

Results:

(1) Normal or equivocal findings on ERP were obtained for 132 patients; 113 patients had F-RP on EUS. In contrast, F-RP was found in only 6 out of 45 CP cases on ERP (P < 0.0001). (2) We investigated the diagnostic capability of our new criteria for endoscopic retrograde cholangiopancreatography normal/equivocal pancreas compared to the traditional criteria. In cases where fewer than two points were defined as normal, the incidence of normal pancreas was significantly higher based on the new criteria than on the traditional criteria (P = 0.002). (3) No significant differences were found between the new criteria and the RC across all ERP grades.

Conclusion:

Our new proposed “normal-added EUS criteria” for diagnosing CP was equivalent to the RC.

Diagnostic Performance of Endoscopic Ultrasound (EUS) for Non-Calcific Chronic Pancreatitis (NCCP) Based on Histopathology

OBJECTIVES

Studies correlating endoscopic ultrasound (EUS) with histopathology for chronic pancreatitis (CP) are limited by small sample size, and/or inclusion of many patients without CP, limiting applicability to patients with painful CP. The aim of this study was to assess correlation of standard EUS features for CP with surgical histopathology in a large cohort of patients with non-calcific CP (NCCP).

METHODS

Adult patients undergoing total pancreatectomy and islet autotransplantation (TPIAT) for NCCP, between 2008 and 2013, with EUS <1 year before surgery. Histology from resected pancreas at the time of TPIAT (from head, body, and tail) was graded by a GI pathologist blinded to the EUS features. A fibrosis score (FS) ≥2 was abnormal, and FS≥6 was considered severe fibrosis. A multivariate regression analysis for the EUS features predicting fibrosis, after taking age, sex, smoking, and body mass index into consideration, was performed. A quantitative receiver operating characteristic (ROC) curve analysis was performed and Spearman rank correlation co-efficient (r) was calculated.

RESULTS

68 patients (56 females, mean±s.d. age-38.77±10.92) underwent TPIAT for NCCP with pre-operative EUS. ROC curve showed that four or more EUS features provided the best balance of sensitivity (61%), specificity (75%), and accuracy (63%). Although significant, correlation between standard EUS features and degree of fibrosis was poor (r=0.24, P<0.05). Multivariate regression analysis showed that main pancreatic duct irregularity was the only independent EUS feature (P=0.02) which predicted CP.

CONCLUSIONS

Correlation between standard EUS features and histopathology is poor in NCCP. MPD irregularity is an independent predictor for NCCP.

Plasma TGF-β1, MMP-1 and MMP-3 Levels in Chronic Pancreatitis

Chronic pancreatitis (CP) presenting clinically with upper abdominal pain, as well as exocrine and endocrine insufficiencies, is characterized by irreversible morphological and functional alterations in the pancreas. The objective of the present study is to investigate the plasma levels of transforming growth factor-β 1 (TGF-β1), matrix metalloproteinases MMP-1 (collagenase) and MMP-3 (stromelysin) in CP. A total of 71 CP patients and 100 control subjects were considered for the study. Plasma levels of TGF-β1, MMP-1 and MMP-3 were determined by enzyme-linked immunosorbent assay in patients and control subjects. The plasma levels of TGF-β1 and MMP-1 were significantly elevated in patients compared to control group (*P = 0.0301, **P < 0.0001). However, there was no significant difference in the plasma levels of MMP-3 between patients and controls (P = 0.3756). The elevated levels of TGF-β1 and MMP-1 may influence the inflammatory reactions by enhancing the pancreatic stellate cell activation and deposition of extracellular matrix resulting in pancreatic fibrosis. Thus, the present study highlights the role of fibrogenic cytokine marker TGF-β1 and matrix metalloproteinases in the pathogenesis of CP.