EUS-based Criteria For The Diagnosis Of Chronic Pancreatitis: The Rosemont Classification

Endoscopic ultrasound consists of a flexible endoscope which has a small ultrasound device built into the end. The ultrasound component produces sound waves that create visual images of the digestive tract which extend beyond the inner surface lining. EUS can be used to evaluate an abnormality below the surface such as a growth that was detected at a prior endoscopy or by X-ray. EUS can also be used to diagnose diseases of the pancreas, bile duct, and gallbladder when other tests are inconclusive, and can be used to determine the stage of cancers. Tissue samples, using a fine needle aspiration technique (FNA), can be obtained in real time with EUS guidance should an abnormality be seen. EUS is promising compared with other imaging modalities because it can potentially detect earlier forms of chronic pancreatitis.

Previous EUS-based classifications of chronic pancreatitis have used different EUS terminology, features, and criteria. Additionally, traditional radiographic criteria such as the Cambridge classification are dated. The authors' purpose was to establish consensus-based criteria for EUS features of chronic pancreatitis. An international consensus meeting was convened in Rosemont, Ill., in April 2007 attended by endosonographers from throughout North America and Japan who have expertise in evaluation and management of chronic pancreatitis. The conference was endorsed by the ASGE. Thirty-two internationally recognized endosonographers reviewed existing literature and discussed data before anonymously voting on terminology of EUS features, rank order, and category (major vs. minor criteria). Consensus was defined as greater than two thirds agreement among participants.

Major criteria for chronic pancreatitis were (1) hyperechoic foci with shadowing and main pancreatic duct (PD) calculi and (2) lobularity with honeycombing. Minor criteria for chronic pancreatitis were cysts, dilated ducts ≥3.5 mm, irregular pancreatic duct contour, dilated side branches ≥1 mm, hyperechoic duct wall, strands, nonshadowing hyperechoic foci, and lobularity with noncontiguous lobules. EUS findings were separated into major and minor criteria based on the stronger positive predictive value of major criteria which were thereby given more weight. The new Rosemont criteria, using a combination of major and/or minor criteria, categorizes the patient as having EUS features that are (1) consistent with chronic pancreatitis, (2) suggestive of chronic pancreatitis, (3) indeterminate of chronic pancreatitis, (4) normal.

The researchers concluded that the new Rosemont classification system represents an improvement over current means of EUS diagnosis for chronic pancreatitis. They acknowledge the results of their deliberations do not provide a validation of their recommendations, but intend to apply these criteria in a manner that provides easy and reproducible means of EUS diagnosis and grading of chronic pancreatitis so that they may be used to help guide patient care and future study design. In an accompanying editorial, Walter G. Park, MD, and ASGE President Jacques Van Dam, MD, PhD, FASGE, division of gastroenterology, Stanford University Medical Center, Cal., state that "despite being less than the perfect criterion standard, it remains the best to date."