Pancreatic ultrasound

Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology.

Preparation

Fast the patient to reduce interference from overlying bowel gas, which may otherwise make visualization difficult.

Scanning technique

• 3-6 MHz curvilinear ultrasound transducer

• pancreatic body

  • anterior subxiphoid approach with the left lobe of the liver as an acoustic window

  • adjuncts to improve visualization

    • deep inspiration

    • push abdomen out to make a "beer belly" ¹

• pancreatic head

  • in addition to the above, a right subcostal approach with the transducer angled medially may be useful ¹

• pancreatic tail

  • can be difficult to visualize

  • a water filled stomach may be used as a window ¹

  • scan coronally in a right lateral decubitus position using the spleen as an acoustic window

Macroscopic appearances

• variable echogenicity

  • in young patients, the pancreas is generally less fatty and therefore usually hypoechoic

  • with age, fatty replacement of pancreas can result in echogenicity similar to surrounding mesenteric fat

  • fatty sparing of the uncinate process

Measurements

• AP diameter

  • head: 34 mm

  • body: 29 mm

  • tail: 32 mm

• length: 12-20 cm

• pancreatic duct: ≤3 mm

Pathologies

• acute pancreatitis: On the ultrasound, the affected pancreas usually appears swollen and hypoechoic, with surrounding tissue edema

• chronic pancreatitis: In a pancreatic ultrasound, findings may include an irregularly shaped gland, calcifications, and dilated pancreatic duct

• pancreatic pseudocyst: A well-defined, hypoechoic or anechoic fluid-filled sac adjacent to the pancreas

• pancreatic cysts: Can appear either anechoic or with internal debris on ultrasound imaging

• pancreatic adenocarcinoma: On ultrasound examination, it often presents as an irregular hypoechoic mass with poorly-defined margins and possible invasion of nearby structures

• pancreatic neuroendocrine tumors (PNETs): They may present on ultrasound as solid lesions with varying degrees of echogenicity

• pancreatic abscess and infection: On ultrasound, these may be seen as complex hypoechoic or hyperechoic fluid collections within the pancreas

• pancreatic trauma: Ultrasound may reveal focal areas of hypoechoic tissue, hematomas, or fluid collections as a result of damage to the gland

Practical Points

• pancreatic ultrasound is useful in distinguishing between inflammatory and neoplastic lesions but can have limitations in characterizing some complex cystic lesions

• the use of contrast-enhanced ultrasound can improve the detection of focal pancreatic lesions

• adjunct imaging modalities like computed tomography (CT) scan or magnetic resonance imaging (MRI) may be necessary for further evaluation in certain cases