Ultrasound Signs of Acute and Chronic Pancreatitis: Criteria, Wirsung's Duct, and Complications

Clinical Context

Correct interpretation of the ultrasound image requires clinical data. Acute pancreatitis is characterized by the acute onset of epigastric pain, fever, vomiting, elevated serum amylase and lipase, and predisposing factors: biliary stone, alcoholism, medication use (e.g., steroids), trauma (Diagnostic Ultrasound: Abdomen & Pelvis; ExpertDDx). Chronic pancreatitis is accompanied by prolonged symptoms and recurrent episodes of epigastric pain, typically radiating to the back.

Ultrasound Signs of Acute Pancreatitis

Main sonographic findings (ExpertDDx; Diagnostic Ultrasound: Abdomen & Pelvis):

Complications of Acute Pancreatitis

Extrapancreatic fluid collections occur within 4 weeks of the acute onset of pancreatitis and may resolve spontaneously. A pseudocyst forms when the fluid collection becomes a well-defined, walled-off collection of amylase. Additional sonographic findings may include ascites, thickening of the gallbladder wall, and thickening of the adjacent gastrointestinal tract (Textbook of Diagnostic Sonography).

Ultrasound Signs of Chronic Pancreatitis

Chronic pancreatitis develops due to recurrent episodes of acute pancreatitis with ongoing parenchymal destruction and persistent structural damage, which may lead to impairment of exocrine and endocrine function (Textbook of Diagnostic Sonography). The most common ultrasound signs (ExpertDDx; Diagnostic Ultrasound: Abdomen & Pelvis):

— Diffuse atrophy;
— Beading of the main pancreatic duct and dilation of side branches;
— Parenchymal and ductal calcifications.

Pathological examination reveals increased interlobular fibrous tissue and chronic inflammatory infiltration. Stones of calcium carbonate may be found within the ductal system, and pseudocysts are frequently encountered. Gland calcification is observed in 20%–40% of patients (Textbook of Diagnostic Sonography).

Sonographically, chronic pancreatitis has a mixed character. The involvement may be diffuse or localized. The echogenicity of the gland is usually increased beyond normal due to fibrous and fatty changes, with a mixture of hypoechoic (due to inflammation) and hyperechoic foci (Textbook of Diagnostic Sonography). Focal involvement with a mass-like appearance is possible, especially in the early stage of the disease; MRCP should look for a smoothly stenosed or normal main duct penetrating the altered zone (Diagnostic Ultrasound: Abdomen & Pelvis).

Wirsung's Duct

The differential key is the condition of the main pancreatic duct: in acute pancreatitis, ductal dilation is absent, whereas in chronic pancreatitis, beading dilation and side branch expansion are characteristic, as well as possible ductal calcifications. A dilated duct may communicate with a small pseudocyst (ExpertDDx).

Conclusion Formulation

The conclusion should reflect: the nature and extent of parenchymal changes (focal/diffuse, echogenicity), the condition of the gland contour, the presence of peripancreatic fluid collections or pseudocysts, the condition of the main pancreatic duct (dilation, beading, side branches), and the presence of calcifications. Distinguishing between acute and chronic processes relies on a combination of these signs with clinical data. [clarify] — specific template text for the conclusion is not provided in the sources.