Norm of Pancreas Ultrasonography (Pancreas Echogram, Pancreas Ultrasound)
The pancreas is properly located and positioned and is of normal size and shape, with a regular border, and a homogeneous pattern that is of finer texture than that of the peritoneum, more intense than area soft tissue, and less intense than the liver. Major supporting arteries and veins as well as the pancreatic duct are visible and normal.
Usage of Pancreas Ultrasonography (Pancreas Echogram, Pancreas Ultrasound)
Aids diagnosis of pancreatic inflammation, pseudocyst, or tumor; guidance for needle biopsy of pancreas; and ongoing monitoring of pancreatic carcinoma response to therapy (that is, change in the size of a tumor). Work-up of abdominal pain, particularly in clients with alcoholism, blunt abdominal trauma, gallbladder stones, and known hyperlipidemia because they are more prone to pancreatitis. The endoscopic/ intraductal method using mini probes with or without fine-needle aspiration is used experimentally to identify intraductal papillary-mucinous tumor and cystic lesions of the pancreas (see Endoscopic ultrasonography).
Description of Pancreas Ultrasonography (Pancreas Echogram, Pancreas Ultrasound)
Evaluation of pancreatic structure by the creation of an oscilloscopic picture from the echoes of high-frequency sound waves passing over the epigastric area (acoustic imaging). A variation of the technique involves moving the probe intraductally via endoscopic ultrasonography (see Endoscopic ultrasonography). The time required for the ultrasonic beam to be reflected back to the transducer from differing densities of tissue is converted by a computer to an electrical impulse displayed on an oscilloscopic screen to create a three-dimensional picture of the pancreas. An advantage of this test is that it can help diagnose acute pancreatitis retrospectively. In acute pancreatitis, the pancreas appears larger than normal and is less echogenic than the liver. The edema may cause compression of the inferior vena cava, and the pancreatic duct may appear enlarged. In chronic pancreatitis, calculi, shadows, strictures, or stenoses may be viewed in the pancreatic duct as well as calcified areas in the body of the pancreas. An abscess may appear as an irregular-shaped, highly echogenic structure with thick walls. Adenocarcinoma may cause the gland to appear enlarged, with an irregular border and absence of normal parenchymal echo pattern. True cysts may be differentiated from pseudocysts by their spherical, sonolucent appearance. Pseudocysts are nonspherical and may contain scattered echoes caused by debris contained within them.
Professional Considerations of Pancreas Ultrasonography (Pancreas Echogram, Pancreas Ultrasound)
Consent form NOT required.
- See Client and Family Teaching.
- This test should be performed before intestinal barium tests, or after the barium is cleared from the system.
- If the pancreas alone will be studied, a full stomach improves visualization of the posterior portion of the pancreas. The client should drink 500–1000 mL of tomato or orange juice or a cellulose suspension to distend the stomach. Alternatively, glucagon (1 mg) or a cellulose suspension may be administered intravenously, with 500 mL of water ingested a few minutes later to reduce stomach peristalsis. This causes the stomach to function as a fluid-filled window for scanning for up to 60 minutes.
- The client should wear a gown.
- Obtain ultrasonic gel or paste.
- The client is positioned supine in bed or on a procedure table.
- The area of the abdomen overlying the pancreas is covered with conductive gel, and a lubricated transducer is passed slowly and repeatedly over the pancreas. Scanning begins with transverse views taken at 1-cm intervals with the client in full inspiration. Scanning is started at the level of the xiphoid process and proceeds until the presence of intestinal gas hinders the view. The client may then be changed to a rising position, which moves gastric air to the fundus and distends the abdominal veins to provide landmarks for identifying the pancreas. This is followed by sagittal scanning, which alternates moving from midline to the right and then midline to the left, at 1-cm intervals. The client may be asked to suspend breathing on inhalation or exhalation to reduce motion artifact.
- Photographs of the oscilloscopic display are taken.
- Remove the gel from the skin.
- If a biopsy is performed, see Biopsy, Site-specific—Specimen.
Client and Family Teaching
- This transabdominal procedure is painless and carries no risks.
- If the biliary system will also be examined, a fast from food and fluids for 8 hours before the test is required.
- Oral ingestion of fluids before the procedure is for stomach distention that aids in the visualization of the pancreas.
- It is important to lie still during the procedure. You may be asked to stop breathing for a few seconds during the procedure.
- The procedure takes less than 60 minutes, and results are normally available within 48 hours.
Factors That Affect Results
- Dehydration interferes with adequate contrast between the organs and body fluids. Dehydration may cause the duodenum to be mistaken for the pancreas.
- Intestinal barium, gas, or food obscures the results by preventing proper transmission and deflection of the high-frequency sound waves.
- The more abdominal fat present, the greater is the attenuation (reduction in sound-wave amplitude and intensity), which interferes with the clarity of the picture. Abdominal muscles and cartilage may have the same effect, necessitating repositioning of the client.
- The stomach may interfere with views of the pancreatic anatomy in transverse scans.
- If the left lobe of the liver is very small (<2 cm), it will function poorly as an acoustic window.
- Severe dehydration, especially when combined with obesity, has the potential to impair visualization of the pancreas and the surrounding area.
- See also Endoscopic ultrasonography.