Endoscopic ultrasound in chronic pancreatitis
- Michael B Wallace, MD, MPH
Michael B Wallace, MD, MPH
- Professor of Medicine
- Mayo Clinic, Jacksonville
- Massimo Raimondo, MD, FACG
Massimo Raimondo, MD, FACG
- Professor of Medicine
- Mayo Clinic, Jacksonville, FL
Endoscopic ultrasound (EUS) was developed initially for improving imaging of the pancreas [1-4]. The close proximity of the pancreas to the gastric and duodenal lumen permits EUS to obtain high-resolution imaging without interference by overlying bowel gas. (See "Endoscopic ultrasound: Normal pancreaticobiliary anatomy".)
The EUS diagnosis of chronic pancreatitis (CP) relies on quantitative and qualitative parenchymal and ductal criteria of which several have been published. It is generally accepted that, in the absence of any criteria, CP is unlikely, whereas in the presence of ≥5 criteria, CP is likely even though endoscopic retrograde cholangiography (ERCP) and standard tests of pancreatic function may still be normal. The clinical significance of fewer (one to four) features found on EUS is unclear, particularly when other diagnostic tests such as ERCP and function testing are normal.
EUS has allowed for the recognition of several features of CP that had not been appreciated with other imaging modalities. These include hyperechoic margins of the pancreatic duct, subtle lobularity of the parenchyma, small cystic changes in the parenchyma, and side branch duct ectasia (image 1A-B). The ability to detect these subtle changes has raised questions as to how chronic pancreatitis should be defined and whether EUS may be overly sensitive. However, accumulating evidence suggests that these early changes detected by EUS correlate with histologic changes of CP and may predict progression to more overt disease.
NORMAL PANCREATIC EUS
Several normal sonographic findings of the pancreas have been described, which allow for appreciation of the abnormalities that can be seen on EUS. The following findings were noted in a study involving 130,951 patients who underwent a screening examination with transabdominal ultrasonography (TUS) using a 3.5 or 5 mHz probe :
●Pancreatic duct diameter, which is measured similarly by TUS and EUS, was dilated (>3 mm) in only 0.49 percent of individuals and was more common in men and in older individuals. There was a strong trend toward increasing duct diameter with age.
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- NORMAL PANCREATIC EUS
- REFERENCE STANDARDS
- Functional testing
- Natural history
- Response to therapy
- INTEROBSERVER RELIABILITY
- LINEAR VERSUS RADIAL EUS
- THRESHOLD TO DIAGNOSE OR EXCLUDE CP BY EUS
- Rosemont classification
- SUPPLEMENTAL EUS TECHNIQUES
- DISCRIMINATION FROM PANCREATIC CANCER
- SUMMARY AND RECOMMENDATIONS